2015 design manual - shreveport, la

CITY OF SHREVEPORT

WATER AND WASTEWATER DESIGN STANDARDS

Date: September, 2015

In association with: IMS Engineers + Hall Builders delMet Services + WilliamsCreativeGroup

By:

In association with: IMS Engineers + Hall Builders delMet Services + WilliamsCreativeGroup

By:

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Table of Contents

Section 1 Introduction 1-1

1.1 Purpose of the Design Standards .................................................................................................... 1-1 1.2 Note to Design Engineer ..................................................................................................................... 1-1 1.3 Master Planning Documents ............................................................................................................. 1-2 1.4 Standard Specifications and Details ............................................................................................... 1-2 1.5 Design Standard References ............................................................................................................. 1-2

Section 2 Gravity Sewers 2-1

2.1 Wastewater Design Flow .................................................................................................................... 2-1 2.1.1 Design Flow .................................................................................................................................. 2-1 2.1.1.1 Per Capita Flows .......................................................................................................... 2-1 2.1.1.2 Peak Design Flow ........................................................................................................ 2-1 2.2 Gravity Sewer Design Calculations ................................................................................................. 2-2 2.3 Gravity Sewer Location ....................................................................................................................... 2-2 2.3.1 General ........................................................................................................................................... 2-2 2.3.2 Location in New Subdivisions .............................................................................................. 2-2 2.3.3 Location in Existing Streets ................................................................................................... 2-4 2.3.4 Public Lines in Commercial Developments .................................................................... 2-4 2.4 Gravity Sewer Pipe Separation Requirements .......................................................................... 2-4 2.4.1 Stormwater Drainage Ditch Crossings .............................................................................. 2-4 2.4.2 Protection of Water Supplies ................................................................................................ 2-4 2.4.3 Sanitary Sewers in Proximity with Storm Sewers ....................................................... 2-4 2.5 Gravity Sewer Pipe Size and Material ........................................................................................... 2-5 2.6 Gravity Sewer Cover ............................................................................................................................. 2-6 2.7 Minimum Slope and Pipe Velocities ............................................................................................... 2-7 2.8 Sewer Extensions ................................................................................................................................... 2-7 2.9 Sewer Service Connections ................................................................................................................ 2-7 2.10 Sewer Servitudes for Construction and Maintenance ......................................................... 2-8 2.11 Trenching and Bedding Requirements ...................................................................................... 2-9 2.11.1 Trenching ................................................................................................................................... 2-9 2.11.2 Bedding ....................................................................................................................................... 2-9

Section 3 Wastewater Manholes 3-1

3.1 Manhole Location .................................................................................................................................. 3-1 3.1.1 Manhole Spacing ........................................................................................................................ 3-1 3.2 Manhole Type .......................................................................................................................................... 3-2 3.2.1 Standard Manholes ................................................................................................................... 3-2 3.2.1.1 Pre-Cast Manholes ...................................................................................................... 3-2 3.2.1.2 Cast-In-Pace Manholes .............................................................................................. 3-2 3.2.2 Drop Manholes............................................................................................................................ 3-2 3.2.3 Vented Manholes ....................................................................................................................... 3-2 3.2.4 Discharge Manholes ................................................................................................................. 3-2 3.2.5 New Connections to Existing Manholes ........................................................................... 3-3 3.3 Manhole Diameter ................................................................................................................................. 3-3 3.4 Manhole Flow Channel ........................................................................................................................ 3-3

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3.5 Manhole Castings ................................................................................................................................... 3-3 3.6 Manhole Access....................................................................................................................................... 3-3 3.7 Manhole Coatings................................................................................................................................... 3-4 3.8 Manhole Height Requirements under Various Conditions including

Flood Plains ............................................................................................................................................. 3-4 3.8.1 Height of Manhole Sidewall ................................................................................................... 3-4 3.8.2 Traffic and Street Locations .................................................................................................. 3-4 3.8.3 Finished Landscape Locations ............................................................................................. 3-4 3.8.4 Non-Finished Landscape Locations ................................................................................... 3-4 3.8.5 Non-Traffic Areas ...................................................................................................................... 3-4 3.8.6 Flood Plains .................................................................................................................................. 3-4

Section 4 Wastewater Force Mains 4-1

4.1 Design Period .......................................................................................................................................... 4-1 4.2 Wastewater Design Flows .................................................................................................................. 4-1 4.3 Design Calculations ............................................................................................................................... 4-1 4.3.1 Wastewater Force Mains ........................................................................................................ 4-1 4.3.1.1 Hydraulic Design of Force Mains .......................................................................... 4-1 4.3.1.2 Hydraulic Transients ................................................................................................. 4-4

4.3.1.3 Required Analysis for Hydrogen Sulfide (H2S) Generation

and Release ........................................................................................................................... 4-6 4.4 Location……. ..................................................................................................................................... ….....4-7 4.5 Thrust Restraint Systems ................................................................................................................... 4-7 4.6 Force Main Servitudes Both Construction and Maintenance .............................................. 4-7

Section 5 Trenchless Technologies 5-1

5.1 General .............................................................................................................................................. 5-1 5.2 Boring and Jacking................................................................................................................................. 5-1 5.2.1 Boring ............................................................................................................................................. 5-1 5.2.2 Pipe Jacking .................................................................................................................................. 5-2 5.3 Horizontal Directional Drilling ......................................................................................................... 5-3 5.3.1 HDD for Gravity Sewers .......................................................................................................... 5-3 5.3.2 HDD for Force mains ................................................................................................................ 5-4 5.3.3 Engineering Calculations ........................................................................................................ 5-4 5.3.3.1 Pullback Calculations ................................................................................................. 5-5 5.3.3.2 Long Term Operation Calculations ...................................................................... 5-6 5.3.3.3 Geotechnical .................................................................................................................. 5-7 5.3.3.4 Land Requirements .................................................................................................... 5-7 5.4 Pipe Bursting ........................................................................................................................................... 5-7 5.4.1 General ........................................................................................................................................... 5-7 5.4.2 Pipe Bursting Design ................................................................................................................ 5-8 5.4.3 Crushed Liner Process ............................................................................................................. 5-9 5.5 Cured in Place Pipe ................................................................................................................................ 5-9 5.5.1 General ........................................................................................................................................... 5-9 5.5.2 CIPP Guidelines......................................................................................................................... 5-10 5.5.2.1 Lateral Repairs ........................................................................................................... 5-11

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Section 6 Wastewater Lift Station Design 6-1

6.1 Wastewater Design Flows .................................................................................................................. 6-1 6.2 Number of Lift Station Pumps .......................................................................................................... 6-1 6.3 Wetwell Design ....................................................................................................................................... 6-1 6.3.1 Wetwell Volume for Variable Speed Pumping .............................................................. 6-1 6.3.2 Wetwell Volume for Constant Speed Pumping ............................................................. 6-2 6.3.3 Wet Well Appurtenances ........................................................................................................ 6-2 6.4 Lift Station Design Calculations and Procedures ...................................................................... 6-2 6.4.1 Pumps Selection ......................................................................................................................... 6-3 6.4.1.1 Pumps .............................................................................................................................. 6-3 6.4.1.2 System Head Curve ..................................................................................................... 6-3 6.4.1.3 Pump Curves ................................................................................................................. 6-4 6.4.2 Force Main .................................................................................................................................... 6-4 6.5 Submersible Sewage Pump Station ................................................................................................ 6-4 6.5.1 Construction ................................................................................................................................ 6-5 6.5.2 Wet Well Coatings ..................................................................................................................... 6-5 6.5.3 Removal of Submersible Pump ............................................................................................ 6-5 6.5.4 Electrical Equipment ................................................................................................................ 6-5 6.5.5 Valve Vaults .................................................................................................................................. 6-6 6.6 Dry Pit Pump Station ............................................................................................................................ 6-6 6.7 Valves for Pump Stations .................................................................................................................... 6-6 6.8 Air Release Valves ................................................................................................................................. 6-7 6.9 Emergency Bypass Connection ........................................................................................................ 6-7 6.10 Flowmeter. ............................................................................................................................................. 6-7 6.11 Pressure Gauges .................................................................................................................................. 6-7 6.12 Hoisting and Lifting Equipment .................................................................................................... 6-7 6.13 Odor Control.......................................................................................................................................... 6-8 6.14 Pump Station Emergency Operations ......................................................................................... 6-8 6.14.1 General ........................................................................................................................................ 6-8 6.15 Lift Station Controls ........................................................................................................................... 6-8 6.15.1 HMI Signals and Alarms ....................................................................................................... 6-9 6.15.2 Telemetry System ................................................................................................................... 6-9 6.15.2.1 General .......................................................................................................................... 6-9 6.15.2.2 Hardware ................................................................................................................... 6-10 6.15.2.3 Diagnostics ................................................................................................................ 6-10 6.15.2.4 Requirements of Power ....................................................................................... 6-10 6.15.2.5 Communications ..................................................................................................... 6-10 6.15.2.6 Radio System ............................................................................................................ 6-10 6.15.2.7 RTU Outputs to SCADA ......................................................................................... 6-11 6.16 Lift Station Siting and Access ....................................................................................................... 6-12

Section 7 Water Distribution Mains 7-1

7.1 Potable Water Design Flows ............................................................................................................. 7-1 7.1.1 Annual Average Daily Flow ................................................................................................... 7-1 7.1.2 Peak Daily Flow .......................................................................................................................... 7-1 7.1.3 Peak Hourly Flow ...................................................................................................................... 7-1 7.1.4 Water Main Sizing ..................................................................................................................... 7-1 7.2 Fire Flow .............................................................................................................................................. 7-1 7.2.1 Peak Flow ...................................................................................................................................... 7-1

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7.3 Transmissions Mains and Distribution Mains ........................................................................... 7-1 7.4 Water System Pressure ....................................................................................................................... 7-2 7.5 Water System Design Calculations ................................................................................................. 7-2 7.6 Water Main and Extension Location .............................................................................................. 7-3 7.6.1 Residential (service) Water Line ......................................................................................... 7-3 7.6.2 Normal Water Main Location ............................................................................................... 7-3 7.7 Water Main Separation Requirements ......................................................................................... 7-3 7.7.1 Horizontal Separation from Sanitary Sewer Mains ..................................................... 7-3 7.7.2 Vertical Separation .................................................................................................................... 7-3 7.7.3 Separation from Storm Drains and Other Utilities ...................................................... 7-3 7.7.4 Separation from Sewer Manholes ....................................................................................... 7-4 7.8 Water Main Diameters ......................................................................................................................... 7-4 7.9 Water Main Looping and Deadends ............................................................................................... 7-4 7.10 Potable Water Valves ......................................................................................................................... 7-5 7.11 Water Main Cover ............................................................................................................................... 7-5 7.12 Surface Water Crossings for Water Mains ................................................................................ 7-5 7.12.1 Above Grade .............................................................................................................................. 7-5 7.12.2 Below Grade .............................................................................................................................. 7-5 7.13 Roadway Crossings for Water Mains .......................................................................................... 7-6 7.14 Air Release Valves and Blow offs for Water Mains ............................................................... 7-6 7.14.1 Air Valves .................................................................................................................................... 7-6 7.14.2 Blow offs ..................................................................................................................................... 7-6 7.15 Disinfection Requirements .............................................................................................................. 7-6 7.16 Existing Water Mains ......................................................................................................................... 7-6 7.17 Thrust Restraints ................................................................................................................................ 7-6 7.18 Water Main Servitudes for Construction and Maintenance .............................................. 7-6 7.18.1 Servitude ..................................................................................................................................... 7-7 7.19 Service Connections ........................................................................................................................... 7-7 7.19.1 Service Connection Materials and Sizes ........................................................................ 7-7 7.20 Fire Code .............................................................................................................................................. 7-7 7.21 Plumbing Code ..................................................................................................................................... 7-7

Section 8 Fire Hydrants 8-1

8.1 General Location and Design Requirements .............................................................................. 8-1 8.2 Residential Subdivision Hydrant Location Standards ............................................................ 8-2 8.3 Commercial and Multi-Family Hydrant Location Standards ............................................... 8-2 8.4 Private Fire Hydrants ........................................................................................................................... 8-2 8.5 Maximum Fire Hydrant Spacing ...................................................................................................... 8-3 8.6 Fire Hydrant Relocations .................................................................................................................... 8-3

Section 9 Line Valves, Air Relief Valves and Blow-off Chambers 9-1

9.1 Line Valves .............................................................................................................................................. 9-1 9.1.1 Isolation Valves .......................................................................................................................... 9-1 9.1.2 Pressure Reducing Valves ...................................................................................................... 9-2 9.2 Air Valves .............................................................................................................................................. 9-2 9.2.1 Requirements .............................................................................................................................. 9-2 9.2.2 Types ............................................................................................................................................... 9-2 9.2.3 Location and Sizing ................................................................................................................... 9-3 9.2 Blow-off Chambers ................................................................................................................................ 9-3

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9.3.1 Requirements .............................................................................................................................. 9-3 9.3.2 Locations ....................................................................................................................................... 9-3 9.3.3 Sizing ............................................................................................................................................... 9-3

Section 10 Water Meters 10-1

10.1 General Requirements .................................................................................................................... 10-1 10.2 Definitions ............................................................................................................................................ 10-1 10.2.1 Residential Meter .................................................................................................................. 10-1 10.2.2 Non-Residential Meter ........................................................................................................ 10-1 10.2.3 Irrigation Meter ..................................................................................................................... 10-1 10.2.4 Master Meter ........................................................................................................................... 10-1 10.2.5 Sub-Meter ................................................................................................................................. 10-1 10.2.6 Deduct Meter (Private Meter) ......................................................................................... 10-1 10.2.7 Temporary Meters (Fire Hydrant Meter) ................................................................... 10-1 10.2.8 Wholesale Meter (Customer City Meter) .................................................................... 10-2 10.3 Design Data .......................................................................................................................................... 10-2 10.3.1 Domestic Water Demand ................................................................................................... 10-2 10.3.1.1 Combined Fixture Value ...................................................................................... 10-2 10.3.1.2 Peak Domestic Demand ....................................................................................... 10-3 10.3.1.3 Pressure Adjustment ............................................................................................. 10-4 10.3.2 Irrigation Water Demand .................................................................................................. 10-4 10.3.3 Mechanical Demand ............................................................................................................. 10-4 10.3.4 Fire Demand ............................................................................................................................ 10-4 10.4 Meter Classification .......................................................................................................................... 10-5 10.4.1 Positive Displacement (PD) Meter ................................................................................. 10-5 10.4.2 Non-Displacement Meter ................................................................................................... 10-5 10.4.3 Compound Meter .................................................................................................................. 10-5 10.4.4 General Use Recommendations ...................................................................................... 10-5 10.5 Meter Service ...................................................................................................................................... 10-6 10.5.1 Domestic Service Meters.................................................................................................... 10-6 10.5.2 Large Domestic Service Meters ....................................................................................... 10-6 10.5.3 Fire Service Detector Check Device ............................................................................... 10-6 10.5.4 Irrigation Service Meter ..................................................................................................... 10-6 10.5.5 Combined Water and Fire Services Meters ................................................................ 10-6 10.5.5.1 Small Combined Water and Fire Service Meter(s) ................................... 10-6 10.5.5.2 Large Combined Water and Fire Service Meter(s) ................................... 10-6 10.6 Location and Installation ............................................................................................................... 10-6 10.6.1 Accessibility............................................................................................................................. 10-6 10.6.2 Minimum Length of Unobstructed Pipe ...................................................................... 10-7 10.6.3 Miscellaneous Items ............................................................................................................ 10-7 10.7 Meter Box and Vault ......................................................................................................................... 10-7 10.7.1 General ...................................................................................................................................... 10-7 10.7.2 Meter Box ................................................................................................................................. 10-8 10.7.3 Meter Vault .............................................................................................................................. 10-8 10.8 Special Design Considerations ..................................................................................................... 10-8 10.8.1 Deduct Meter .......................................................................................................................... 10-8 10.8.1.1 General ........................................................................................................................ 10-8 10.8.1.2 Typical Configurations ......................................................................................... 10-8 10.8.2 Wholesale Meter.................................................................................................................... 10-8 10.8.2.1 General ........................................................................................................................ 10-8

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vi

10.8.2.2 Typical Configurations ......................................................................................... 10-8

Section 11 Cross Connection Protection 11-1

11.1 Special Design Considerations ..................................................................................................... 11-1 11.2 Backflow Prevention Devices ....................................................................................................... 11-1 11.3 Backflow Prevention for Commercial, Industrial, and Multi Family Residences ................................................................................................................ 11-1 11.4 Backflow Prevention for Irrigation System ............................................................................ 11-2 11.5 Locations for Backflow Prevention Devices ........................................................................... 11-2 11.5.1 Locations .................................................................................................................................. 11-2 11.5.1.1 Fire Sprinkler Systems ......................................................................................... 11-2 11.5.1.2 Irrigation / Lawn Sprinkler Systems .............................................................. 11-2 11.5.1.3 Auxiliary Sources .................................................................................................... 11-2 11.5.1.4 Wastewater Treatment Plants, Pump Stations and Water Reduction Facilities ................................................................................................... 11-2 11.5.1.5 Water Treatment Plants ...................................................................................... 11-3 11.5.1.6 Plating and Chemical Companies ..................................................................... 11-3 11.5.1.7 Other Locations ....................................................................................................... 11-3 11.6 Plumbing Code ................................................................................................................................... 11-3

Section 12 Pipe Aerial Crossings 12-1

12.1 General Considerations .................................................................................................................. 12-1 12.2 Design Considerations .................................................................................................................... 12-1

Section 13 Pipe Stream Crossings 13-1

13.1 Design Considerations .................................................................................................................... 13-1 13.2 Material and Appurtenances ........................................................................................................ 13-2 13.3 Erosion Control .................................................................................................................................. 13-2

List of Figures Figure 2-1 Sewer Line Location – Guidance Schematic ................................................................................... 2-3 Figure 5-1 Horizontal Directional Drilling Pullback ......................................................................................... 5-6 Figure 7-1 Cul-De-Sac Dead Ends ............................................................................................................................. 7-4 Figure 10-1 Water Flow Demand per Fixture Value – Low Range ........................................................... 10-3 Figure 10-2 Water Flow Demand per Fixture Value – High Range ........................................................... 10-3

List of Tables Table 1 1 Minimum Design Life ................................................................................................................................. 1-1 Table 2-1 Gravity Sewer Cover .................................................................................................................................. 2-6 Table 2-2 Minimum and Maximum Slopes for Gravity Sanitary Sewer .................................................... 2-7 Table 2-3 Minimum Sewer Servitude Widths ...................................................................................................... 2-8 Table 3-1 Diameter of Manholes ............................................................................................................................... 3-3 Table 5-1 Casing Sizes .............................................................................................................................................. 5-2 Table 5-2 Pipe Bursting Design ................................................................................................................................. 5-8 Table 5-3 CIPP Method Limitations ....................................................................................................................... 5-10 Table 6-1 Lift Station Size Classification ................................................................................................................ 6-8

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vii

Table 6-2 Lift Station Control Elements ................................................................................................................. 6-9 Table 6-3 Lift Station HMI Signals and Alarms ................................................................................................... 6-9 Table 6-4 Lift Station RTU Outputs ........................................................................................................................ 6-11 Table 8-1 Fire Hydrant Spacing ................................................................................................................................. 8-3 Table 9-1 Line Valve Spacing ...................................................................................................................................... 9-1 Table 10-1 Recommended Fixture Value ............................................................................................................ 10-2 Table 10-2 Pressure Adjustment Factors ............................................................................................................ 10-4 Table 10-3 Recommended Use of Various Water Meters General Category ........................................ 10-5 Table 10-4 Required Minimum Straight Unobstructed Pipe Length for Water Meter ..................... 10-7

Appendices Appendix A – Consultant Rating Form

Appendix B – Plan Review Checklist

Appendix C – References

Appendix D – Design Phases

1-1

Section 1

Introduction

1.1 Purpose of the Design Standards The purpose of this manual is to provide guidelines and minimum design criteria for the design of

water and wastewater systems for the City of Shreveport (the City) as part of:

Consent Decree Program Projects

Capital Improvement or Bond Projects

Private Development Projects

In the case of Private Development Projects it is assumed that the infrastructure constructed will be

transferred and donated to the City for operation and maintenance. The manual also applies to

existing systems being expanded, modified, upgraded and rehabilitated, as well as construction of new

facilities. These standards are based on commonly practiced engineering principles, pertinent

textbooks and literature. While these standards establish the minimum design requirements, it is not

intended to substitute for any professional engineering judgment by the Design Engineer who will

assume ultimate responsibility for selection, reference and appropriate application of this manual.

Any exceptions to these standards or variation from these standards shall be submitted in writing

with detailed justification, and calculations to the City’s Engineering and Environmental Services

(EES) Department, and where applicable the Louisiana Department of Health and Hospitals. All units

of measurement used in this manual are United States standard units unless otherwise noted.

1.2 Note to Design Engineer The Design Engineer shall familiarize themselves with the contents of this manual, including the

appendices. These appendices include the City’s Consultant Rating Form (Appendix A), an updated

plan review checklist (Appendix B), additional references (Appendix C), and an overview of design

phases (Appendix D). The Design Engineer shall update their Master/Guide specifications and/or

pertient City specifications to suit the needs of each individual project. The Design Engineer shall

abide by these requirements in completing design.

Minimum design life required by the City, for different types of installations are stated below in Table

1-1.

Table 1-1 Minimum Design Life

Type of Installation Minimum Design Life (years)

Pipes 50 years

Mechanical Equipment 20 years

Electrical Equipment* 20 years

Variable Frequency Drives 15 years

Structural Installations 50 years

*- Excluding Variable Frequency Drives.

Section 1 Introduction

1-2

1.3 Master Planning Documents The City’s Wastewater System Master Plan will include a computerized hydraulic model (Infoworks CS

by Innovyze). This model will be able to provide design flows for each of the City’s Sanitary Sewer

Service Area for both Wet weather and Dry Weather conditions. These flows will be the basis for

sewer design as described below in Section 2.1, Wastewater Design Flows. In the areas where the

flows are not included in the model, the sewer design shall be based on population estimates as

described in Section 2.1.

The Shreveport-Caddo Master Plan 2030 provides additional information on proposed land use and

future facilities to serve the City of Shreveport. An additional planning document that should be

consulted is the Caddo Parish Water Master Plan dated 2012. This document examines the potential

expansion of both Water and sewer into areas of Caddo Parish adjacent to the City of Shreveport.

1.4 Standard Specifications and Details The City of Shreveport has a set of standard specifications and details for Water and Wastewater

Projects. These specifications provide the level of expectation of quality for the construction of water

and wastewater projects. However, the standard specifications and details may not apply to all

projects, and therefore the Design Engineer is advised to review these standard documents, and

update their specifications and/or details as it applies to the project. The Design Engineer can request

the latest version of these documents from the City’s EES Department.

1.5 Design Standard References The Design Engineer shall prepare design documents that conform to the Consent Decree Program (if

applicable) and the adopted version of all applicable local, state, and federal regulations. The Design

Engineer shall verify the applicable codes and standards and their editions shall be verified at the time

of design. These Standards and references include but are not limited to:

ACI 318, Building Code Requirements for Structural Concrete

ACI 530, Building Code Requirements for Concrete Masonry Structures

Air Moving and Conditioning Association (AMCA)

AISC 341Seismic Provisions for Structural Steel Buildings, Including Supplement No. 1

AISC Manual of Steel Construction

AISC Specifications for Structural Joints Using ASTM A 325 or A 490 Bolts

AISI Specifications for the Design of Light-gauge, Cold-formed Steel Structural Members

Aluminum Association Specifications for Aluminum Structures

American Concrete Institute (ACI) 350, Code Requirements for Environmental Engineering

Concrete Structures

American Institute for Steel Construction (AISC), Steel Construction Manual

American National Standards Institute (ANSI) /Hydraulic Institute Standards


1-3

American Society for Testing and Materials (ASTM)

American Society of Civil Engineers (ASCE) and Water Pollution Control Federation, ASCE

Manual and Report on Engineering Practice No. 60 - Gravity Sanitary Sewer Design and

Construction

American Society of Heating Refrigerating and Air Conditioning Engineers (ASHRAE)

American Society of Mechanical Engineers (ASME)

American Water Works Association (AWWA) Standards

American Welding Society Structural Welding Code AWS D1.1

Americans with Disabilities Act (ADA)

ANSI/AWWA D110, Wire- and Strand-Wound, Circular, Pre-stressed Concrete Water Tanks

ASCE 7, Minimum Design Loads for Buildings and Other Structures

ASCE and Water Pollution Control Federation, ASCE Manual and Report on Engineering Practice

No. 76 – Design of Municipal Wastewater Treatment Plants

Associated Air Balance Council (AABC)

Brick Industry Association

City of Shreveport, Standard Specifications for Public Works Construction

City of Shreveport, Standard Details

City of Shreveport, Stormwater Guidelines

City of Shreveport, Unified Development Code

Code of Ordinances, City of Shreveport, Louisiana

Design of Wastewater and Storm water Pumping Stations, Manual of Practice FD-4, Water

Environment Federation (WEF)

ICC/ANSI 117.1 - Useable Buildings and Facilities

IEEE 519 Recommended Practices for Harmonic Control in Electrical Power Systems

IEEE Standard 142 for Recommended Practices for Grounding

Institute of Electrical and Electronics Engineers (IEEE)

International Building Code (IBC)

International Energy Conservation Code

International Fire Code (IFC)


1-4

International Fuel Gas Code (IFGC)

International Mechanical Code (IMC)

International Society of Automation (ISA)

Louisiana Department of Environmental Quality (LADEQ)

Louisiana Department of Health and Hospitals, Office of Public Health (OPH)

Louisiana Office of State Fire Marshal’s codes

Louisiana Standards For Waterworks and Construction

Louisiana State Plumbing Code

National Association of Architectural Metal Manufacturers: Metal Bar Grating Manual and

Heavy Duty Metal Bar Grating Manual

National Electrical Manufacturers Association (NEMA)

NFPA 1 Fire Code

NFPA 101 Life Safety Code

NFPA 70, National Electrical Code

NFPA 820 Standard for Fire Protection in Wastewater Treatment and Collection Facilities

Occupational Safety and Health Act (OSHA)

Pumping Station Design, Latest Edition by Robert L. Sanks

Railroad Standards and Permit Conditions

Sheet Metal and Air Conditioning Contractors National Association (SMACNA)

State of Louisiana Department of Transportation (DOT), Standard Specifications for Roads and

Bridges (latest edition)

Steel Joist Institute Standard Specifications

Ten States Standards, Recommended Standards for Wastewater Facilities, Great Lakes - Upper

Mississippi River Board of State and Provincial Public Health and Environmental Engineers

Uni-Bell Plastic Pipe Association, Handbook of PVC Pipe, Design and Construction

United States Environmental Protection Agency (EPA)

WEF, MOP No. 8, Design of Wastewater Treatment Facilities

Additional references can be found in Appendix C.

2-1

Section 2

Gravity Sewers

The following design standards are provided as guidelines only. The Design Engineer is responsible

for the design of gravity sewers (includes submains, trunk mains and interceptors), and evaluating all

requirements on a case by case basis. See Section 1.1 regarding exceptions.

2.1 Wastewater Design Flow All sanitary sewers shall be designed to carry the estimated wet weather design peak flow from the

area that ultimately contributes to the sanitary sewer. The City will provide design flow information,

if available, to the Design Engineer based on the hydraulic model. It shall be the Design Engineer’s

responsibility to review this data, and based on detailed survey information and field review of the

project collection system, note any potential inconsistencies in the provided flow data and present

them to the City. The Design Engineer is responsible for submitting written requests to the City for

confirmation of the selected alternative and recommendations based on the hydraulic model. In the

areas where the flows are not included in the hydraulic model, the sewer design shall be based on

population estimates as described below.

2.1.1 Design Flow 2.1.1.1 Per Capita Flows

New sewer system shall be designed on the basis of population estimates for the project area and the

average daily per capita flow. The estimated population shall be multiplied by the estimated per capita

wastewater contribution to obtain the average daily flow estimations. The average per capita

wastewater flow plus groundwater infiltration in Louisiana is 150 gpcd (Guidance for Evaluating

Infiltration and Inflow for State Revolving Fund Projects). Different figures for per capita wastewater

flow may be used if supported by flow measurement and census data.

Commercial, industrial and institutional flows may vary significantly depending on the industry type,

size, and operational techniques, among other factors. Such flows shall be estimated based on historic

water usage records, flow measurements or design standards acceptable to the City. These flows shall

be included as necessary for estimating the per capita flow from the project.

2.1.1.2 Peak Design Flow

When designing sanitary sewers, the average daily flow shall be peaked using the ratio of peak hourly

flow to design average flow. If field data, data from models or studies is not readily available, the Peak

Flow factor (PF) can be obtained using the following relationship:

( )

(

)

Where P = the population in thousands

Peak Design Flow (PDF) shall be obtained by multiplying the sum of average daily

flows generated from residential and commercial areas by their respective PF.

Section 2 Gravity Sewers

2-2

( )

( )

Peak flow includes both peak daily flow and rainfall-dependent infiltration/inflow and

groundwater infiltration.

2.2 Gravity Sewer Design Calculations The Designer shall use Manning’s Equation for hydraulic design, and sizing of gravity sewers. A

roughness coefficient “n” value of 0.013 should be used. This value compensates for offset joints, poor

alignment, grade settlement, sediment deposition, and the effect of slime and grease build-up in

sanitary sewers.

Manning’s Equation:

(

)

Where:

Q is the discharge (cubic feet per second, cfs)

A is the cross sectional area of flow (square feet, ft²);

n is the roughness coefficient, assume n to be 0.013 for all pipe materials;

R is the hydraulic radius, which is the area of flow over the wetted perimeter (ft.);

S is the slope (feet/feet).

And:

(

)

Where:

V is the velocity, feet per second.

2.3 Gravity Sewer Location 2.3.1 General All sanitary sewers shall be placed in public street rights-of-ways or within servitudes.

2.3.2 Location in New Subdivisions Public sewer lines shall be located in public right-of-ways or in a dedicated servitude that is at least

20 feet wide. See Table 2-3 in this section for more details. Any exceptions to this shall be submitted to

the City for approval.


2-3

Prior to paving of streets or sidewalks, sewer mains and services shall be in place, or the developer

shall provide necessary casing for such utilities. Backlot or sidelot servitudes will not be allowed. See

Figure 2-1 (below) for a guidance schematic.

Figure 2-1 Sewer Line Location – Guidance Schematic

Notes:

1) This drawing is normally for streets oriented East-West. Flip drawing 90 degrees counter-clockwise for streets oriented North-South.

2) Water and sewer lines shall be located in public Right-Of-Ways. 3) Minimize servitude overlap on private property lines. 4) Dedicated servitudes on private property allowed only if there are limitations in using the

public Right-Of-Way. Design Engineer shall submit written justification for City review. 5) Gravity sewer shall be located normally on South (for East-West streets) or on the East (for

North-South streets) from the centerline of the paved street. 6) Do not locate sewer/water service lines beneath private walkways or driveways. 7) Maintain five (5’) feet separation (minimum) from existing/proposed utilities, poles, and

other structures. 8) Locate gravity sewers and water mains at the center of the servitude. 9) Water mains shall be located on the opposide side of the street from gravity sewers.


2-4

2.3.3 Location in Existing Streets When sanitary sewers are to be installed in an existing street, factors such as curbs, gutters, sidewalks,

traffic conditions, traffic lane condition, pavement conditions, future street improvement plans, and

existing utilities shall be considered. As outlined in the City’s Ordinance (78-102), no existing

pavement shall be cut without the approval of the City Engineer. When sanitary sewers are extended

for developments, they shall be extended to the furthest property line to facilitate future expansion.

2.3.4 Public Lines in Commercial Developments The Design Engineer shall locate all sewers within City right-of-ways.

2.4 Gravity Sewer Pipe Separation Requirements 2.4.1 Stormwater Drainage Ditch Crossings Whenever applicable, sanitary sewers crossing over drainage ditch(es) shall be pressure tested from

manhole to manhole to confirm 100 percent water tightness. Minimum pipeline cover under drainage

ditches shall be five (5) feet. In instances where the specified cover is not achievable, a concrete

encasement shall be used. The Design Engineer shall also meet the requirements stated in Section 13

of this manual.

2.4.2 Protection of Water Supplies There shall be no physical connections between a public or private water supply system and a sanitary

sewer or its appurtenances, that would permit the passage of any wastewater into the potable water

supply. The Design Engineer shall design sanitary sewers to be installed at least 10 feet horizontally,

measured edge-to-edge, from any existing or proposed water line. In cases where it is not practical to

maintain a 10-foot separation, the City may allow deviation (upon review) on a case-by-case basis if

supported by data from the Design Engineer. Such deviations may allow installation of the sewer

closer to a water main, provided that the following conditions exist:

Water main is in a separate trench or on an undisturbed earth shelf located to one side of the

sewer

Water main is at an elevation such that the bottom of the main is at least 18 inches above the

top of the sewer

Sanitary sewers crossing water mains shall be designed to provide a minimum vertical separation

distance of 18 inches between the outside of the water main and the outside of the sewer. This shall be

the case where the water main is either above or below the sewer. The crossing shall be designed so

that the sewer joints will be equidistant and as far as possible from the water main joints. All water

mains crossing sanitary sewers shall be encased in concrete. Normally, water mains shall be located

above sanitary sewers. When it is impossible to obtain proper horizontal and vertical separation as

stipulated above, both the water main and the sewer shall be restrained with slip-on joint or

mechanical joint pipe complying with the public water supply design standards, and shall be pressure

tested to 150 psi to verify water tightness before backfilling.

2.4.3 Sanitary Sewers in Proximity with Storm Sewers The Design Engineer shall provide a minimum horizontal separation greater than or equal to 3 feet

(outside-to-outside) for new parallel sewer construction near storm sewers.


2-5

The Design Engineer shall provide a minimum vertical separation greater than or equal to 12 inches

for new sewer crossings over storm sewers. When horizontal separation is less than 3 feet, the

minimum sanitary sewer pipe material specification shall be AWWA C900 or AWWA C905 (DR 18)

PVC pipe or pressure class 150 Ductile Iron Pipe (DIP)with Protecto 401 coating from manhole to

manhole. When vertical separation is less than one foot, a neoprene pad shall be placed between the

two pipes. Any exceptions to this standard shall be submitted for City approval.

Storm sewers shall not be connected to sanitary sewers. Storm sewers that are known or are found to

be connected to sanitary sewers, during construction activities, field activities, or surveying, shall be

disconnected and capped.

2.5 Gravity Sewer Pipe Size and Material All sewers shall be designed to prevent damage from superimposed live and dead loads. Proper

allowance for loads on the sewer shall be made for soil and potential groundwater conditions, as well

as the width and depth of the trench. Refer to ASTM D2321 or C12 when appropriate. Owing to ease of

maintenance, minimum size for gravity sewers is set at 8 inches diameter. Gravity sewers above 48

inches in diameter are considered special design; the design engineer shall consider relevant

geotechnical information, trench type, and soil corrosivity in completing design for gravity sewers

above 48 inches in diameter. Furnish in the Design Criteria report to the City, relevant design

calculations, and justifications for gravity sewers of size 48 inches and above.

Pipe material shall not change from manhole to manhole. In addition, gravity sewer pipe material shall

conform to the City’s Standrad Specification Section 209.

Polyvinyl Chloride Pipe (PVC) is preferred for gravity sewers up to 48 inches in diameter.

Sizes 8 inches to 15 inches shall be PVC (ASTM D3034, DR 35 minimum) solid wall pipe. Sizes

18 inches and above shall be PVC (ASTM F679, PS 46 minimum) solid wall pipe.

Certa-Flo gravity sewer piping may be considered for restrained PVC pipe applications up to

12 inches in diameter.

Where pipe depth is greater than 20 feet, DR 26 (minimum) solid wall pipe shall be provided.

Closed Profile Wall PVC Piping is preferred for gravity sewers over 48 inches in diameter.

However, the Design Engineer shall perform all relevant calculations (as stated above) to

justify the use of closed profile wall PVC piping.

Closed profile wall PVC piping shall meet the requirements of ASTM F1803, and shall be rated

for a minimum pipe stiffness of 46 psi.

Ductile Iron Pipe (DIP) is permitted only in instances where it is not practical to use PVC or closed

profile wall PVC piping or it is mandated by an utility owner (ex: petrochemical pipe crossings).

Design Engineer shall submit a detailed written justification for selecting DIP over PVC and closed

profile wall PVC piping.


2-6

Ductile iron pipes, when used, shall be of the pressure class listed below.

Pipe Sizes (inches) Min. Pressure Class (psi)

8-12 350

14-20 250

24 200

30-64 150

Smaller DIP shall be considered for shallow bury, road crossings, and creek crossings

(encasement may be required). The Design Engineer shall use the recommendations for

encasement found in Section 7 and Section 13 as applicable.

See construction requirements for encasement in the applicable sections of the City’s Standard

Specification Sections for Roadways, Excavation and Backfill, and applicable Standard Plans.

Where special conditions warrant, additional details may be shown on the project plans, or

the Special Provisions may include such special requirements.

High Density Polyethylene Pipe (HDPE) and fusible PVC

HDPE and fusible PVC pipe shall only be used for trenchless design and construction. HDPE

piping shall be per the City’s Standard Specifications with heat fusion welded joints. Any

exceptions to this shall be submitted in writing for the City’s review and approval.

For piping above 64 inches in diameter, the Design Engineer shall consult the City Engineer

regarding their preference for pipe materials. Deflection at joints shall be limited to 50% of

the manufacturer’s recommendations.

2.6 Gravity Sewer Cover Table 2-1 lists the minimum cover requirements for gravity sewers. An unimproved area occurs when

there is just natural ground with no permanent pavement or curb and gutter. An improved area

occurs where there is permanent paving with base, curb and gutter and other ground construction.

The depth of cover is determined from the top of pipe to the finished ground surface. The Design

Engineer must consider the depth requirement to service adjacent properties to the sewer. The

Design Engineer shall also consider possible buoyancy of the sewers due to high groundwater

conditions and prevent possible flotation of the pipe.

In cases where the Design Engineer is unable to maintain minimum cover, these locations shall be

designed to handle the possible loads that the sewer may be subjected to. Also, the Design Engineer

shall contact the owner of the Highway or Railroad for additional requirements.

Table 2-1 Gravity Sewer Cover

Size of Sewer Minimum Depth In Feet

Unimproved1 Improved Highway/Railroad

≤18 inches 6 5 6

>20 inches 7 6 6

1 – Design Engineer to consider future improvements and grades in consultation with the City Engineer when designing gravity sewers in unimproved

areas.


2-7

2.7 Minimum Slope and Pipe Velocities The Design Engineer shall design all sanitary collector and trunk sewers to provide a minimum

velocity of 2 feet per second (fps) when flowing full (for pipes 42-inches in diameter and less), or a

minimum velocity of 3 fps when flowing full (for pipes greater than 42-inches in diameter), and a

maximum velocity of 10 fps when flowing full, as calculated using Manning’s equation.

Table 2-2 presents the minimum and maximum slopes that shall be used as design criteria. Velocity

shall be calculated at the design flow.

Table 2-2 Minimum and Maximum Slopes for Gravity Sanitary Sewer

Sewer Pipe Diameter

Inches

Minimum Slope

%

Maximum Slope

%

8 0.4 8.34

10 0.28 6.20

12 0.22 4.86

14 0.17 4.0

15 0.15 3.61

16 0.14 3.31

18 0.12 2.83

21 0.10 2.30

24 0.08 1.93

27 0.067 1.65

30 0.058 1.43

36 0.046 1.12

42 0.037 0.91

If the Design Engineer prefers to use minimum slopes less than those indicated, it shall be submitted

to the City in writing with justification. Such cases may be approved by the City on a case-by-case

basis.

Similarly, velocities greater than 10 fps will be considered on a case-by-case basis, with proper

consideration to pipe material, abrasive characteristics of the wastewater, turbulence, thrust at

changes of direction, and protection against pipe and bedding displacement.

2.8 Sewer Extensions The Design Engineer shall calculate or obtain from the City (if available) the design flow rates for

sewer extensions. The service areas for sewer extensions shall be clearly identified and coordinated

with the Wastewater Master Plan to see if additional areas for the sewer extension will be required.

2.9 Sewer Service Connections The Design Engineer shall design laterals to be replaced up to the property line or permanent

servitude line with minimum 4-inch PVC (SDR 35) service laterals, and a minimum slope of one

percent.


2-8

A new PVC cleanout on or within the property line, with a tee/wye shall be provided per Louisiana

State Plumbing Codes. Service laterals connected to DIP shall use ductile iron wyes with Protecto 401

Ceramic Epoxy lining.

All existing sewer service locations shall be replaced, and new service connections shall be designed to

service both present and future connection requirements. The Design Engineer shall review the

requirements for service connections as stated in the City Standard Specification 2000 and Standard

Plan 2200-10.

2.10 Sewer Servitudes for Construction and Maintenance The Design Engineer shall place all new or rehabilitated sewers within existing City right-of-ways or

servitudes. If it is determined (and approved by the City) that the project will be performed outside of

existing right-of-way or existing servitudes, then it will be necessary to obtain a new servitude.

The Design Engineer shall request a surveyor to prepare a legal description for the required servitude.

This request shall include, but not be limited to, the following information:

Type of Servitude: Permanent or temporary/construction

Purpose of Servitude: Water and/or wastewater servitude

Project Schedule: Planned advertisement and construction date

Location Map: A map showing location of servitude with coordinates and dimensions.

Verification that a minimum of 25 feet of vertical clearance above the servitude is available to

permit the operation of backhoes and trackhoes. Any exception to this shall be approved by the

City.

When placed in servitudes owned by other entities (ex: Department of Transportation and

Development or Kansas City Souther Rail Road), design shall be in conformance with the

entity’s requirements.

Table 2-3 (below) lists the recommended minimum width requirements for sewer servitudes.

Table 2-3 Minimum Sewer Servitude Widths

Size of Sewer

Inches

Depth of Sewer

Feet

Servitude Width

Feet

8-12 ≤ 8

>8

20

25

15-24 ≤ 8

>8

25

35

30-66 ≤ 8

>8

40

50

72 and larger ≤ 8

>8

60

70


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2.11 Trenching and Bedding Requirements See Construction requirements for trench excavation, bedding and backfill in the applicable sections of

the Specification Section 1002 Excavation and Backfill and as shown in Standard Plan 2000-1. Where

special conditions warrant, additional details may be shown on the project plans.

2.11.1 Trenching The width of the trench shall be ample to allow the pipe to be laid and jointed properly and to allow

the bedding and haunching to be placed and compacted to adequately support the pipe. The trench

sides shall be kept as nearly vertical as possible. When wider trenches are specified, appropriate

bedding class and pipe strength shall be used.

2.11.2 Bedding Bedding shall be designed in accordance with:

Rigid Pipe: Bedding equal to Classes A, B, or C, or crushed stone as described in ASTM C12

Flexible Pipe: Material equal to Classes I, II, or III, as described in ASTM D2321


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3-1

Section 3

Wastewater Manholes

3.1 Manhole Location Manholes shall be installed at the following locations:

Changes of grade or slope.

Changes of pipe size.

Changes of horizontal or vertical alignment.

Changes in pipe material.

Pipe intersections except with service connections less than 6-inches in diameter.

Change in flow direction.

The end of each public sewer line.

The terminus of dead-end sewers.

Discharge of private pump station force main.

Manholes shall not be placed in any of the following locations:

Inaccessible areas.

In the flow line of an existing creek or drainage area.

In sidewalks, crosswalks, or pedestrian ramps.

In driveways.

In gutters or curb lines.

In freeway ramps or lanes.

Between railroad tracks (manholes within a railroad right-of-way shall be located a minimum of

15 feet from track bed and in accordance with the requirements of the railroad.

Within 15 feet of any structure, including subterranean or overhead structures.

Furthermore, when locating manholes in the street or paving, the Engineer shall locate them such that

they are outside of the wheel-path as much as possible.

3.1.1 Manhole Spacing Manhole spacing shall be a maximum center to center distance of 400 feet for collection system piping

up to 15-inches in diameter. For sewers 18-inches to 30-inches, the maximum center to center

Section 3 Wastewater Manholes

3-2

distance shall be 500 feet. Requirements of the Ten State Standards (TSS) shall apply for other sewer

sizes.

3.2 Manhole Type The following are the types of manholes installed in the City’s wastewater collection system.

3.2.1 Standard Manholes These manholes are placed at standard locations for manholes. Design all new manholes as pre-cast

manholes or cast-in-place manholes. Design all manholes with sufficient inside dimensions to perform

inspection and cleaning operations. During the preliminary design phase, the Design Engineer shall

determine the appropriate size and orientation of each manhole.

The minimum manhole diameter is 48-inches. Manholes greater than 72-inches in diameter shall be

considered special design, and approved by the City.

3.2.1.1 Pre-Cast Manholes

The Design Engineer shall review Standard Plan 2200-1 and Standard Specification Sections 209 and

2200 for requirements such as depth of pipe, type of pipe material, wall thickness and other design

factors. For any variation in design from these documents, it shall be necessary to show detail(s)

including the invert on the construction drawings and to provide structural calculations, as needed,

for approval by the City.

3.2.1.2 Cast-In-Pace Manholes

The Design Engineer shall review and use Standard Plan 2200-2 unless found unsuitable for the

project, in which case it shall be necessary to show the detail on the construction drawings and to

provide structural calculations, as needed, for approval by the City.

3.2.2 Drop Manholes These manholes are used where the incoming pipe or pipes are 2 feet or higher than the manhole

invert. Drop manholes should be constructed with an outside drop connection. Use Standard Plan

2200-7 for standard details acceptable to the City. Inside drop manholes are generally not preferred.

However, they may be considered on an as-needed basis. The Design Engineer shall submit written

justification for choosing an inside drop manhole for City’s review and approval. Minimum inside

diameter for inside drop manholes shall be 5 feet. The Design Engineer shall produce associated plans

and specifications when using inside drop manholes.

3.2.3 Vented Manholes These manholes are used in flood prone areas, and in 100 year flood plains. Manholes with external

vents shall have locked, and sealed manhole lid with the vent inlet located 2 feet above the base flood

elevation. Use Standard Plan 2200-5 for more details on vented manhole.

3.2.4 Discharge Manholes This type of manhole shall be used in situations where a force main terminates in a manhole. A flow

channel shall be provided at the base of the manhole to receive flow from force main. See Standard

Plan 2200-3 for a typical detail pertaining to discharge manholes.


3-3

3.2.5 New Connections to Existing Manholes New gravity sewer connections to existing manholes shall be per the requirements stated in the City’s

Standard Specifications Sections 209 and 2200, and general engineering standards. However, direct

service line connections to existing manholes shall be limited to: one 4 inch service line per manhole.

Service line connections shall terminate at the manhole with a drop piping (see Section 3.2.2 of this

manual) to channel the flow, and the solids to the manhole invert.

3.3 Manhole Diameter Table 3-1 shows the diameter of manholes based on connecting sewer diameters:

Table 3-1 Diameter of Manholes

Diameter of Sewer, Inches Manhole Diameter, Feet1

≤15 4

>15 ≤ 27 5

>27 ≤ 36 6

>36 Special Design/As approved by City

1 – Inside diameter measured at the proposed flow line.

3.4 Manhole Flow Channel Manhole flow channels shall be made to conform as closely as possible in shape, and slope to that of

the connecting sewers. The channel walls shall be formed or shaped to the full height of the crown of

the outlet sewer in such a manner so as to not obstruct maintenance, inspection or flow in the sewers.

When curved manhole flow channels are specified including branch inlets, slopes shall be increased as

required to maintain acceptable velocities. A minimum drop of 0.1 foot shall be provided across new

manholes. In locations where pipes of differing sizes enter and exit manholes, the pipes shall be

installed such that their 0.8 pipe diameter points are at the same elevation. The channels shall be

constructed as illustrated in Standard Plans 2200-1 or 2200-2.

3.5 Manhole Castings Manhole frames and covers shall be non-rocking and shall conform to the City’s Standard Specification

Sections 209 and 2200 and the requirements of ASTM A48, Class 30. Unless otherwise indicated,

manhole frames shall be heavy-duty cast-iron type; 30-inches in diameter with a 24-inch opening.

Manhole cover inserts shall be 23 ¾-inch diameter consisting of the lettering "CITY OF SHREVEPORT"

and "SEWER". Locked and sealed manhole lids shall be used in flood hazard areas as defined by FEMA

or the City Engineer, and areas where water ponds or could pond, including traffic areas.

3.6 Manhole Access All sewer manholes outside the paved right-of-way shall have adequate vehicular access for sewer

maintenance vehicles. The manholes located within paved right-of-ways shall be located such that

adequate traffic control can be established so that maintenance functions can be performed without

incident. Design Engineer shall take into account the clearances required by the City’s maintenance

personnel, their equipment, and their vehicles.


3-4

3.7 Manhole Coatings Manhole coatings shall conform to the City’s Standard Specification Sections 209. The manhole shall

be lined on the interior with a minimum 14 mils of coal tar epoxy coating. Vented manholes and

discharge manholes shall be lined on the inside with 100% solid flexibilized epoxy protective coating

with an 80-125 mil thickness. Special coatings and coatings for rehabilitated manholes shall be per the

City’s Standard Specification Section 2220.

3.8 Manhole Height Requirements under Various Conditions including Flood Plains 3.8.1 Height of Manhole Sidewall Manhole sidewall shall be of sufficient height such that a maximum of one adjustment ring will be

sufficient to bring the manhole frame and cover to the required elevation.

3.8.2 Traffic and Street Locations The manhole rim elevations shall be at grade level for all traffic and street locations.

3.8.3 Finished Landscape Locations The manhole rim elevations shall be located at the top of the mulch in finished landscape locations.

3.8.4 Non-Finished Landscape Locations The manhole rim elevations shall be located 3 inches above grade in non-finished landscaped areas.

3.8.5 Non-Traffic Areas In non-traffic areas, the manhole rim elevation shall be limited to 2 feet above the finished grade. As

manholes in non-traffic areas may not be readily visible due to overgrowth of vegetation, bollards

(painted yellow) shall be located around them to prevent damage from maintenance vehicles. Bollards

shall be located such that it doesn’t restrict access to the manhole for routine maintenance personnel

or equipment.

3.8.6 Flood Plains In flood plains, vented manholes with external vents shall have locked and sealed manhole lid with the

vent inlet located 2 feet above the base flood (100 year) elevation. Use Standard Plan 2200-5 for more

details on vented manholes.

4-1

Section 4

Wastewater Force Mains

4.1 Design Period The design period is the length of time the capacity of the Wastewater Force Mains are anticipated to

be adequate to service its tributary area. For the City of Shreveport, the design period for Force Mains

shall be 100 years.

4.2 Wastewater Design Flows The City may have access to wastewater model(s) which predicts wastewater flow from each sanitary

sewer area. In such cases, the City will provide the design flows for the force mains. When such

information is not available, design flow shall be estimated based on population estimates and type of

development. Such estimates shall be based on assumptions described in Section 2 of this manual.

4.3 Design Calculations 4.3.1 Wastewater Force Mains The Design Engineer shall select a suitable pipe material for the application based on past experience,

common engineering design practices, and the City’s Standard Specification Sections 209 and 2100. As

stated elsewhere in this manual, preference shall be given to PVC pipe. Pipe design calculations,

geotechnical information, material and dimension ratio/pressure class selection, pertinent written

justifications and relevant supporting documents shall be included in the Design Criteria report.

4.3.1.1 Hydraulic Design of Force Mains.

The Designer shall follow the guidelines listed below:

The design of a sewer force main must be coordinated with the design of the wastewater

pumping station. In the Design Criteria report provide the range of design flows for the

planning period, the proposed design of the pumping station, system curves, hydraulic

profile(s), surge analysis, proposed force main layout, restraint calculations and the force main

as a unified system.

Develop the proposed alignment in plan and depict the changes in force main elevations in

profile.

The number of air valve installations should be minimized. This can be achieved by reducing the

number of high points and slope breaks, and by using a profile that rises continuously from the

pumping station towards the destination/transition manhole.

Forcemains shall not be connected to other existing forcemains or sewer mains unless

approved in writing by the City.

Section 4 Wastewater Force

4-2

Using the system curves, develop the Hydraulic Grade Line (HGL) profiles.

The Hazen-Williams (HW) formula shall be used for hydraulic design and sizing of force mains:

Where,

Hf = Headloss (due to friction) in feet.

Q = Flow through pipe in gpm

C = pipe roughness coefficient

L = Pipe length in feet

d = pipe inside diameter in inches.

The roughness coefficient ‘C’ varies with velocity, pipe material, size, and age. As prescribed in the TSS,

the Design Engineer shall use a ‘C’ value of 100 for unlined Iron piping, and a maximum ‘C’ value of

120 for: Polyvinyl Chloride (PVC), Polyethylene (PE), and lined Ductile Iron (DI) piping. Exceptions to

these ‘C’ values shall be submitted to the City in writing for review and approval. Suitable value shall

be selected based on the abovementioned factors.

Minor losses from bends, valves, expansions, contractions, pipe entrance, pipe discharge, and other

fittings shall be accounted for as a function of velocity head. Minor losses can be determined by the

following formula:

Where:

hm = minor loss in feet

K = coefficient for minor loss item

V = velocity in ft./sec

g = gravity constant, 32 ft./sec2

K factors can be obtained from standard hydraulic reference manuals.

System curves shall be developed for the force main, which shows the total energy losses associated

with the following conditions:

1. Maximum static head and low C factor

2. Maximum static head and high C factor

3. Minimum static head and high C factor

4. Minimum Static head and low C factor


4-3

Develop HGL profiles for the range of pumping rates (minimum, average and maximum rates) planned

for the pumping station.

For calculating friction losses in an existing force main, existing flow and pressure data, if available for

the force main and pump station can be used to determine the HW friction factor. The Design Engineer

shall also consider the future operating conditions of such existing pumping and piping systems

during design, to check that the design serves the future requirements as well.

Base the static head on the difference in vertical elevations between the wet well low operating level

and the point of force main discharge or the highest point on the force main, when this point is the

highest point in the entire pumping system.

In general, a minimum velocity of two (2) feet per second (fps) is required to maintain solids in

suspension. Velocities ranging from three (3) to three and one half (3.5) fps would be required

to re-suspend solids that have settled in the force main. Since most of the City’s pump stations

will operate intermittently or on reduced speeds, design force mains to maintain a 3 fps

velocity.

The maximum velocity in a force main shall be limited to six (6) fps. High velocities generate

high head losses, and increase the potential for severe water hammer pressures. Flow velocity

can vary in a force main, depending on the number of pumps operating in a pumping station.

Base the maximum force main velocity on the peak pumping rate anticipated during the peak

wastewater influent condition.

Where Variable Frequency Drives are used, the Design Engineer shall select a pipe size that

accommodates a range of velocities.

The Design Engineer shall submit written justification for City’s review and approval, if they

choose to use minimum and maximum velocities outside of the prescribed ranges.

The minimum size for a force main is 4-inches (diameter).

Where feasible, it may be desirable to minimize the length of the force main so as to minimize

the cost of construction and operation. Proper consideration shall be given to situations such as

utility crossings/stream crossings to avoid, and environmental impacts among others.

Limit joint deflections to 50% of the manufacturer’s recommendations.

Vertical alignment

- Uphill pumping is preferred in a force main, where the force main discharge point is at a

higher elevation than the rest of the system, so as to keep the force main under pressure.

- If an intermediate high point in the force main lies above the downstream point of the

discharge, a partial vacuum condition can be created at the high point when the force main

drains after pumps shut off, and when the HGL profile drops below the high point. When

possible, high points in the piping system shall be avoided. Where high points are

unavoidable, air release and air/vacuum valves shall be installed.

- Downhill pumping, vertical profiles which are conducive to siphoning at high points and

gravity drain/air locking in downhill pumping conditions will require special analysis to


4-4

verify proper hydraulic performance. These types of force main profiles are also conducive

to severe water hammer pressures caused by rapid velocity change in the force main

resulting from pump start up or shut down. It is therefore recommended that force main

profiles which can generate downhill flow be avoided. If downward pumping condition

cannot be avoided, then proper hydraulic performance of the force main should be verified

based on sound engineering and design principles. Consider the following, when downhill

pumping is required.

o A downward sloping force main section following a high point may not flow full

during initial line start up because the flow carrying capacity would exceed the line

filling rate. The elevation of the high point, in this case, will give the highest static head

that the pump must overcome during initial start-up.

o A downward sloping force main section may not flow under pressure at some

pumping rates during normal operation of the pumping station and when pumps shut

down. Consider if (and how) pressurized pipe flow should be achieved and

maintained.

o The extent and effects of partial vacuum condition/siphon action on force main’s

hydraulic performance.

o Trapping of air/sewer gases at the high point and the downward sloping section, and

the effects on pumping head and removal of the air/gas from the force main.

o Potential water hammer pressure due to pump shutdown or power failure.

o Evaluate the severity of water hammer pressures in the force main under the worst

case scenario, assuming power failure at the pumping station coincides with firm

pumping capacity. Upon power failure at the pumping station, severe down surge (low

pressure) can propagate throughout the entire force main, followed by upsurge (high

pressure). Examine the potential for water column separation in the force main.

Methods of water hammer pressure control and relief should be incorporated, if

necessary.

Consider the operating pressure and the surge pressure in designing restraints for the force

main.

Submit drawings, details and final hydraulic calculations to support the force main design.

4.3.1.2 Hydraulic Transients

Hydraulic transients are the time-varying phenomena that follow when the equilibrium of steady flow

in a system is disturbed by a change of flow that occurs over a relatively short time period.

Surge Control for Raw Sewage Force main: The strategies for controlling surge in raw sewage

force main/ sewage pumping stations are limited as compared to the pumping of clean water,

because some of the valves (globe and butterfly, for example are unsuitable), the reliability of

other valves (such as vacuum and air release) depends on frequent and vigilant maintenance,

and air chambers are far more maintenance-dependent for sewage than for water. However,

adequate control strategies remain and any proposed solution should be checked thoroughly.


4-5

Transients are important in hydraulic systems because they can cause rupture of pipe and

pump casings, pipe collapse, vibration, excessive pipe displacements, pipe fitting and support

deformation /failure, vapor cavity formation, cavitation and column separation. Computer

modeling is effective, but it could be expensive and time consuming. The Design Engineer shall

submit to the City, for review, all calculations pertaining to transient analysis. The following

guidelines can be used to decide if a complete transient analysis is required:

- Do Not Analyze

o Pumping station with flow rate less than 100 gal/min. Discharge velocities for such

systems is usually low and therefore transient pressures are also low.

o Pipelines with velocity less than 3ft/sec.

o Distribution networks or piping networks, as pressure in these systems are usually

dissipated at the junctions.

o Pumping systems with a static differential pressure between suction and discharge of

less than 30 ft. However, it is possible that a very low static head coupled with a

relatively high dynamic head could result in a column separation problem

- Do Analyze

o Pumping systems with a total dynamic head above 50ft if the flow rate exceeds 500

gal/min.

o For pipe diameters above 8 inches, when piping length is in excess of 1000 feet.

o Pumping systems designed for high lift that include a check valve. Flow reversal in

such systems could result in the check valve shutting (slamming) instantaneously,

resulting in high surge pressures.

o Valves on the system that are not equipped with limit switches, and are capable of

being opened or closed instantaneously.

o A system in which column separation can occur include:

Systems with high points.

A force main with air-vacuum valves.

A pipeline with a long (over 300ft.), and steep gradient followed by a long,

relatively flat gradient.

The Design Engineer is hereby recommended to consult the ‘Checklist’ as stated in

‘Fundamentals of Hydraulic Transients’ chapter of the latest edition of ‘Pumping Station Design’

by Robert L. Sanks.

Surge may occur when there is a slowdown, followed by a reversal of flow in less than Critical

Period (tc). The critical period (tc) is the roundtrip time of travel of the pressure wave from and

back to the point of flow change, and is given by the following equation:


4-6

tc = 2L/a,

Where:

L = length of force main between point of flow change and point of reflection, (ft.)

a = velocity of pressure wave, (ft./sec).

The velocity of a water hammer pressure wave depends primarily on the physical properties

of the fluid and the force main pipe material. It can be calculated using the following equation:

√

( ) (

)

Where:

K = Bulk modulus of elasticity of the liquid in psi (300,000 psi for water)

ρ = Density of the liquid in lbs./cu.ft.

E= Modulus of elasticity of the pipe in psi

D = Internal pipe diameter in inches

t= pipe wall thickness in inches

c= (1.25 - µ) for piping free to move longitudinally

c = (1-µ2) for restrained piping

c = 1 for piping with expansion joints

Where, µ = Poisson’s ratio

4.3.1.3 Required Analysis for Hydrogen Sulfide (H2S) Generation and Release

Perform a hydrogen sulfide analysis for the proposed design to determine the potential for

hydrogen sulfide gas generation. EPA’s design manual ‘Odor and Corrosion Control in Sanitary

Sewerage Systems and Treatment Plans’ is recommended for use as a reference.

Design the system piping layout to minimize the total piping lengths and pipe sizes within the

constraints of the hydraulic design criteria, so as to minimize sewage detention time in the

system. Downhill pumping conditions with a high point above the transition manholes will

potentially cause the release and accumulation of hydrogen sulfide gas at the high points. Avoid

high points in the design, if possible.

The discharge of sewage from a force main into a gravity sewer can potentially generate odor and the

release of hydrogen sulfide at the transition manhole and in the downstream gravity sewer.

Turbulence in the transition manhole should be minimized. When selecting/designing gravity sewer

pipe material downstream of transition manholes, consider the corrosive effects of hydrogen sulfide.


4-7

4.4 Location Force mains shall be located a minimum of 36 inches below grade. When traversing servitudes owned

by other agencies, the Design Engineer shall meet the minimum cover requirements set forth by such

agencies. Backlot or sidelot servitudes will not be allowed.

Wastewater Force Mains shall be located in the following locations:

Public right-of-way

Permanent access servitude with overlapping public utility servitudes

Dedicated servitude adjacent to and contiguous with the right-of-way (upon City approval)

Separate dedicated servitudes (upon City approval)

Replacement mains should be located three feet parallel to the existing mains.

4.5 Thrust Restraint Systems Force mains are subject to hydraulic thrust forces at locations where there are changes in direction or

diameter, tees, or termination at a plug or a valve. Thrust is generated by internal hydrostatic pressure

and dynamic forces. Dynamic forces are usually not significant in pipelines unless velocity head is

large in comparison with hydrostatic pressure. In high velocity pipelines, however, dynamic thrust

may be sizeable.

Forcemain joints and its fittings shall be restrained using restrained joints. Restrained joint design is

specific to the pipe material and manufacturer. The design method should consider safe bearing load

of undisturbed soil, soil cohesion, angle of internal friction, and soil unit weight. Restrained lengths

requirements for all fittings used shall be tabulated in the plans. Valves shall be considered dead ends

and restrained accordingly. A safety factor of 1.5 shall be used when calculating the restraining length.

The following technical references shall be used for calculating thrust restraint system as required:

Thrust Restraint Design for Ductile Iron Pipe, Latest Edition

AWWA M23: PVC Pipe Design and Installation, Latest Edition

Design Engineer shall submit pertinent calculations and justification (including cost savings, if any) for

an alternate thrust balancing method chosen (ex: thrust blocks), for the City’s review and approval.

4.6 Force Main Servitudes Both Construction and Maintenance Force Main servitudes will observe the same requirements for Gravity sewer. The Design Engineer

shall refer to Section 2.10 of this manual for additional information for servitudes.


4-8


5-1

Section 5

Trenchless Technologies

5.1 General Owing to the age, and condition of the existing pipeline infrastructure, and to meet future demands,

there will be a need to replace and rehabilitate the City’s sewers. Many of these sewers are located

in/near streets and public roadways or under streams. The method currently used most often for

pipe laying is the open-trench method. Open trench construction methods have several shortcomings

such as:

Health and safety concerns of workers.

Surface disturbance.

Disruption to vehicular/pedestrian traffic.

Reduction in paving life.

Potential damage to structures due to deep excavations.

Exposure of potentially contaminated soils.

Dewatering to provide stable excavation and bedding.

The use of trenchless technologies eliminates many of these potential problems. The need to replace

deteriorating underground utility infrastructure, and to expand utility services increases the need for

utility conduits to intersect roadways or cross streams. Trenchless technologies are cost-effective

alternates that provide for the installation of conduits beneath roadways or under streams with

minimal trenching (excavation). These technologies also have the potential of reducing environmental

impacts, and have the added benefit of minimizing the handling, treatment and/or disposal of

contaminated soil.

Trenchless techniques can be divided into two categories based on the project: techniques available

for pipelines renewal, and techniques for new pipelines construction. The technique most suited for

pipelines renewal projects is Cured in Place Pipe (CIPP). Techniques most suited for new pipeline

construction are: pipe boring and jacking, horizontal directional drilling and pipe bursting, among

others.

The Design Engineer shall select a trenchless option best suited for the application, by taking into

account soil conditions, costs, tolerance, land requirement (overall footprint for the operation)

amongst other factors. Certain trenchless techniques are discussed in detail in the following sections.

5.2 Boring and Jacking 5.2.1 Boring Boring is a trenchless technology typically used for installing pipes across railways, and roads. It is

widely used where rail road/paving damage, and or traffic disruption need to be avoided. Casing pipe

Section 5 Trenchless Technologies

5-2

that can be installed by boring ranges from 4 inches to 72 inches in diameter. In this method a drill

with a cutting head is used to bore holes. Typically, the cutting head is attached to an auger located

inside a casing. The boring machine generates torque, which is transmitted to the cutting head

through a flighted auger.

The boring operation requires a driving pit and a receiving pit. Typical pit sizes are 38 feet in length,

10 to 12 feet in width, with the bottom of the pit located 2 feet 8 inches below the center line of the

bore. The boring equipment including auger boring machine, augers, and cutting head is located in the

driving pit. Spoils are removed from the bore hole, at the backside of the casing in the driving pit, by

the movement of helical wound auger flights. The vertical alignment of the auger boring operation can

be monitored using a water level. Upon completion of the bore, the carrier pipe is installed within the

casing. Table 5-1 shows the Design Engineer the minimum casing sizes based on the carrier pipe size.

Table 5-1 Casing Sizes

Carrier Pipe

Diameter, inches

Minimum Casing

Diameter, inches

Casing nominal

Thickness, inches

6 12 0.344

8 16 0.375

10 20 0.406

12 24 0.469

14 30 0.500

16 30 0.500

18 30 0.500

20 36 0.562

24 36 0.562

30 42 0.625

36 48 0.688

42 60 0.875

5.2.2 Pipe Jacking Pipe jacking is a trenchless method for installing a prefabricated pipe through the ground from a drive

pit to a reception pit. Pipe jacking involves, advancing the pipe using jacks located in the drive pit.

The jacking force is transmitted through the pipe to the face of the excavation. Once the excavation is

accomplished, the spoils are transported out of the jacking pipe and shaft either manually or

mechanically.

Pipe jacking is well suited to situations where a pipeline has to conform to rigid line and level criteria.

The most common application of this technique is for installing gravity sewers, especially where the

depths are cost prohibitive when installed by open cut methods.

In order to install a pipeline using this technique, thrust (driving) and reception pits are constructed,

usually at manhole positions. The dimension and construction of a thrust pit may vary according to

the specific requirements of the drive, with economics being a key factor. Mechanized excavation may

require larger pits than hand excavated drives, although pipe jacking can be carried out from small

shafts to meet special site circumstances. A thrust wall is usually constructed to provide a reaction

against which to jack. In poor ground, piling or other special arrangements may have to be employed

to increase the reaction capability of the thrust wall. Where there is insufficient depth to construct a


5-3

normal thrust wall, for example through embankments, the jacking reaction has to be resisted by

means of a structural framework constructed above ground level having adequate restraint provided

by means of piles, ground anchors or other such methods for transferring horizontal loads. The

number of jacks used may vary because of the pipe size, the strength of the jacking pipes, the length to

be installed and the anticipated frictional resistance. A reception pit of sufficient size for removal of

the jacking shield is normally required at the completed end of each drive. The initial alignment of the

pipe jack is obtained by accurately positioning guide rails within the thrust pit on which the pipes and

jacks are laid. To maintain accuracy of alignment during pipe jacking, it is necessary to use a steerable

shield. This shield must be frequently checked for line, and level from a fixed reference. For short or

simple pipe jacks, these checks can be carried out using traditional surveying equipment. Rapid

excavation and remote control techniques require sophisticated electronic guidance systems using a

combination of lasers and screen based computer techniques.

5.3 Horizontal Directional Drilling Horizontal Directional Drilling (HDD) utilizes steerable soil drilling systems to install trenchless

pipelines from 2 inches to 36 inches in diameter. Typically, the new pipeline is constructed of HDPE

or fusible PVC, but other materials have also been utilized. In most cases, HDD is a two-stage process.

In the first stage, a pilot hole of 1 to 5 inches in diameter is drilled along the proposed pipe centerline.

This pilot hole sets the path for the following operations. In the next stage (called back reaming), a

reamer is pulled through the path set by the pilot hole (in the opposite direction) to sufficiently

enlarge the bore. The back reaming stage may require multiple passes with sequentially larger

reamers to achieve a borehole (typically no more than 150% of the final pipe OD) Once the borehole is

established, the pipeline is pulled back through the borehole using the steel drill string from the exit

side towards the drill rig. This requires that the entire length of pipe for the crossing is fused or

jointed so that the pullback is accomplished without stopping. Where space is limited, the number of

stops for intermediate fusing needs to be limited to one or two times to reduce the possibility of the

pipe “freezing” in the borehole.

The pilot hole is drilled with a surface-launched rig with an inclined carriage. An entry angle of 8 to 18

degrees with the ground is typically required in order to develop the depth needed to avoid an

obstacle (such as another utility) or to provide the minimum cover under the roadway or water body

being crossed. An exit angle of 8 to 12 degrees is preferred to reduce the bending forces and supports

needed to protect the pipe during pullback. The preferred minimum radius in feet for steel pipe,

including the drill string, is 100 feet per inch diameter of the pipe. For plastic pipe, the minimum

radius is 25-40 feet per inch diameter of the pipe. For smaller diameter pipelines, the steel drill string

size will control the minimum radius. The size of the drill rig and the drill string will increase with the

length and size of the crossing and the drilling torque and pullback tensile forces that will be required.

5.3.1 HDD for Gravity Sewers The Design Engineer should consider HDD for gravity sewers only when the pipe slope is greater than

one percent, and there is a drop of greater than 1 foot at the downstream manhole. Pipe for directional

drilling shall be HDPE (AWWA C906) with heat fusion welded joints meeting the City’s Standard

Specification’s (Section 209) requirements or fusible PVC with a minimum DR 18 (AWWA C900) or a

minimum DR25 (AWWA C905).


5-4

5.3.2 HDD for Force mains The Design Engineer shall follow the HDD requirements contained in ASTM standards, AWWA

Standards, and the manufacturer’s recommendations.

Fusible PVC will be allowed for HDD installations in nominal diameters up to 24 inches. Maximum

lengths should not exceed manufacturer’s recommendation. HDD Installations in diameters larger

than 24 inches must use HDPE as the pipe material. HDD Installations will be limited to a maximum

length that does not exceed the manufacturer’s recommendations.

Pipe used in HDD shall be capable of withstanding:

The maximum internal pressure.

The maximum external loading configuration acting independently.

The maximum pulling forces during HDD installation.

The Design Engineer shall consider dead loads, concentrated live loads, construction loads (including

tensile stress and capstan forces during pullback), and distributed loads acting on the pipe. The

minimum required safety factor is 2.0. Safety factors between 1.5 and 2.0 may be considered on a

case-by-case basis and requires approval by the City.

The Design Engineer is to consult with both an experienced HDD contractor and an engineer

experienced in HDD. The Design Engineer shall adhere to the following requirements:

Select the crossing route to keep it to the shortest reasonable distance.

Find routes and sites where the pipe can be laid out, fused and pulled in in one continuous

length.

Avoid compound curves.

Maintain a minimum cover of 15 feet over the installed pipeline at canals, bayous, creeks, and so

forth to minimize the potential for lost drilling fluids.

Avoid entry and exit pit elevation differences in excess of 25 feet.

Locate all buried structures and utilities within 25 feet area of the drill path.

Avoid design where the drill rig is directly below aboveground structures such as power lines.

Identify and layout site space to accommodate the required drill equipment, including the

drilling mud plant, and pipe size and length. (Site space varies depending on the crossing

distance, pipe diameter and soil type.)

5.3.3 Engineering Calculations The Design Engineer is referred to ASTM Standard F1962 ‘Standard Guide for the Use of Maxi-

Horizontal Directional Drilling for Placement of Polyethylene Pipe or Conduit Under Obstacles,

Including River Crossings’ for the production of the required calculations. Calculations shall be

provided to the City for review.


5-5

5.3.3.1 Pullback Calculations

The Design Engineer shall perform pullback calculations for the selected pipe material. The

calculations shall include:

Average radius of curvature for both the pipe entry and exit points.

Horizontal distance required to achieve depth or rise to the surface at the pipe entry and exit

points.

Axial bending stress.

Bending stress.

Weight of empty pipe.

Net upward buoyant force on empty pipe surrounded by mud slurry.

Pullback force acting on pipe at Points 1, 2, 3, and 4 (see Figure 5-1).

Compare axial tensile stress with allowable tensile stress during forcemain pullback at Points 1,

2, 3, and 4 (see Figure 5-1)

External static head pressure.

Combine static head pressure with hydrokinetic pressure.

Determine the reduction factor.

Calculate the critical buckling pressure due to head of drilling fluid water.

Determine the safety factor against ring collapse during pullback.

Refer to Figure 5-1 and the following assumptions when performing the pullback calculations:

- Minimum depth (H) = 15 feet

- Pipe drag on surface (this value starts at total length of pull, then decreases with time)

assume L1 = 100 feet remaining at end of pull

- Minimum distance for L3 shall be no less than 100 feet.

- Entry and exit pit shall be between 1:3 to 1:4 (rise/run)

- Assume pipe is empty during pull back.

- Hydrokinetic pressure = 10 psi

- Ovality compensation factor (for 3 percent ovality) = 0.76


5-6

Figure 5-1 Horizontal Directional Drilling Pullback

5.3.3.2 Long Term Operation Calculations

The following calculations shall be performed at a minimum for the long term operation of the pipe:

Approximate arching factor.

Approximate external earth pressure. A geotechnical engineer shall determine the earth

pressure value based on the properties of soil formation. This is an estimated value for a typical

case (or preliminary calculations) and shall not apply to the actual application.

Ring deflection.

Determine long term total external hydrostatic and buoyant soil load on pipe.

Critical unconstrained buckling pressure.

Long term operational safety factor against buckling for pipe in service.

The following initial assumptions can be made in the long term operational calculations.

However, these are only to be used for preliminary calculations and shall be replaced with

actual data collected during the geotechnical evaluation:

- Unit weight of soil = 120 pcf

- Groundwater elevation = H depth, as shown on Figure 5-1

- Unit weight of water = 62.4 pcf

- Internal angle of friction = 30 degrees

- Angle of wall friction = internal angle of friction divided by 2

- Earth pressure coefficient = 0.5


5-7

5.3.3.3 Geotechnical

The Engineer shall conduct a comprehensive geotechnical investigation to identify the following:

Type of soil.

Where rocks exist, if any.

Existence of gravely soils, loose deposits, discontinuities, and hardpan.

Soil strength, and stability characteristics.

Existence of ground water.

For crossings greater than 1,000 feet in length, borings shall be taken at 500-foot maximum

intervals. For short crossings(1,000 feet and less), three borings shall be performed, specifically

one boring near the entry pit, one boring near the exit pit, and one in the approximate middle of

the HDD path. Borings shall be made at a minimum distance of 20 feet, and a maximum of 50

feet horizontally from the bore path and shall be taken to at least 20 feet below the design depth

(H).

5.3.3.4 Land Requirements

The Design Engineer shall estimate the rig side land requirements to conduct the HDD, assuming that

the contractor will use the following equipment at a minimum: rig unit, control cab power unit, drill

pipe, water pump, slurry mixing tank, cuttings separation equipment, slurry pump, bentonite storage,

power generators, spares storage, site office (if needed), entry point slurry containment, and a

cuttings settlement pit.

The Design Engineer shall estimate the pipe side land requirements to conduct the HDD, assuming

that the contractor will use the following equipment at a minimum: cuttings settlement pit, exit point

slurry containment pit, pipe rollers, pipe product (with enough room to fuse the pipe together and

leave it on the rollers), drill pipe, and spares storage.

5.4 Pipe Bursting 5.4.1 General Pipe bursting is a technique for breaking an existing pipe with a bursting head and simultaneously

pulling a new pre-manufactured flexible pipe into the host pipe. The remains of the existing host pipe

are broken into pieces, and forced into the surrounding ground. The rear of a proper sized bursting

head is attached to the new pipe, and the front end is attached to a winch cable or a pulling rod which

is then hooked to a tool that will help keep it in-line as it progresses through the existing line. As the

bursting head assembly moves forward it is simultaneously winched or pulled forward. This action

bursts the existing pipe, and pushes the pieces of old pipe into the surrounding soil no further than the

outside edge of the bursting head as the new pipe is pulled into place. When the bursting head has

reached its destination, the stake down unit and winch cable are removed and the tool is placed into

reverse. The reverse action of the tool helps to back it out of the new line all the way to the launch pit.

The bursting head is then cut off, and removed to complete the installation of the new pipe.


5-8

5.4.2 Pipe Bursting Design The Design Engineer should adhere to the maximum depths and lengths as shown in Table 5-2 for

pipe bursting.

Table 5-2 Pipe Bursting Design

Pipe Busting Maximum Depth and Length

Pipe Diameter, inches Maximum Depth,

Feet

Maximum Length,

Feet

Maximum Upsize

Pipe Diameter

≤ 12 12 350* 18

>12 ≤ 18 18 450* 24

* For gravity sewer lines, the maximum length shall be the length between two consecutive manholes. Design Engineer shall verify feasibility of pipe

bursting.

Pipe bursting is generally not allowed in the following cases:

Sewers deeper than 18 feet.

Pipes larger than 24 inches.

Upsizing more than two pipe diameters or 1.5 times the diameter of the host pipe.

Lengths greater than 450 feet.

When pipe sags more than 20 %.

When pipe sags extend more than 8 feet.

When pipe is located under railroads, buildings, or structures.

When pipe is located in a rock trench.

Pipes encased in concrete.

Piping with significant number of valves.

Piping that include steel joint bands.

The Design Engineer shall perform soil investigation activities such as soil borings, standard

penetration tests, unconfined compression tests, moisture content tests, and groundwater readings to

determine the feasibility of pipe bursting. Compressible clay soil is ideal for pipe bursting. Special

attention shall be paid to pipe diameter when the replacement pipe is HDPE.

Most brittle pipe materials such as clay, non-reinforced concrete, PVC, cast iron, and asbestos-cement

pipe make good candidates for pipe bursting. Steel, and ductile iron pipes are not good candidates for

pipe bursting due to their strength and ductility. Inter- seam process shall not be allowed.

Owing to their continuity, flexibility and versatility, HDPE is preferred for pipe bursting and it is

preferred over other pipe materials. Pipe joints are to be fused and cooled prior to bursting. Other

piping material can also be used for pipe bursting when space is limited.


5-9

Minimum cover of the new pipe shall be:

10 times the burst displacement.

3 times the new pipe diameter.

4 feet below the ground surface.

3 feet clear from the nearest utility.

The Design Engineer shall consider the surrounding utilities that can affect the location, and size of the

pit(s) for pipe bursting. Any utilities that may interfere or may be damaged by the burst shall be

located, and exposed prior to the burst. Pipe bursting lubricants shall always be used to reduce

friction and relaxation shortening. The minimum relaxation period shall be 24 hours. As sewer depth,

pipe size, degree of pipe up-sizing and burst lengths increase, the relaxation period shall increase.

Open cut replacement shall be considered when a line to be pipe bursted has 4 laterals every 200 feet.

5.4.3 Crushed Liner Process A variation on the pipe bursting process is the crushed liner process. In this method, the pipe bursting

head has a cutting head integrated with a pneumatic hammer which supports the destruction and

crushing of the old pipe. The exhaust air of the hammer is use to convey the crushed pipe pieces from

the region of the cutting head into the conveying screws. This material is then moved through the

pipe into the launch pit for disposal.

5.5 Cured in Place Pipe 5.5.1 General The cured-in-place pipe (CIPP) lining process is used for rehabilitating existing sewer pipes without

having to replace the pipes.

CIPP uses a felt liner that is impregnated (typically under a vacuum) with thermoset resin which is

expanded with air or water under pressure to form tightly against an existing pipeline. The liner can

be cured with hot water, steam/hot air, ultraviolet lights (UV) or ambient conditions (time). CIPP has

the inherent advantage of conforming to almost any shape of pipe, making them suitable for relining

non-circular cross-sections, and resolving pipe defects.

CIPP creates a close-fit “pipe-within-a-pipe” which has quantifiable structural strength, and can be

designed to suit various loading conditions. The ring-stiffness of the liner is enhanced by the restraint

provided by the host pipe and the surrounding ground. ASTM F1216 can be used as a guideline for

design of the wall thickness of gravity flow, circular CIPP installations. Other more recent publications

can also be utilized for proper design of the liner. Other design methods including WRC manuals of

practice can be used for non-circular designs and pressure pipe applications. The assumptions

selected for the design should only be chosen by an engineer experienced in the proper design of CIPP.

Liner’s structural design should enable it to withstand all of the live and dead loads. Professional

judgement is also recommended to avoid an over-designed system which can result in waste of money

or cause installation problems. Table 5-3 lists the size and length limitations for both methods.


5-10

Table 5-3 CIPP Method Limitations

Item Acceptable Parameter

Typical Application Wastewater Main, Gravity or Force main

Host Material PVC, Clay, DI

Liner Pipe Size – Inverted 8 inches to 108 inches

Liner Pipe Size – Winched 8 inches to 100 inches

Liner Material ASTM D5813, Specify Class I,II or III Thermoset Resin/ Fiber

Composite

Max Installation Inverted 3000 feet

Max Installation Winched 1500 feet

5.5.2 CIPP Guidelines CIPP should be considered when:

There is only moderate or less active infiltration into the pipe.

Where pipe joint offsets are 1 inch or less for small diameter pipes.

Where there is minimal structural deformation from longitudinal and circumferential cracking.

Where root intrusion can be removed through interior cutting.

Where sags in pipelines are less than 25 percent of pipe diameter. Sags should be repaired if

they have significant impact on the flow, sewer capacity or debris is getting trapped frequently

in the sag.

Where all protruding service laterals have been properly repaired.

Where point repairs exhibit minimum settlement, flow restriction, offset or structural

deformations.

Where there is severely exposed surface aggregate.

CIPP should not be considered when:

If major infiltration/inflow is observed in the pipe that can’t be sealed with a chemical grout or

other means.

When pipes have holes with visible voids in the soil surrounding the pipe.

When structural damage has occurred such that a camera cannot pass through the defective

pipe section.

Where excessive cleaning is needed which may result in collapse of the pipe.

Multiple point repairs are required before installation, and 25% or more of the existing pipeline

must be replaced.


5-11

5.5.2.1 Lateral Repairs

Additional considerations are required for the existing service connections or laterals to meet the

goals of each project with regards to infiltration reduction, lateral blockages, intruding taps, defective

taps, root intrusion and other similar issues. The laterals may need to be replaced or relined with

CIPP to meet the goals of the project and customer needs.


5-12


6-1

Section 6

Wastewater Lift Station Design

The primary objective of this section is to provide dependable wastewater pumping facilities, and to

provide reliability in conformance with EPA Class I reliability standards for mechanical and electrical

components and alarms.

6.1 Wastewater Design Flows Projected wastewater inflow to a lift station shall be calculated using the procedure outlined in

Chapter 2 of this manual and the City of Shreveport’s Master Planning Document. As stated in Section

2.1, it shall be the Design Engineer’s responsibility to verify any data provided by the City based on

detailed survey information and field review of the project collection system, note any potential

inconsistencies in the provided flow data and present them to the City. In instances where

hydraulic/hydrology models are not available to the City, the design engineer shall provide the

following information:

Total acreage in the lift station watershed.

Total population and acreage of existing developments to be served by the lift station.

Total population and acreage of proposed developments to be served by the lift station.

Average day and peak hourly inflow to the lift station.

Minimum force main size shall be 4 inches in diameter. Lift stations are permitted only for areas or

basins with 200 households or more. Gravity sewers shall be used for areas not meeting the

aforementioned criteria.

6.2 Number of Lift Station Pumps A minimum of two pumps shall be installed in each lift station, with one pump serving as a standby

unit. For duplex pump stations, each pump shall be capable of pumping the peak hourly flows with

one pump out of service. For larger pump stations, the ability to pump the peak hourly flow rate shall

be provided with the largest pump out of service.

6.3 Wetwell Design The wetwell design, including wetwell geometry, shall adhere to the latest version of the Hydraulic

Institutes Standards, and Ten State Standards. The sizing of the wetwell is dependent on whether the

pump drives are variable speed or constant speed.

6.3.1 Wetwell Volume for Variable Speed Pumping Where variable speed pumps are used, the pump station firm pump capacity is used for wetwell

design. The maximum pumping capacity with one out of service is the pump station’s firm capacity.

The Design Engineer shall take into account the minimum submergence recommended by the

Section 6 Wastewater Lift Station Design

6-2

manufacturer in selecting the ALL PUMPS OFF elevation. The Design Engineer shall also consult the

City’s Water and Sewerage personnel during design to establish wetwell operation set points.

6.3.2 Wetwell Volume for Constant Speed Pumping For constant speed pumps, the PUMP OFF elevation shall be determined using the following equation:

Pump Off Elev = Ve/Aw

Where Ve is the effective pumping volume in cubic feet, and Aw is the wet well cross sectional area in

square feet. The effective pumping volume may be estimated as follows:

Ve = Q*tmin/7.481*4

Where Q is the design wet weather flow rate in gallons per minute, Ve is the effective pumping volume

in cubic feet, and tmin is the minimum time interval in minutes allowed in one pumping cycle.

Minimum cycle time (tmin) is calculated as follows:

tmin = 60min/No of cycles per hr

The time within one pumping cycle shall be limited in order to prevent motor insulation failure due to

overheating. When a motor starts, the inrush current may be significantly higher than normal

operating current, resulting in significant heat generation. Hence frequent motor starts do not give the

motor adequate time to “cool down” between starts. The Design Engineer shall also refer to NEMA

standards.

Pump cycle times shall generally be in accordance with the manufacturer’s recommendation, or

limited to a minimum cycle time of 15 minutes (at design flow), or pursuant to the Ten State

Standards, in the absence of a manufacturer’s recommendation. For cycle times less than 15 minutes

at design flow, the Design Engineer shall obtain written verification from the pump and motor

manufacturer that cycle time is acceptable. Pump cycle times shall not exceed manufacturer

recommendations and NEMA standards.

Wetwell storage volume shall be such that detention time is less than 30 minutes at dry weather flow,

per the Ten State Standards, to minimize septic conditions and odor generation. For low flow

conditions, controls shall cycle the pumps at a minimum of once every 30 minutes.

6.3.3 Wet Well Appurtenances The Design Engineer shall determine if bar screens and basket screens are required for the pump

station. Mechanical bar screens shall not be used. Screens shall be in accordance with Chapters 40 and

60 of the TSS.

6.4 Lift Station Design Calculations and Procedures Lift station design calculations shall commence by establishing inflow to the lift station as outlined in

Section 6.1 of this Chapter, followed by hydraulic analysis of the pumping system. A suitable pump

shall be selected based on the application, and it shall be verified against the forcemain sizing, fittings

used, solids content of the fluid, and head requirements.


6-3

6.4.1 Pumps Selection Pumping selection includes choosing the type of pump for the application (for example, non-clog

pumps for raw sewage, recessed impeller pumps for gritty flows etc.), sizing the pump based on

calculated flowrates and head losses, developing a range of system curves, followed by verifying the

pump curve against the system curves. Where practical or required, pump selection shall include non-

overloading motors. For pumps operated on variable frequency drives, the reduced speed curves shall

also be verified against the system curve. Special attention should be given to the pump selection

when the pump station is discharging into a force main which serves other pump stations.

6.4.1.1 Pumps

The most efficient pump for the anticipated flows, during all phases of expansion shall be selected.

The pump configuration shall be parallel unless otherwise approved by the City. Pump stations shall

include a minimum of two pumps, each capable of handling the peak wet weather flow. For

installations with more than two pumps, the pump station must be capable of handling the peak wet

weather flows with the largest pump (based on capacity) out of service.

As pump station flows vary over time, the design engineer shall design the pump station to handle

such flows from initial startup to ultimate build-out. The pumps shall be designed to operate

efficiently at average flows while providing enough capacity to handle anticipated wet weather peak

flows.

6.4.1.2 System Head Curve

The Design Engineer shall prepare a set of pump curves to simultaneously represent the System Head

operation under a wide range of situations using the Hazen Williams formula.

Where,

Hf = Headloss (due to friction) in feet.

Q = Flow through pipe in gpm.

C = pipe roughness coefficient.

L = Pipe length in feet.

d = pipe inside diameter in inches.

The Design Engineer shall analyze pump performance at the following conditions:

Hazen William’s ‘C’ value selection shall be in accordance with Section 4.3.1.1 of this manual. Owing to

varying static head conditions and forcemain losses, the Design Engineer shall generate four system

curves to address the following conditions:

1. Low Static Head, Low ‘C’ value. 2. Low Static Head, High ‘C’ Value 3. High Static Head, Low ‘C’ Value 4. High Static Head, High ‘C’ Value


6-4

System curves at these conditions, in conjunction with the pump curve(s) will define the operating

range for the pump(s). In addition, the Design Engineer shall also develop the Net Positive Suction

Head Available (NPSHA) curve.

The Design Engineer shall provide a hydraulic profile of the entire pump station/forcemain system,

and this profile shall show the hydraulic grade-line from the pump station to the discharge location(s).

Where the forcemain contains intermediate high points, the Design Engineer shall analyze if this point

becomes the controlling discharge elevation under certain flow conditions. The Design Engineer shall

provide detailed calculations to the City for information and review.

6.4.1.3 Pump Curves

Once the system curve is developed, several types of pumps can be analyzed to ascertain which pump

curves best fit the system curves. Most manufacturers provide pump curves with the total dynamic

head (TDH), efficiency, Net Positive Suction Head Required (NPSHR), and power input plotted against

the flow rate. Pump curves shall be defined by: design point, reduced speed design point (where

applicable), shut-off head, and run out point. These pump manufacturer curves can be plotted against

the system curve to verify the pump’s operating region. Pumps with steeper curves shall be selected

over pumps with relatively flat curves. Additionally, the most efficient pump shall be considered.

In cases where multiple pumps are required to produce the necessary flow at the required head,

parallel pumping curves shall be generated and verified against the system curves. This exercise must

be performed for new designs as well as modifications to existing lift stations. The pump selection

comprising pump type, manufacturer, model number, size, impeller size, flow in gpm, TDH, efficiency,

Net Positive Suction Head (NPSH), Horse Power (HP), Revolutions Per Minute (RPM) and pump head

curves plotted with the system head curves and calculations for each pump must be submitted to the

City for review. The total cycle times for Average Daily Flow (ADF) and Peak Hourly Flow (PHF)

(number of minutes “on” and “off”) shall also accompany the submittal.

If Variable Frequency Drives (VFDs) are used, the engineer shall prepare reduced frequency curves.

Curves shall be provided for the following percentages of full speed: 100, 90, 80, 70, and 60. It is

recommended that pumps not be operated on VFDs below 40 percent of its rated speed to prevent

recirculation and churning. The minimum flow rate at which the pump is capable of continuously

pumping wastewater should also be identified.

6.4.2 Force Main The Design Engineer shall refer to Section 4.3.1 Wastewater Force Mains for guidelines and other

design considerations.

6.5 Submersible Sewage Pump Station A submersible sewage pump station includes a wet well, submersible pump(s), valves and an

electronic pump control system. The wet well for submersible pump should follow the procedures

outlined in Section 6.3. Regardless of the capacity of the wet well, the wet well configuration and

placement and spacing of the pumps shall comply with the Hydraulic Institute guidelines to prevent

turbulence and vortexing at the pump inlet.


6-5

6.5.1 Construction Submersible pumps and motors shall be designed specifically for raw wastewater use, including

totally submerged operation during a portion of each pumping cycle and shall meet the requirements

of the National Electrical Code (NEC) for such units. An effective method to detect shaft seal failure or

potential seal failure should be provided. Small pre-fabricated submersible pump stations are

available with pumps, and motors pre-configured into a single well. Where possible such pre-

fabricated pump stations shall be used.

All fixtures and fasteners, including guide rails and brackets shall be constructed of Type 316 stainless

steel. Aluminum access hatch(es) with safety grating must be provided above the pumps in the top of

the wet well, and for the valve and flowmeter vaults, and shall have adequate clearance to safely and

easily remove the pumps.

6.5.2 Wet Well Coatings The interiors of the lift station wet well shall be coated or lined using an appropriate coating or lining

material to the required thickness as detailed in the City’s Standard Specifications and shall be

completely resistant to hydrogen sulfide and sulfuric acid. Coating or lining materials shall be subject

to the approval of the City.

6.5.3 Removal of Submersible Pump These pumps shall be capable of being removed or replaced without the need for: personnel to enter

the wet well, dewatering of the wet well, or disrupting any piping in the wet well, so as to maintain

continuity of operation of the other units. The access hatches shall also be adequately sized to meet

these requirements.

6.5.4 Electrical Equipment Electrical systems and components such as control and alarm circuits must be designed to provide

strain relief, and to permit disconnection from outside the wet well. Terminals and connectors must

be protected from corrosion by location outside the wet well or through use of watertight seals. Three

phase power shall be used where available.

The Control Panels shall be enclosed in Type 316 Stainless Steel NEMA 4X enclosures and shall include

adequate space for mounting of the controls and instrumentation as required. The motor control

center should be located in a clean dry area, be readily accessible and be protected by a conduit seal or

other appropriate measures meeting the requirements of the National Fire Protection Association

(NFPA) Code 820 for Wastewater Facilities, to prevent the gases prevalent in the wet well from

entering the control center. The seal shall be located in a manner such that the motor may be

removed and electrically disconnected without disturbing the seal. When such equipment is exposed

to weather, it shall meet the requirements of weatherproof equipment (NEMA 3R or 4). Electrical

design shall include lightning and surge protection.

The main breaker shall be a NEMA 4X enclosure, and shall include a minimum of sixteen (16) breaker

spaces, sized in accordance with the lift station capacity, and other electric connections to be installed

on site. Individual connections shall be powered by separate breakers (ex: lights, and radio shall be

powered by two separate dedicated breakers). The main breaker shall meet the requirements of the

NEC.


6-6

Pump motor power cords shall be designed for flexibility and serviceability under conditions of extra

hard usage and shall meet the requirements of the NEC standards for flexible cords in wastewater

pump stations. Ground fault interruption protection will be used to de-energize the circuit in the event

of any failure in the electrical integrity of the cable. Consider base flood elevations when locating

electrical equipment. Special consideration should be given to the power cord insulation to verify it

can with stand the wet well gases, including odor control chemicals/equipment.

Power cord terminal fittings shall be corrosion-resistant, and constructed in a manner to prevent the

entry of moisture into the cable, shall be provided with strain relief appurtenances and should be

designed to facilitate field connections. Design for lift stations without buildings shall include covers

for electrical, telemetry and control units. Covers shall be rated for outdoor service and shall include

sunshields to facilitate easy reading of Light Emitting Diode (LED) displays. Equipment placed

outdoors shall be rated for such service and shall be sized for ambient temperatures and cooling

requirements.

6.5.5 Valve Vaults Separate valve vaults may not be required for packaged lift stations that include their own valve

enclosures, the Design Engineer shall check manufacturer requirements during design to confirm

location of valves. For all other lift stations, required valves should be located in a separate valve

chamber, valves shall not be located inside the wetwell. Provisions shall be made to remove or drain

accumulated water from the valve chamber. The valve chamber may be dewatered to the wet well

through a drain line with a gas and water tight valve.

Valve vaults shall be sized to accommodate the force main pipe size, and associated valves and fittings.

A minimum 2 feet clearance between inside walls of the vault and all valves/fitting shall be provided.

6.6 Dry Pit Pump Station The Wet Pit of this type of station is the wetwell. The wetwell contains the level control and suction

piping for the pumps. The dry-pit including the superstructure shall be completely separated from the

wet well. Common wall must be gas tight. Each pump must have individual suction pipe to the wet

well. Isolation valves should be located both between the pump and the wet well and downstream of

the discharge check valve. At a minimum, pumps and its appurtenances shall be designed to withstand

pumping conditions (ex: grit, solids, rags), service conditions (ex: presence of H2S gases, highly

corrosive sewers). Pump shall also be equipped, at a minimum, with suitable coatings, moisture

detectors, temperature detectors, appropriate seals, and wear rings (where required).

6.7 Valves for Pump Stations The configuration of valves is dependent upon the lift station’s design capacity. Suitable isolation

valves shall be placed on the pump suction and discharge lines where appropriate. Check valves shall

be placed on the discharge line of each pump. The isolation valves shall be full port eccentric plug

valves with elastomeric-coated plug and lever operators. Eccentric plug shaft shall be installed

horizontally, with plug stored in the top position when valve is OPEN, to minimize potential for grit

accumulation in valve seat or shaft bearing. Valves shall be laid such that the plug is on the “top” of the

body when fully opened. Only full-body flanged check valves shall be used. Cushioned swing-type

check valves with an outside lever and spring or weight unit shall be provided, so operators can see

which valves are OPEN. Flow velocities through check valves shall not exceed 10 fps. Check valves

shall be mounted at elevations that permit servicing from the floor without scaffolds or ladders. All


6-7

valves shall be shown on the drawings, and shall be of the same size as the pipe in which the valve is

situated, unless otherwise noted. Valves shall be capable of withstanding test pressures (usually 1.5

times the working pressure) and the pressure generated by a water hammer.

Electric operators shall be provided for valves 20 inches and larger. The operators shall include local

OPEN/CLOSE controls that can be secured to prevent unauthorized operation of the valve.

6.8 Air Release Valves Air relief, air-vacuum release, or combination air release and vacuum valves shall be of a type and

brand manufactured for wastewater service, and shall be provided at critical locations in the pump

station and force main. The valves shall serve to prevent air being captured inside the piping system,

or prevent collapse of the piping system due to vacuum conditions. Each valve shall be sized with the

adequate orifice size suitable for the volume of air to be admitted or released. Each valve shall be

provided with an isolation valve. An insulated coupling, ball valve, and pipe union shall be provided on

each assembly to allow maintenance and removal of the air valve. The air-release valve discharge

piping in pump stations shall be piped to the station’s wet well.

6.9 Emergency Bypass Connection The Design Engineer shall design the lift station piping to permit an emergency bypass connection to

allow pumping of the lift station wet well in case of total pump station failure. The connection shall

include a quick connect coupling for connection to the emergency bypass pump. Bypass connection

shall be designed with an isolation valve. Locate bypass connection so as to provide ample space for

access by bypass trucks/trailers.

6.10 Flowmeter Magmeter shall be located in the superstructure of dry pit pump stations, or in a dedicated concrete

vault in case of wet pit pump stations. The magmeter display shall be located in the superstructure for

dry pit pump stations. Displays placed in the open shall be housed in an assembly that includes a

sunshield. The Design Engineer shall locate the magmeter such that all manufacturer recommended

upstream and downstream clearance requirements are met, while maintaining sufficient clearance for

maintenance operations. All magmeter installations shall include digital display/readout to indicate

flows in gallons per minute (gpm), signal from the magmeter shall be transmitted to the SCADA as

indicated elsewhere in this document. Magmeters are to be located such that they are not installed on

downcomer pipes.

6.11 Pressure Gauges All new pump stations shall include a suction (where possible) and discharge pressure gauge suitable

for wastewater service. Pressure transducers (also known as pressure transmitters) shall be used in

pump stations where it is required to transmit pressure readings to the City’s SCADA system.

6.12 Hoisting and Lifting Equipment For pump weighing 1.5 tons and above, include in design, a means for the removal of pumps and other

heavy equipment located at the pump station in coordination with the City’s Wastewater and

Sewerage personnel. Lifting equipment shall be sized to remove the heaviest equipment with a 2x

safety factor. Lifting distance (height) shall account for complete removal and loading of the


6-8

equipment on a truck bed. Lifting mechanism shall be completely motorized and shall be in

accordance with the City’s Standard Specification Section 2800.

6.13 Odor Control When designing odor control system for the lift station, the Design Engineer shall obtain all relevant

data from the City (if available), previous studies (if available) or by field measurement. In general,

odor control systems are to be designed to lower the Hydrogen Sulfide (H2S) concentration to meet

Department of Health and Hospitals’ (DHH)permit requirements. Various techniques and

methodologies are available to achieve odor control as listed in the EPA’s design manual – ‘Odor and

Corrosion Control in Sanitary Sewerage Systems and Treatment Plants’. All relevant calculations shall

be documented in the Design Criteria Report.

For lift stations that will be operated infrequently, incorporate a compressed air system (with

diffusers), in consultation with the City, to effect odor control. The air pump flowrate, in cubic feet per

minute (CFM) shall be sized based on the volume of the sewer in the wetwell to be mixed. The Design

Engineer shall use a mixing air flow rate of 20 CFM/1000 Cu.Ft to 30 CFM/1000 Cu.Ft as

recommended by the Ten States Standards. The pressure rating for the air pump shall include head

losses in the piping/tubing, losses due to fittings, valves, air filters etc., and the water level in the

wetwell. The diffuser for such systems shall be located at appropriate locations to minimize air

entrainment into the pumps. The air pump assembly, including its filters, silencers etc. shall be housed

in a suitable enclosure.

For all other lift stations, the Design Engineer shall recommend a suitable odor control technology or

methodology based on controlling parameters for each lift station, commonly accepted engineering

practices, past experiences, and City preferences.

6.14 Pump Station Emergency Operations 6.14.1 General The design engineer must evaluate the need for backup power at a wastewater lift station for each

specific location. The aim of emergency operation is to prevent the discharge of raw or partially

treated sewage to any waters and to protect public health by preventing backup of sewage and

potential discharge to basements, streets and other public and private property. The Design Engineer

shall discuss the need for, and type of emergency pumping equipment with the City’s Water and

Sewerage personnel during design.

6.15 Lift Station Controls Lift Station controls shall be based on the pump size (Hp) as listed in Table 6-1. This classification

system is not universal and its usage is limited to this manual, and other pertinent documents (ex: lift

station specifications). The Design Engineer shall consult the City, and incorporate the City’s control

system protocol when updating /editing specifications for lift stations and control systems.

Table 6-1 Lift Station Size Classification

Individual Pump Size (Hp) Lift Station Classification

< 15 Hp Small

≥15 Hp < 25 Hp Medium

≥25 Hp Large


6-9

Various control elements for the lift stations are detailed in Table 6-2.

Table 6-2 Lift Station Control Elements

Lift Station Controls Small Lift Station Medium Lift Station Large Lift Station

VFD SC IN Y

Float Ball Controls Y Y N

Float Ball Backup System SC IN Y

Human Machine Interface (HMI) SC IN Y

Programmable Logic Control (PLC) SC IN Y

Soft Starts Y Y N

SC – Special Cases only. Provide written justification for City review; IN – If Needed. Based on Design Engineer’s

evaluation and recommendations; Y – Yes; N - No

6.15.1 HMI Signals and Alarms Signals and alarms at each lift station vary based on the lift station size. See Table 6-3 for HMI signal

and alarm parameters. Alarms shall be transmitted to the operations staff by means of the radio

telemetry system. Consult City during design to finalize outputs to the SCADA system.

Table 6-3 Lift Station HMI Signals and Alarms

HMI Signals And Alarms Small Lift Station Medium Lift Station Large Lift Station

Operation Mode (primary/ backup) SC IN Y

Level And Alarm Set Points SC IN Y

Pump Current (amps) SC IN Y

Pump Speed (Hz) SC IN Y

Pump Run Time (Hours) Y Y Y

Hand/Off/ Auto operation Y Y Y

Pump Over Temperature Y Y Y

Pump Moisture Sensor Y Y Y

Pump Overload Y Y Y

Seal Water System (If applicable) Y Y Y

Wet Well Level SC IN Y

Alarm History SC IN Y

High Wetwell Level Y Y Y

Low Wetwell Level Y Y Y

Flowmeter Reading SC IN Y

Pressure Transmitter Reading (psi) SC IN Y

Primary Power Fail Y Y Y

Sump Pump Status IN IN IN

High Sump Alarm IN IN IN

Intrusion Alarm (where applicable) Y Y Y



6.15.2 Telemetry System 6.15.2.1 General

Include Remote terminal units (RTUs) for each lift station in the system. The City prefers that RTU and

associated SCADA equipment are from a single manufacturer or vendor.


6-10

6.15.2.2 Hardware

The master, and the RTUs will be the same hardware with I/O selected per device. The unit shall be

field expandable for the addition of alarm, status, control and analog inputs and/or outputs. All

firmware shall be non-volatile (memory) with automatic restart after power failure. An on board

watchdog timer shall be included.

Basic input/output capabilities of the unit shall include ten (10) digital inputs, ten (10) digital outputs,

four (4) analog input and two (2) analog outputs. Digital input shall be optically isolated and meet

IEEE 2.5KV surge suppression. Digital outputs shall be Relay Form A250 VAC, 6 Amp load; 125 VAC;

20 VDC, 5 Amp load @ 30 VDC. Interface of digital output to field devices shall be through isolated

relay contacts. Contacts shall be rated for 3 amperes at 240 VAC.

The RTU shall consist of the following:

1. NEMA 4X Stainless Steel Enclosure

2. Control Power Circuit Breaker

3. Controller with 3 communication ports

4. RADIO as recommended by SCADA Consultant

5. Power supply with battery backup for 8 hours

6. TVSS on Incoming service

7. Lightning Protection for antenna

6.15.2.3 Diagnostics

Include internally mounted Light Emitting Diode (LEDs) for indication of power on, CPU run, carrier

detect, receive data, request-to-send and transmit data.

6.15.2.4 Requirements of Power

The RTU will be powered by a 12-volt power supply. A sealed 7 Amp/Hr gell cell 12-volt battery and

charger will be supplied to power the entire RTU during emergency power outage conditions.

6.15.2.5 Communications

The SCADA System shall be capable of supporting Ethernet connectivity and TCP/IP communication

protocols.

6.15.2.6 Radio System

The telemetry signals shall be transmitted/received over a radio system operating in a half-

duplex mode on a single VHF Frequency Modulation (FM) radio frequency.

The radio telemetry system shall include an antenna for each site as required to achieve the

overall communications requirements of the system. Antennas shall be directional or omni-

directional as required and suitable for outdoor environments. They shall be of all aluminum

construction and rated to withstand as least 100 MPH winds with ½ inch radial ice.


6-11

Adequate lengths of RG213A/U coaxial cable shall be provided for connection of the antenna to

the radio transceiver at each site. Splicing of cable shall not be allowed. The transmission line

shall be terminated only in connectors rated for the required service. A lightning arrestor shall

be placed between the transceiver and coaxial cable.

Unless specifically stated, the antennas shall be attached to a separate pole. Particular attention

shall be given to the correct installation of the antennas to give adequate protection from

nearby lightning strikes by providing a low resistance DC path to ground. Instructions for

installing these antennas shall be given to the contractor to facilitate reliable operation.

Design shall include mounting masts or poles as required to support the antennas at the

elevations and orientations required. Masts and poles shall be suitable for outdoor

environmental conditions, provide adequate support and protection for transmission lines and

shall be complete with all necessary mounting accessories.

Consult the City’s Water and Sewerage personnel regarding preferred radio systems.

Minimum acceptable technical and physical specifications of the directional antenna shall be as

follows:

Type: 3 element Yagi, with a forward gain of at least 10 dB

Front to back ratio: 20 dB

Lightning Protection: Direct ground

Feed point method: Weatherproof gamma match for coaxial feed line

6.15.2.7 RTU Outputs to SCADA

Lift station RTU Outputs to the City’s SCADA system shall also be based on the lift station size. See

Table 6-4 (below) for RTU outputs. Consult City during design to finalize outputs to the SCADA system.

Table 6-4 Lift Station RTU Outputs

RTU Outputs Small Lift Station Medium Lift Station Large Lift Station

Wet Well Level (Analog) SC IN Y

Pump Current (analog) SC IN Y

Pump Speed (analog) SC IN Y

Flowrate (analog) SC IN Y

Discharge Pressure (psi) SC IN Y

Power failure (digital) Y Y IN

Pump running (digital) SC IN Y

Pump run time (hours) SC IN Y

Pump Over Temperature (digital) SC IN Y

Moisture Sensor (digital) SC IN Y

Motor Overload (digital) SC IN Y

VFD fault SC IN Y

Pump in ‘Auto’ (digital) SC IN Y

Wet well transmitter failure (digital) SC IN Y

High level alarm (digital) Y Y Y

High sump alarm (digital) IN IN IN


6-12

RTU Outputs Small Lift Station Medium Lift Station Large Lift Station

Float position- High wetwell level SC IN Y

Float positions - Low wetwell level SC IN Y

Operations on float ball backup (digital) SC IN Y

Communication status (digital) Y Y Y

Intrusion alarm status (digital) Y Y Y



6.16 Lift Station Siting and Access Lift stations shall be located in public right-of-way or in a dedicated servitude on property owned by

the City or property donated to the City, such that they are easily accessible by the City maintenance

vehicles and supply trucks; and as far as possible from residential areas. Locate lift stations at a

minimum of 150 feet away from any existing or proposed residential dwelling.

Lift stations shall be served by a permanent access road that is located in the public right-of-way. For

lift stations with onsite chemical storage for odor control, access roads shall be designed to provide

sufficient turning radius for chemical supply trucks. The finished access road shall be constructed with

at least 3 inches of asphaltic concrete with a crushed aggregate base, or 8 inches of concrete with a

crushed stone base, or crushed rock as approved by the City. Base material and compaction

requirements for the access road shall be based on geotechnical information for the site. The access

road must be located above the 25-year flood elevation.

The site shall be located a minimum of 2 feet above the 100-year flood elevation, and shall be designed

with site grading devised to prevent storm/rain water ponding or erosion. Areas immediately

adjacent to the lift station shall be graded such that storm water doesn’t run across the lift station or

deposit runoff or debris on the lift station. Design all electrical and instrumentation control panels to

be mounted a minimum of 3 feet above the 100-year flood elevation.

A potable water line with a freeze proof hose bib shall be provided within the lift station premises. The

water line shall be designed with a suitable backflow prevention device, and shall be located a

minimum of 25 feet away from the outer wall of wetwell.

The lift station site shall be secured by a fence with gate(s) suited to the locality (ex: decorative

fence/wall for a lift station located in a City park), therefore type of fence and gates shall be decided in

consultation with the City.

7-1

Section 7

Water Distribution Mains

7.1 Potable Water Design Flows The City’s water system should be able to supply water at all times, at rates that oscillate over a wide

range during different hours of the day, and times of year. Per capita usage can fluctuate considerably

depending on the type of population served (Industrial/Domestic/Commercial). The most important

flows pertaining to the design of a potable water system are as follows.

7.1.1 Annual Average Daily Flow The annual average daily Flow (AADF) is the total quantity of flow delivered each day to the water

distribution system in a year divided by the number of days in a year, usually 365 days.

7.1.2 Peak Daily Flow The peak daily flow (PDF) is the maximum quantity of water that can be used in any day of the year. It

is also referred to as maximum daily flow. Raw water transmission and water treatment facilities are

typically sized to meet the peak daily demand.

7.1.3 Peak Hourly Flow The peak hourly flow (PHF) is the quantity of flow delivered during the highest water use hour.

7.1.4 Water Main Sizing Water mains and extensions shall be sized to accommodate the sum of peak daily demand (typically

between 1.5 to 1.8 times AADF) and fire flow demand or peak hour demands (typically between 2.0 to

3.0 times AADF), whichever is larger.

7.2 Fire Flow Fire flow (FF) is the amount of water available in the system for combating a fire at designated

locations throughout the community. The minimum fire flow rate, pressure and duration shall be

estimated based on the information from Fire Marshall’s office or the Insurance Services Office (ISO)

guidelines.

7.2.1 Peak Flow The peak flow (PF) is the ultimate flow that can be delivered into the system instantaneously. It shall

be the sum of peak daily flow plus the fire flow rate (PF = PDF + FF) or the PHF, whichever is greater.

7.3 Transmission Mains and Distribution Mains Transmission lines are conduits that carry large volumes of water from one point to another without

intermediate service connections. Distribution mains are smaller pipelines that deliver treated

potable water to the customers.

Section 7 Water Distribution Mains

7-2

For the purposes of this manual, all water mains in the City‘s system that are 16 inches and larger in

diameter are categorized as transmission mains. All water mains 14-inches and smaller in diameter

are classified as distribution mains.

Service connections on transmission mains are prohibited unless approved by the City. Approved taps

on transmission mains shall be a minimum of 2 inches in diameter.

7.4 Water System Pressure The normal working pressure within the distribution system should be approximately 75 psi and not

less than 35 psi. A minimum residual pressure of 20 psi shall be maintained at ground level at all

points in the distribution system. Higher pressures may be required at commercial, industrial, or

high-density residential areas.

7.5 Water System Design Calculations The Design Engineer must clearly state in the Design Criteria report, all design flows and pressure

conditions. The design calculations submitted to the City shall include:

The population used in the design

Annual Average daily flow (AADF)

Peak daily flow (PDF)

Peak hourly flow (PHF)

Peaking factors

Fire flow

Pipe size

Velocity, and

Minimum residual pressure

The City may provide a connection pressure at a set point along the existing system near the proposed

development. All hydraulic calculations shall be based on the connection pressure provided by the

City. When such information is not readily available, the Design Engineer shall rely on field data or

shall back calculate this information based on available information and accepted engineering

standards. Such data sources or assumptions shall be clearly stated in the design calculations. Head

losses through meters and backflow devices shall also be included in the calculations.

When available, the City may provide modeling support to review the design (in terms of flows and

pressures). Model computations, if performed by the Design Engineer, shall clearly be presented in a

tabular format showing system pressure, demand nodes and other pertinent information on plot(s)

that are legible. All important nodes shall be annotated to identify water demand. Both peak hour and

peak daily plus fire flow scenarios must be presented.


7-3

7.6 Water Main and Extension Location See Figure 2-1 in Section 2 for a guidance schematic.

7.6.1 Residential (service) Water Line Locate water lines for residential services minimum of five (5) feet away from existing or proposed

utilities, mailboxes, and other permanent structures. Service lines shall be straight connections from

water mains and shall not be encased in concrete. Service lines shall not be located beneath private

driveways or walkways. Water meters shall be located at the property line, in the utility servitude,

close to the right-of-way to allow for easy access. Water meters shall not be located beneath or

enclosed in fences, walls or decorative structures.

7.6.2 Normal Water Main Location Water mains shall be located on the North (streets oriented East-West) or West (streets oriented

North-South) side of the street. Water mains shall be located in the public right-of-way, at the center of

a 20 feet wide (minimum) water servitude. Minimize servitude overlap on private property.

Dedicated servitudes on private property shall be considered only when there are limitations in

locating the water main in the public right-of-way, submit written documentation for City review and

approval. Limit water main deflection to 50% of the manufacturer’s recommendations. Water lines

shall be extended to the furthest property line to accommodate future expansion and development.

7.7 Water Main Separation Requirements 7.7.1 Horizontal Separation from Sanitary Sewer Mains Water mains shall be laid horizontally, a minimum of 10 feet, from any point of existing or proposed

sewer. The minimum distance shall be measured edge to edge. Water mains and sanitary sewer shall

not be installed in the same trench.

Where water mains and sewers follow the same roadway, they shall be installed on opposite sides of

the roadway.

7.7.2 Vertical Separation A minimum of 18-inch vertical clear separation between water mains and sanitary sewers is required.

This distance should be measured from the outside diameters of the pipes. At all crossings, the water

main shall be encased in concrete. When local conditions prevent a minimum vertical clearance

between crossing pipes then sewer line shall be constructed of ductile iron pipe conforming to ASTM

A536 or ANSI/AWWA C151/A21.51. for a minimum distance of ten (10) feet in each direction from

the crossing with the sewer pipe joints arranged as far as possible from the water main joints. The

Design Engineer shall also obtain a variance permit from the DHH.

7.7.3 Separation from Storm Drains and Other Utilities Water mains shall maintain a minimum of six (6) feet horizontal separation from storm drains and

culvert and other utility lines. The water main shall maintain a minimum of two (2) feet vertical

separation from storm drains, culverts, and other utility lines. Water mains crossing less than two (2)

feet (upon DHH approval) below a storm drain or culvert shall require additional protection such as

the use of ductile iron pipe and pipe casing.


7-4

7.7.4 Separation from Sewer Manholes No water pipe shall pass through or come in contact with any part of a sewer manhole. Water mains

shall be located at least 10 feet from sewer manholes.

7.8 Water Main Diameters Only, 8, 10, 12, 16, 20, 24, 36, 42 and 48-inch diameter water mains shall be permitted. Pipe materials

for water mains and extensions shall be PVC or DIP depending on the location, use, size and approval

by the City. The Engineer shall submit in written justification, for the City’s review and approval, to

use other piping material. Such pipe material shall be sized to match the internal diameter of the

required PVC or DIP pipe.

7.9 Water Main Looping and Deadends To provide increased service reliability and to reduce head loss, dead ends shall be minimized by

making appropriate tie-ins whenever practical. Water mains shall be looped, if possible, to avoid dead

ends. In cul-de-sacs the water main shall be curved along the cul-de-sac/right-of-way, and the dead

end shall be located at the end of the curve.

All mains with dead ends shall be equipped with a fire hydrant 10 feet away from dead end (see Figure

7-1 below). Dead end lines for future expansion will require a master development plan to verify and

support sizing of the water main.

Figure 7-1 Cul-De-Sac Dead Ends

Notes:

1) This drawing is normally for streets oriented East-West. Flip drawing 90 degrees counter-clockwise for streets oriented North-South.


7-5

2) Water mains shall be located in public Right-Of-Ways. 3) Locate a fire hydrant 10 feet away from the dead end.

7.10 Potable Water Valves A sufficient number of valves shall be provided on water distribution and transmission mains to

minimize inconvenience and sanitary hazards during repairs. Valves shall be located at not more than

500 feet intervals in commercial, industrial, and business areas, and at not more than 800 feet

intervals in all other areas. Appropriate valving shall also be provided at all areas where water mains

intersect in order to provide effective isolation of water lines for repair, maintenance, or future

extension.

Valves shall not be installed in pavement unless specifically approved by the City. Valves shall also be

installed at all fire hydrant locations for ease of locating. Refer to Section 9 of this document for more

details.

7.11 Water Main Cover Use a minimum cover of five (5) feet over the top of the pipe for all water mains.

7.12 Surface Water Crossings for Water Mains Surface water crossings are to be avoided if possible. Consult City regarding surface water crossings

before final plans are prepared.

7.12.1 Above Grade All above grade water crossing pipelines must be adequately supported on an acceptable

foundation/support. Piping shall be ductile iron. Plans must be signed and sealed by an engineer

registered in the state of Louisiana. The installation must be protected from damage and must be

accessible for repair or replacement. Valves shall be placed at both ends of the water crossing at the

normal main depth, so that section of main can be isolated. A combination air release/vacuum valve

and crossing guards shall be provided. All above grade ductile iron piping shall be painted. Aerial pipe

crossings are further discussed in Section 12 of this manual.

7.12.2 Below Grade A minimum of five (5) feet shall be maintained from the top of water main to the design bottom

elevation of the open canal/ditch for below ground piping.

Sub-aqueous pipe crossings shall be horizontal directionally drilled using HDPE or fused PVC

pipe. In cases where the crossing is greater than 1,000 feet, a steel casing will be provided. For

water courses greater than fifteen feet in width, the water main shall be designed with flexible,

restrained or welded watertight joints.

Valves shall be provided at both ends of water crossings so that the section can be isolated for

testing or repair. The valves shall be easily accessible, and not subject to flooding. Additional

details pertaining to stream crossings can be found in Section 13 of this manual.


7-6

7.13 Roadway Crossings for Water Mains All water mains crossing major City roadways shall be bore and jacked or horizontally drilled. Open

trench installation is feasible at low traffic locations, the City shall be consulted prior to selecting the

method of crossing.

7.14 Air Release Valves and Blow offs for Water Mains 7.14.1 Air Valves Air valves shall be installed at high points along the water main to purge air from the line continuously

and to prevent vacuum formation during water main draining. The crown of the air valve vent shall be

located a minimum 6 inches above the base flood elevation. Further information regarding these

valves can be found in Section 9.2 of this manual.

7.14.2 Blow offs Blow off assemblies (or flush valves) shall be installed at low points of the water main to allow

periodic flushing of the mains. Where possible, fire hydrants shall be utilized in place of blow offs.

Blow off assemblies shall be located as close as possible to drainage ditches to prevent erosion and

ponding of water along roadways or streets. Automatic flush valves shall be used where requested by

the City.

7.15 Disinfection Requirements New, cleaned, and repaired water mains shall be disinfected as outlined in the City’s Standard

Specifications.

7.16 Existing Water Mains All existing mains shall be relocated, and installed as new mains if the existing mains are in the right-

of-way that fall under pavement.

Split casings can be utilized for existing mains that fall under new pavement that are perpendicular to

the main.

All main relocations shall be implemented with none or minimal interruption of service. Construction

that requires interruption of service shall be planned and scheduled at low peak demand hours or as

found acceptable by the City.

7.17 Thrust Restraints Refer to Section 4.5 of this manual.

7.18 Water Main Servitudes for Construction and Maintenance The Water and Sewerage Department requires safe and rapid access to all City water mains at all

times to repair main breaks, install taps, and perform preventive maintenance. For this reason, the

City‘s water mains shall be constructed within the street right-of-ways.Backlot or sidelot servitudes

will not be allowed.


7-7

7.18.1 Servitude All water pipelines shall be constructed in public rights-of-way, wherever feasible or in public water

main servitudes, when conditions dictate. If it is determined that infrastructure improvements must

be performed outside of existing right-of-way or existing servitudes, then it is necessary to obtain the

City’s approval for a new servitude, and the process must be started as soon as an approved pipeline

alignment has been decided upon in order to avoid delay in construction plan approval.

7.19 Service Connections 7.19.1 Service Connection Materials and Sizes Copper tubing shall be used for all water service lines three quarters of an inch (3/4") through two

inches (2”) in diameter. Material requirements for water service lines larger than two inches (2”) in

diameter shall be approved PVC or ductile iron pipe. Buried service connection pipe shall be designed

for a minimum pressure class of 250.

The service connection shall be as per the City’s Standard Specification Sections 209 and 3200.

7.20 Fire Code All systems requiring fire protection shall be designed such that fire flows and facilities are in

accordance with the requirements of Chapter 30 – Fire Prevention and Protection, Article III, Fire

Prevention Standards of the City of Shreveport Code of Ordinances.

7.21 Plumbing Code Water service and plumbing shall conform to the Chapter 22 – Buildings and Building Regulations of

the City of Shreveport Code of Ordinances and Louisiana State Plumbing Code(Part XIV (Plumbing) of

the State Sanitary Code).


7-8


8-1

Section 8

Fire Hydrants

8.1 General Location and Design Requirements Locate fire hydrants to facilitate quick access and use by the Fire Department. The Design Engineer

shall use engineering judgment, and common sense to locate the fire hydrant(s) such that it is in a

visible, and predictable location based on the type of development, with unobstructed accessibility to

meet the Fire Department’s needs . Minor variances in the locations or spacing of individual hydrants

may be approved, provided the functional intent of these design standards is achieved. The Design

Engineer should:

Provide fire hydrants at each street intersection and at intermediate points between

intersections as recommended by the fire chief.

Locate fire hydrants where they are readily visible by fire engines traveling along the street or

approaching on intersecting streets. Never obscure or obstruct hydrants behind fences, gates,

walls or landscaping.

Specify fire hydrant top colors in accordance with National Fire Protection Association’s

(NFPA) guidelines, as stated in NFPA 291.

Provide fire hydrants at street intersections and at the main entrance into a subdivision,

apartment complex or commercial development. Additional hydrants must be provided at a

spacing based on maximum spacing between hydrants. Spacing is measured along the route of

travel of a fire engine.

Provide fire hydrants at all dead ends in the water distribution system.

Locate fire hydrants such that, they are not placed within 3 feet of an above ground

obstruction and maintain 18 inches of clearance between the ground and the lowest hydrant

outlet cap. Hydrants shall be located within water servitudes providing at least 6 feet of

clearance on all sides of the hydrant, including protective bollards as directed.

Consider drainage arrangements/requirements during design of fire hydrants.

Size fire hydrants capable of a minimum flow of 600 gpm.

Specify a minimum of three, equally spaced, blue colored reflective strips, in the street or

paving adjacent to the fire hydrant for easy location at night.

Include a 6 inch operating valve (minimum).

Design/call out fire hydrants in accordance to City of Shreveport’s Standard Specifications.

Section 8 Fire Hydrants

8-2

8.2 Residential Subdivision Hydrant Location Standards Fire hydrant locations will be reviewed and approved as part of the subdivision approval process. The

Design Engineer should follow the General Location and Design Requirements as stated in Section 8.1

and:

Shall locate a fire hydrant at the intersection of each public and/or private street entrance into

the subdivision unless an existing fire hydrant meets spacing requirements.

Space additional fire hydrants 500 feet apart along all public and/or private streets within the

subdivision and along all perimeter streets.

For cul-de-sacs:

- Space fire hydrants 500 feet apart. As stated previously, a fire hydrant shall be located 10

feet away from dead ends.

8.3 Commercial and Multi-Family Hydrant Location Standards Fire hydrant locations will be reviewed and approved as part of the site plan/building permit approval

process. Provide a site plan showing all existing and proposed fire hydrant locations, all designated

fire lanes, and all Fire Department Connections (FDC’s) for building standpipe or sprinkler systems.

Whenever possible the Design Engineer shall locate hydrants with a setback of at least 40 feet from

the building.

Follow the General Location and Design Requirements as stated in Section 8.1 and:

First, determine whether new fire hydrants are required. New hydrants are not needed if existing

hydrants are close enough to provide the required coverage:

Within 500 feet of the most remote building corner or the most remote hazard on site,

measured as the hose lays along designated fire lanes or other clear access routes (within 500

feet of the most remote corner of fire sprinkled buildings)

Within 200 feet of all FDC’s for sprinkler and standpipe systems.

If existing fire hydrants do not provide the required coverage, new hydrants must be added as follows:

Locate a fire hydrant at the main entrance (driveway) into the development and at other

entrances identified as fire apparatus access roads (fire lanes).

Additional hydrants shall be spaced approximately 500 feet apart along all public roads and

along all designated fire lanes.

8.4 Private Fire Hydrants Private hydrants are those hydrants located on private property and/or connected to any water line

not owned and maintained by the City. In addition to compliance with NFPA 291, private fire hydrants

shall have their bonnets painted reflective white to identify them as privately owned and maintained.

The property owner is responsible for maintaining all private fire lines and fire hydrants in working

order at all times.


8-3

8.5 Maximum Fire Hydrant Spacing Table 8-1, lists the maximum spacing for fire hydrants for different land uses. Spacing distance shall be

measured along the centerline of the street or route, which the fire truck will most likely travel.

Table 8-1 Fire Hydrant Spacing

LAND USE SPACING REQUIREMENTS FIRE HYDRANT MAXIMUM SPACING (feet)

Single Family Residential 500

Two Story Townhouses and Apartments 300

Commercial and Industrial (including

Shopping Centers) 300

Off-site main extensions adjacent to undeveloped property

1000 or as required by the City of Shreveport

Cul-de-Sacs 500, to include hydrant within 10 feet of pipe end

8.6 Fire Hydrant Relocations Every attempt shall be made in the design phase of the projects to locate driveways outside of existing

fire hydrant locations. In the event that a hydrant must be relocated, the existing service line and valve

should be cut and removed from the existing water main and a new section of pipe installed with a

restrained flexible coupling. A new fire hydrant service line shall be installed perpendicular to the new

hydrant location.

In circumstances where the relocation of the existing hydrant would be 5 feet or less in either side-to-

side direction, the City will allow a 90 degree bend to be placed on the existing hydrant service line

and the hydrant to be relocated.


8-4


9-1

Section 9

Line Valves, Air Relief Valves and Blow-off Chambers

9.1 Line Valves Appropriate line valves shall be properly located within the distribution mains. Such valves include

gate valves, butterfly valves, air control/vacuum breaker valves, and check valves. Valves 24 inches in

diameter and larger shall be installed in a dedicated water tight manhole or vault. The following

guidelines will assist the Design Engineer in the placement of isolation valves.

Valves shall be provided at locations that will not unduly impact the customer or reduce fire

protection and be easy to locate.

A minimum of two valves shall be provided at tee fittings, except fire hydrant tees, which

require a valve on the hydrant branch only. Additional valves may be required and shall be

approved by the City.

A minimum of three valves shall be provided at cross fittings.

Valves shall not be installed at street gutters, roadside ditch slopes or ditch flow lines.

Valves shall be located on all hydrant leads from the water main.

Valves shall be located upstream and adjacent to all existing and proposed fire hydrants.

The number of dead end lines shall be minimized by looping mains. All dead end mains shall

include a fire hydrant, located 10 feet away from the dead end.

The maximum line valve spacing on distribution mains is given in Table 9-1

Table 9-1 Line Valve Spacing

Land Use Maximum Valve Spacing in Fee

Residential Areas 800 feet

Business, Commercial and Industrial Areas 500 feet

In case of sparsely populated residential or commercial areas, valve spacing shall not exceed one mile.

9.1.1 Isolation Valves The following three (3) types of isolation valves shall be considered for water mains:

Vertical Gate Valve

Horizontal Gate Valve

Butterfly Valve

While most valves can be direct buried, there may be instances when it may be preferable to

install valves inside valve vaults. The Design Engineer shall design valve vaults for such

Section 9 Line Valves, Air Relief Valves and Blow-off Chambers

9-2

instances, taking into consideration the workspace requirements of the City’s field operations

team for maintenance, dis-assembly, etc. The valve vault lids shall be removable.

9.1.2 Pressure Reducing Valves High incoming water pressure from water mains shall be reduced with pressure reducing valves

(PRV) when transitioning to lower pressure zones. When the maximum static pressures in a new

system exceeds 100 psi, pressure reducing devices shall be provided. Use only Lead free PRVs. PRVs

can be installed in series or parallel configuration. For residential and commercial purposes, PRVs

shall be installed downstream of water meters. The following parameters shall be used for the

selection of PRVs:

To avoid cavitation, the maximum differential pressure across the PRV should not exceed 50

percent.

The maximum velocity through the PRV should not exceed 15 fps, and the minimum velocity

shall not be less than 1.5 fps. These velocities are based on full pipe size. The design velocities

for regulation should range from 6 to 15 fps.

9.2 Air Valves A pressurized pipeline is never without air, and in certain cases the air volume can be substantial. The

sources of air in a pressurized pipeline are initial startup of pipelines when the pipe line is empty,

presence of dispersed air in water, and through operations of certain mechanical equipment, example

air entrainment on the pump suction lines. It is also crucial that air be permitted into the lines during

dewatering operations to prevent a line collapse due to formation of a vacuum. Air valves can both

release and permit air into the line thereby ensuring smooth pumping operations and preventing

water hammers or a line collapse. In general, combination air valves are preferred for water mains.

However, other valve types listed in Section 9.2.2 may be suitable in certain instances. The Design

Engineer shall select the appropriate valve after evaluating the hydraulics of the watermain. The

Design Engineer shall provide the City all relevant justification when valves other than combination

air valves are used.

9.2.1 Requirements Air release valves/(combination) air valves are required at high points, or significant changes in

grade, and about every 2500 feet horizontal runs.

9.2.2 Types Three basic types of air valves in accordance with AWWA C512:

Air Release Valves: Designed to collect and release air that accumulates in the valve. An air

release valve can be used to vent air that is accumulated at high points of a pipe line when the

piping is under pressure.

Air/Vacuum Valves: Designed to allow air to escape while the pipeline is being filled or admit

air when the pipeline is being drained. When the internal pressure drops below atmospheric,

the valve opens, allowing in air to prevent the pipe from collapsing. However, after the line has

been filled, the pressure in the valve keeps the valve from opening even if air accumulates in the

valve. An Air/Vacuum valve can be installed downstream of pumps and at high points to

exhaust large volumes of air during pump startup and pipeline filling.


9-3

Combination Air Valves: This valve is a combination of air release valve and vacuum relief valve,

and is capable of releasing small amounts of accumulated air from the pipeline while under

pressure. Usually smaller valves include the required mechanism in a single body, on larger size

a dual body style installation is common. While single body valves are relatively cheaper, dual

body installations provide operational advantages due to the possibility of keeping the

Air/Vaccum valve in operation while the air release valve is under repair or maintenance.

9.2.3 Location and Sizing The appropriate valve type shall be determined by the Design Engineer in accordance with AWWA

Manual M51. Generally, the water line shall be designed and constructed to minimize localized high

points. Automatic air valves shall not be used in situations where flooding of the manhole or chamber

may occur.

9.3 Blow-off Chambers Chambers containing blow-offs or flush valves, and other appurtenances shall allow adequate room

for maintenance. The access opening must be suitable for removing valves and appurtenances. The

chamber shall be drained to atmosphere where it will not be subjected to flooding, or to an absorption

pit located above the seasonal groundwater table. Adequate venting shall be provided.

9.3.1 Requirements Blow-offs or flush valves shall be used where sediment blow-off is required. The blow-off chamber

shall be of materials and construction similar to manholes, except the top shall be a precast eccentric

dome section. Chambers containing blow-offs or other distribution system appurtenances shall not be

connected directly to any storm drain or sanitary sewer, nor shall blow-offs be connected directly to

any sewers.

9.3.2 Locations Blow-offs shall be located in City right-of-ways and close to drainage ditches. Blow-offs shall be

located at all low points of the transmission pipeline.

9.3.3 Sizing The minimum size of blow-offs shall be 4-inches. Blow-offs for other sizes shall be as stated below:

Size of Water Main Size of Blow-off

16-inch and below 4-inch

18 to 42-inch 6-inch

48-inch and above 8-inch


9-4


10-1

Section 10

Water Meters

10.1 General Requirements All water service connections shall be metered. The Design Engineer is responsible for location,

selection, and sizing of water meters in accordance with the criteria listed herein.

10.2 Definitions 10.2.1 Residential Meter Residential meters are generally used in conjunction with a domestic water service of single-family

homes. These meters typically range from ⅝-inch through 2-inch in size.

10.2.2 Non-Residential Meter Non-residential meters are generally used to serve commercial or industrial water demand. These

meters typically range from 1-inch to 10- inches in size as required by the customer’s water demand,

while meeting all applicable plumbing code.

10.2.3 Irrigation Meter An irrigation meter is commonly used in conjunction with an irrigation water service to measure the

water flowing to a property that primarily services the needs of a landscape. All irrigation meters

must have a backflow prevention device.

10.2.4 Master Meter A master meter is typically used to serve a cluster of residential or commercial developments on a

single lot.

10.2.5 Sub-Meter These are privately owned meters that can be used to encourage effective conservation and efficient

use of water by fairly allocating its cost among the ultimate users within a master metered apartment

unit, office building, or shopping center. The sub-meters are not read and billed by the City as they are

considered private meters.

10.2.6 Deduct Meter (Private Meter) A deduct meter is usually installed on a specific water process, inside of private property. Deduct

meters subtract the process flow from the metered water flow.

10.2.7 Temporary Meters (Fire Hydrant Meter) Temporary water meters are typically used by contractors when drawing water for construction from

fire hydrants. These meters are typically 3-inches in diameter with a 2.5-inch hose and require

backflow prevention devices.

Section 10 Water Meters

10-2

10.2.8 Wholesale Meter (Customer City Meter) A wholesale meter is generally used to serve a wholesale municipal customer who purchases water

for resale.

10.3 Design Data Water meters shall be designed based on the peak water demand and type of application as necessary.

All meters shall be adequately sized in order to avoid the following undesirable conditions:

Volume, pressure and maintenance problems due to under sizing

Unregistered water use in low flow conditions due to over sizing

Accordingly, all applicable water usage including domestic, irrigation, mechanical, and fire demand

shall be considered while sizing a water meter.

10.3.1 Domestic Water Demand In the absence of an actual demand profile, the following modified fixture count method can be used to

estimate peak flow demand while meeting all applicable plumbing and fire codes.

10.3.1.1 Combined Fixture Value

Recommended fixture value as shown in Table 10-1 can be used to estimate combined fixture value as

necessary.

Table 10-1 Recommended Fixture Value

Fixture Fixture value @ 60 psi

Bathtub 8

Bedpan Washers 10

Bidet 2

Dental Unit 2

Drinking Fountain(public) 2

Faucet (kitchen sink) 2.2

Faucet (lavatory) 1.5

Faucet (utility sink) 4

Shower Head (shower only) 2.5

Toilet Flush Valve 35

Toilet Tank Type 4

Urinal (flush valve) 35

Urinal (wall or stall) 16

Urinal Trough (2 ft. unit) 2

Dishwasher 2

Clothes Washer 6

Hose (50 ft. length wash down)

1/2" connection

5/8" connection

3/4" connection

5

9

12

Source: AWWA M22: Sizing Water Service Lines and Meters, Second Edition


10-3

10.3.1.2 Peak Domestic Demand

Figure 10-1 and Figure 10-2 can be used to determine low and high range of peak demands using

estimated combined fixture value:

Figure 10-1 Water Flow Demand per Fixture Value – Low Range Source: AWWA M22: Sizing Water Service Lines and Meters, Second Edition

Figure 10-2 Water Flow Demand per Fixture Value – High Range Source: AWWA M22: Sizing Water Service Lines and Meters, Second Edition


10-4

10.3.1.3 Pressure Adjustment

Estimated peak demand shall be adjusted based on the actual available pressure at proposed meter

location (Table 10-2). Typically a fire hydrant test is requested to determine or verify the actual water

pressure at the peak demand of the proposed meter location.

Table 10-2 Pressure Adjustment Factors

Working Pressure a Meter

Discharge (psi)

Pressure Adjustment

factor

35 0.74

40 0.80

50 0.90

60 1.00

70 1.09

80 1.17

90 1.25

100 1.34


Example: The total fixture count of a facility at assumed 60 psi is calculated to be 100. The modified

fixture count at actual 80 psi will be 100*1.17= 117.

10.3.2 Irrigation Water Demand Irrigation water demand shall be estimated considering the following items:

Area to be irrigated.

Type of irrigation system to be used (spray or rotary).

Number of hose bibs and Pressure adjustment.

10.3.3 Mechanical Demand Mechanical water demand shall typically be obtained from Mechanical Electrical and Plumbing (MEP)

engineers considering the following items:

Type of equipment to be used (cooling towers, AC or wash down systems).

Type of usage (continuous or intermittent).

10.3.4 Fire Demand Fire demand shall meet the requirements of International Building Code (IBC), International Fire Code

(IFC) and National Fire Protection Agency (NFPA) and other regulations as applicable. Most recent

version of these regulations shall be used when determining fire demand. Fire demand shall typically

be obtained from Mechanical, Electrical and Plumbing Services (MEP), Fire Marshal’s office or the ISO,

and shall consider the following items:

Type of Building or Construction (Type 1A, 1B, IIA, IIB, IV, IIIA, IIIB, VA, VB).

Type of Occupancy (Residential or Non-Residential).

Type of Sprinkler System (Wet Pipe, Dry Pipe, Pre-Action and Deluge System), if any


10-5

Types of Fire Pump (if any).

10.4 Meter Classification 10.4.1 Positive Displacement (PD) Meter Positive displacement meters shall typically be used for low flow rates (<160 gpm) with a wide range

of flow fluctuations.

10.4.2 Non-Displacement Meter If large capacity is of primary importance, and the flows are usually above 10 or 15 percent of the

maximum rating and low flow accuracy is secondary, a Non-Displacement meter can be considered.

10.4.3 Compound Meter Compound meters consist of integrally connected positive displacement and non-displacement meters

and are used to measure both low and high flows. Low flows are measured through positive

displacement, while high flows are measured by the non-displacement meter. If close accuracy at low

flows is important but large capacity is also needed, a compound meter can used.

10.4.4 General Use Recommendations General recommended uses of various types of meters are summarized in the Table 10-3.

Table 10-3 Recommended Use of Various Water Meters General Category

General Category Sub-Category Typical Use

Positive Displacement (PD)

(Low Flow Application)

Nutating Disc Oscillating Piston

- Single Family Residential - Apartment Building with Less than 100 Units - Small Businesses - Schools and Other Public Buildings without Large Irrigation

Non- Displacement

(High Flow Application where

Accuracy is secondary)

Velocity Turbine Multijet Magnetic (Mag) Ultrasonic Propeller Proportional

- Large Hotels - Factories - Public Irrigation - Large Office Buildings - Pump Discharge - Hospitals

Differential Pressure Fixed Opening: Variable Differential Orifice Venturi Variable Opening: Fixed Differential Rotameter

- Pump Discharge - Wholesale Water Purchasers - Research Applications - Subsystem Metering

Mass Flow

Level Measurement

Weir

Parshall Flume

Compound Standard Compound Fire Service - Schools with Irrigation - Laundries - Large Apartment Buildings - Fire Lines & Hospitals



10-6

10.5 Meter Service Based on the estimated flow rate and type of service, the Design Engineer shall determine the need for

single or multiple services while considering the following criteria:

10.5.1 Domestic Service Meters A domestic service single meter shall be used primarily to measure domestic flows. Typical sizes of

small domestic meters are 5/8” , ¾”, 1”, 1-1/2” and 2”. A Domestic meter can also be used to

measure irrigation supplies and/or residential fire demand with approved fire sprinkler systems.

Domestic service meters are usually Nutating disc PD meters.

10.5.2 Large Domestic Service Meters Typical sizes of large domestic meters are 3”, 4”, 6”, 8” and 10”. These meters can be Nutating disc PD,

turbine or compound meters.

10.5.3 Fire Service Detector Check Device Detector Checks (DC) are typically installed on closed fire lines to measure fire flow to approved

automatic fire sprinklers. Minimum size of DC shall be 4”. Where necessary 6”, 8” and 10” DCs can be

used. Usually a 5/8”- 1” Nutating Disc PD meter is also installed in the bypass line. The bypass line

installed on a dedicated fire line shall not be used for domestic consumption.

10.5.4 Irrigation Service Meter Irrigation service meters are used to measure water used for irrigation or landscaping. Typical single

irrigation meter sizes are 1”, 1 ½”, 2”, 3”, 4” and 6”. All irrigation service lines shall also include a

backflow prevention device.

10.5.5 Combined Water and Fire Services Meters A single or combination of meter(s) can be used to measure combined water, fire and/or irrigation

flows as required.

10.5.5.1 Small Combined Water and Fire Service Meter(s)

Typical size of meter to measure small combined water, and internal fire sprinkler flow is 1”-2”. A

Multijet turbine meter shall be used to measure residential/domestic service with fire demand.

10.5.5.2 Large Combined Water and Fire Service Meter(s)

Typical size of fire meters used on combined service shall be 4” (min.), 6”, 8” and 10”. Typical size of

domestic meter on combined service is 1”, 1-1/2”, 2”, 3”, 4”, and 6”.

10.6 Location and Installation Water meters shall typically be located at the property line (preferably at the center of the sidewalk)

in the public right-of-way or in a servitude dedicated to the City.

10.6.1 Accessibility All meters must be placed in a location where they can be read and accessed by the City’s meter

reading personnel. The meter must be accessible at all times and the surrounding area must be kept

clear of vegetation and other obstructions.


10-7

10.6.2 Minimum Length of Unobstructed Pipe The meter shall be located in a straight, clean pipe of uniform, circular cross section, without any

fittings or obstructions. A minimum length of ten (10) diameters of straight, rigid pipe must be fitted

on the intake side of the meter, and a minimum of five (5) diameters of straight rigid pipe on the

discharge of the meter to minimize flow disturbance. Where this requirement cannot be met, it may be

acceptable (upon approval from the City) for the meter to be installed with a minimum of five (5)

diameters of straight, rigid pipe upstream of the meter, and a minimum of two (2) diameters of

straight, rigid pipe immediately downstream. However, this will only be considered in those

circumstances where the meter manufacturer warrants that the meter will operate to the required

accuracy under the revised conditions. Minimum length of straight, uninterrupted pipe is summarized

in Table 10-4.

Table 10-4 Required Minimum Straight Unobstructed Pipe Length for Water Meter

Meter Size (in)

Min. Straight Unobstructed Length

Intake or Up Stream (U/S) Side (ft.) Discharge or Down Stream(D/S) Side (ft.)

5/8 0.52 0.26

¾ 0.63 0.31

1 0.083 0.42

1-1/2 1.25 0.63

2 1.67 0.83

3 2.5 1.25

4 3.33 1.67

6 5 2.5

8 6.67 3.33

10 8.33 4.17

12 10 5

>12 As Calculated As Calculated

10.6.3 Miscellaneous Items The meter shall be installed so that there is a full pipe of water on both the intake and discharge sides

of the meter at all flow rates. The meter shall not be installed in a section of pipe with potential for air

pockets or that does not run full of water. If it is likely that air will become entrapped near the meter,

an air valve shall be installed. Filtering equipment shall be installed on the intake side of the meter.

Where the meter has to be fitted to plastic or polyethylene pipelines, it must be supported by a

concrete thrust block or fabricated steel bracing to maintain stability.

10.7 Meter Box and Vault 10.7.1 General No meter shall be installed deeper than 4.5 feet below ground level. Where a meter is installed

underground, sufficient space must be provided to facilitate easy access for maintenance and reading

at all times.


10-8

10.7.2 Meter Box All 2” or smaller meters located down to 1.5’ below ground will require a suitable meter box to house

the meter. All meter boxes are to be constructed of plastic with cast iron or Advance Metering

Infrastructure (AMI)-compatible Radio Frequency (RF) lids as approved by the City.

10.7.3 Meter Vault All 3” or larger domestic, fire, irrigation or combined meters will require a meter vault. For meters

located between 1.5 feet and 4.5 feet below ground, an access pit or meter vault will be required.

10.8 Special Design Considerations 10.8.1 Deduct Meter 10.8.1.1 General

Deduct meters can be considered for facilities where the water either evaporates or is consumed in a

specific process including, but not limited to, cooling towers, bottling plants or similar applications as

approved by the City.

10.8.1.2 Typical Configurations

The following are the most common configurations currently approved for use by the City. Other

configurations may be submitted,for review on an individual basis.

Wastewater Meter: Wastewater meter to measure total discharge into the wastewater

collection system. If the customer has more than one wastewater lateral, a meter will be

required for each lateral.

Deduct Water Meter: Deduct water meter(s) can be used to measure water which does not

return to the wastewater collection system. Volume measured on the deduct meter is

subtracted from the total water volume for the calculation of wastewater charges. Deduct

meters are typically located at both the supply side, and the return side of the process as

approved by the City. An example would include water to be consumed in a manufacturing

process.

10.8.2 Wholesale Meter 10.8.2.1 General

Wholesale customer meters are coordinated through the City. Wholesale customer meters are

typically designed and constructed by the party requesting the service from the City. The City reads

and maintains wholesale meters.

10.8.2.2 Typical Configurations

A wholesale customer meter assembly typically consists of a primary and a secondary flow meter. The

Primary flow meter shall be sized based on the estimated flow to the customer. Venturi tubes or

similar meters, as approved by the City, shall be used as primary flow meter. The Design Engineer

shall also size a secondary flow meter to measure any flows through the bypass line.

11-1

Section 11

Cross Connection Protection

A cross connection is a direct or indirect connection of a non-potable water line with a potable water

supply line. Cross connections can significantly deteriorate the quality of potable water, and could

render it a health hazard. The degree of hazard posed by cross connections depends upon the type of

potential contaminant and the likelihood for backflow to occur.

HIGH HAZARD is a cross connection involving any substance that if introduced into the public water

supply could cause death, illness, spread disease or has a high probability of causing such effects.

LOW HAZARD is a cross connection involving any pollutant that is not generally a health hazard, but

would pose a hazard if introduced into the potable water supply, constitute a nuisance or be

aesthetically objectionable.

11.1 Required Pipeline Separation The required pipeline separation shall be as given in Section 7.7.

11.2 Backflow Prevention Devices Backflow is an undesirable reversal of flow of liquid from a non-potable system to the potable water

distribution main piping system. The causes of backflow are backpressure, back-siphonage, or a

combination of the two. The backflow devices used to prevent backflow from a potential cross

connection include:

Air gaps

Atmospheric vacuum breakers

Pressure vacuum breakers

Double check valve assemblies

Reduced pressure zone backflow prevention assemblies

Barometric loop

In all cases, the Design Engineer shall be responsible for selecting the appropriate backflow

prevention devices for a specific location. In parallel installations, backflow devices should be the

same type (provide the same level of protection), and should have the same size and flow capacity.

11.3 Backflow Prevention for Commercial, Industrial, and Multi Family Residences All commercial, industrial, and multi-family residential projects shall install a reduced pressure

principle backflow preventer assembly or a double check valve assembly. The device shall be installed

above ground in an enclosure (below ground installation in valve vaults will not be permitted), the

Section 11 Cross Connection Protection

11-2

piping and device shall be insulated to provide freeze protection. Design Engineer shall add the

backflow prevention device(s’) size information and coordinates. Projects with fire sprinklers and

standpipe systems, and projects with on-site fire protection systems will be required to install a

reduced pressure type backflow preventer with a leak detector assembly.

11.4 Backflow Prevention for Irrigation System A reduced pressure principle backflow preventer shall be required on all irrigation systems that have

chemical substances or additives. In cases where an irrigation system does not have chemical

substances or additives, a double check valve backflow (DCVA) prevention assembly shall be required.

11.5 Locations for Backflow Prevention Devices 11.5.1 Locations Cross connection can occur at several locations within commercial buildings, hospitals, farms, houses

and apartment complexes. Backflow prevention devices are required at all cross connections. Follow

plumbing code requirements for toilets, urinals, hose connections, air conditioning units, heat

exchangers and other water cooled equipment. The ensuing subsections present examples of locations

for backflow prevention devices.

11.5.1.1 Fire Sprinkler Systems

Fire sprinkler systems can be a source of potable water contamination. During a fire emergency, non-

potable water can be drawn into the City’s potable water system because of the pressure and volume

demands. Fire sprinkler systems with no chemicals added shall be isolated from the potable water

supply by double check valve assemblies. Fire sprinkler systems which contain additives or are cross

connected with other piping systems shall be isolated from the potable water supply by reduced

pressure zone backflow prevention assemblies.

11.5.1.2 Irrigation / Lawn Sprinkler Systems

Irrigation systems are a high hazard since in nearly all instances chemicals are applied. Backflow

preventer such as reduced pressure zone backflow prevention assemblies or approved vacuum

breaker shall be located on all sprinkler systems.

11.5.1.3 Auxiliary Sources

There shall be no connection between the distribution system and any pipe, pumps, hydrants, or tanks

whereby unsafe water or other contaminats may be discharged or drawn into the public potable water

system.

11.5.1.4 Wastewater Treatment Plants, Pump Stations and Water Reduction Facilities

Common cross connections in plants of this type are usually found between the potable water system

and:

Water operated sewage sump ejectors; high hazard.

Chlorinators using potable water when disinfecting wastewater; high hazard.

Sewer lines for purpose of disposing of filter or softener backwash water or water from cooling

systems; high hazard.

Reduced Pressure Backflow Prevention Devices should be used in these locations.


11-3

11.5.1.5 Water Treatment Plants

Common cross connection hazards in plants of this kind are found between the potable water system

and:

Raw water pumps for priming, cleaning, flushing or unclogging purposes.

Any chemical feed applications using potable water system.

Filter backwash systems.

Chemical Feed Day Tank Fill Stations.


11.5.1.6 Plating and Chemical Companies

The cross connection hazards found in plants of this type include cross connections between the

public water supply and:

Plating facilities involving the use of highly toxic cyanides, heavy metals in solution, acids and

caustic solutions.

Plating solution filtering equipment with pumps and circulating lines.

Tanks, vats or other vessels used in painting, descaling, anodizing, cleaning, stripping, oxidizing,

etc. for the preparation or finishing of products.

Steam generating facilities and lines which may be contaminated with boiler additive chemicals.

Water cooled equipment which may be connected to a sewer such as compressors, heat

exchangers, and air conditioning equipment.


11.5.1.7 Other Locations

Other similar areas include hospitals, convalescent and nursing homes, funeral homes and mortuaries,

schools and universities, medical laboratories, car wash facilities, laundries, potable water tanks,

swimming pools, green houses, and tank trucks and sprayers. In circumstances where the Design

Engineer encounters these areas, the Design Engineer shall determine specific locations for backflow

prevention devices.

11.6 Plumbing Code In all circumstances, the installation of backflow prevention devices shall conform Chapter 22 –

Buildings and Building Regulations of the City of Shreveport Code of Ordinances, requirements of the

City’s Permitting Office standards, and Louisiana State Plumbing Code (Part XIV (Plumbing) of the

State Sanitary Code).


11-4


12-1

Section 12

Pipe Aerial Crossings

12.1 General Considerations With the approval of the City, the Design Engineer shall either use piers or supports/carriage for pipe

aerial crossings. If permitted, an existing bridge structures may be used to cross streams and ditches.

Before designing the crossing, the Design Engineer shall contact the owner of the bridge structure and

obtain written approval to determine if its use is permissible.

The design elevation of the proposed aerial crossing line shall be maximum of:

The elevation of the lowest chord of the nearest adjacent bridge or

Shall be above the 100-year Floodplain Elevation

12.2 Design Considerations The Design engineer shall incorporate the following design considerations:

Pipes used for aerial crossings that span the length of elevated pier crossings shall be flanged

ductile iron pipe, Pressure Class 350 conforming to AWWA C115, C150 & C151.

All pipes over piers spaced greater than normal pipe lengths of 18 feet or 20 feet shall be

multiple length pipes with flanged joints and gaskets suitable to convey the fluid at ambient

conditions.

The pipes shall be designed per AWWA C150 to limit stresses.

Pipe deflection (at center of span) when flowing full shall not exceed 0.15 percent of the pipe

length.

Expansion joints and pipe rollers shall be provided as required.

Adequate provisions must be made for thrust restraints at points of transition from a buried

pipe to an exposed pipe and vice versa.

Wastewater mains shall be fully restrained across the aerial section.

The impact of increased load due to the proposed crossing shall be calculated before finalizing

the aerial crossing option.

Adequate access shall be provided to both ends of the crossing.

The provisions for corrosion control shall be incorporated, including coating systems.

Freeze potential shall be considered for low flow aerial crossings.

Section 12 Pipe Aerial Crossings

12-2

Install isolation valves or other flow regulating devices as required. The flow regulating devices

shall be located on each bank or at a safe distance from each bank. There shall be no discharge

into the stream or the water body.

Install supports for all joints in pipes utilized for aerial crossings to prevent overturning and

differential settlement. Expansion joints or couplings shall be used, as required, at locations

where the aerial pipe connects to buried piping.

Air relief provisions (with freeze protection) shall be considered at the high points.

Supports, piers or abutments shall be designed to withstand the hydrodynamic effect of the

stream flow pressure on the pipes and its supports.

All exposed pipes shall be epoxy coated (externally).

All flanges, nuts, bolts shall conform to AWWA standards.

The nuts and bolts shall be stainless steel or as directed by the City.

The Design Engineer shall submit detailed calculations for loading bearing, anchor design, and other

engineering calculations to the City for review.

13-1

Section 13

Pipe Stream Crossings

13.1 Design Considerations The Design Engineer shall consider the following in selecting stream crossing locations:

Avoid locations with severe channel instability problems.

In locations with meandering channel bends, the crossing should be placed halfway between

the two adjacent bends or upstream of the meandering bend.

Avoid locations where there is an abrupt drop in the channel bed, flow depth or localized scour

holes. These locations indicate potential channel bed instability.

In locations where flow constrictions occur, the crossing should be placed upstream of flow

constriction.

Avoid placement near sediment traps and storm water control ponds. The crossing should be

located downstream of these structures.

Stream crossing shall be located such that the pipe will be protected from impacts of

construction of other utilities or structures.

As far as possible, inverted siphons are to be avoided. Gravity sewers shall be sloped to

maintain self-cleaning velocities.

Provide a minimum cover of five (5’) feet over the pipe at stream crossings.

For crossings over 15-feet (measured at low flow conditions), the following shall be

implemented:

- Isolation valves shall be provided at both ends, within half a mile for mains less than 24

inches, and within 2.5 miles for mains 24 inches and larger. The valves shall be easily

accessible and not subject to flooding under normal conditions.

- All other mains, services, taps, hydrants, or other devices located inside of the limits of the

isolation valves shall also have easily accessible isolation valves.

- Permanent taps shall be provided to install a meter check for leakages and for sample

collection. It is permissible to have combination taps for both an air relief valve and a

pressure tap provided the assembly meets the above criteria and the air relief valve can be

isolated during the testing of the crossing.

The pipeline shall be checked for the potential for buoyancy lifts, and designed with

antifloatation devices.

Section 13 Pipe Stream Crossings

13-2

13.2 Material and Appurtenances The stream crossing shall be installed in a casing pipe under the ditch or stream. The

water/wastewater main shall be restrained ductile iron pipe. If a trenchless technology is used for

stream crossing, the Design Engineer shall select the appropriate pipe material. There shall be an

access manhole on each bank of the ditch or stream. The height of manhole shall be 3-feet above the

100 yr. flood elevation.

13.3 Erosion Control The Design Engineer shall incorporate erosion control in the design. The Design Engineer shall follow

the requirements of the regulatory agency or the Owner responsible for the ditch or stream. The

design shall follow all permit requirements of the regulatory agencies. The stream crossing shall be

covered with riprap if the velocity of the flowing water is anticipated to exceed ten (10) feet per

second. In areas where there is a planned channel improvement, coordinate with the Designer of the

channel improvement to determine any additional improvements that may be required. In addition,

the Design Engineer shall design the stream crossing to have a minimum depth of five (5) feet from

the top of the pipe to the bottom of the channel or as stipulated by regulatory agency in case of

navigable waters.

Appendix A-1

Appendix A

Consulting Rating Form

CITY OF SHREVEPORT

DEPT. OF ENGINEERING AND ENVIRONMENTAL SERVICES OFFICE OF THE CITY ENGINEER CONSULTANT RATING FORM

Project Name/No: Consultant:

Type of Construction: Coordinator:

Explanation: To evaluate the Consultant, circle the number which best rates their performance from the range for each of the five criteria. Rating will be

from worst to best on a 0.0 to 6.0 scale, and will be in accordance with the detailed attached rating factors.

1. Demonstration of knowledge of acceptable Design Criteria and procedures. Considerations include but not limited to demonstrated familiarity with Design Manuals, AASHTO specifications, good design practices and design standards.

0 1 2 3 4 5 6

Remarks:

2. Ability to meet contract requirements with minimum direction. Considerations include whether or not the Consultant was a self starter and whether or not the Coordinator spent considerable time instructing the consultant and/or correcting his work.

0 1 2 3 4 5 6 Remarks:

Appendix A Consulting Rating Form

Appendix A-2

CONSULTANT RATING FORM 3. Quality of plans. Consideration on the legibility, neatness, organization, format,

accuracy of quantities, details and correctness of plans. Quality of plans primarily based on reviews made at an advanced stage of preliminary and final design.

0 1 2 3 4 5 6 7

Remarks:

4. Completion of work within the terms of contract. Considerations include whether or not the Consultant completed the plans on or before the contract completion date; and whether or not intermediate deadlines were met. Any delays due to the City's inability to provide data or reviews in a timely manner should be considered in this rating and comments provided.

0 1 2 3 4 5 6

Remarks:

5. General spirit of cooperation. Excellent - very cooperative, very willing to follow instructions, interested in project. Unsatisfactory - argumentative, reluctant to follow instructions, indifferent to projects.

0 1 2 3 4 Remarks:


Appendix A-3

CONSULTANT RATING FORM

General Comments:

Rater’s Signature: Date:

Cons ultant’s Comments :

Consultant’s Signature: Date:

City Enginee r’s Comme nts :

City Engineer’s Signature: Date:

Dire c tor of Opera tional S ervic e s ’ Comments:

Director of Operational Services’ Signature: Date:


Appendix A-4

CONSULTANT RATING FACTORS

1. DEMONSTRATION OF KNOWLEDGE & DESIGN CRITERIA

6 No design errors on plans 5 Minor design error 4 Few minor design errors 3 One major and/or several minor errors 2 More than one major error 1 Lack of knowledge. Large number of questions 0 Totally unacceptable

2. ABILITY TO MEET CONTRACT REQUIREMENTS W/MINIMAL DIRECTION

6 No questions w/no errors 5 Few intelligent questions w/few errors 4 Few questions 3 Few less than intelligent questions 2 No questions w/numerous errors, numerous dumb questions, needs some

prodding to look at options. 1 Continuous questions on major & minor issues 0 No understanding

3. QUALITY OF PLANS

7 No errors 6 Few minor errors/neat plans 5 Some minor errors/neat plans 4 Some minor errors/plans are not neat. A major error/neat plans 3 Numerous minor errors/average plans 2 Major errors/lacking quantities 1 Numerous errors/fairly neat plans. Few errors/unorganized or minimal plans 0 Totally unacceptable

4. COMPLETION OF WORK WITHIN TERMS OF CONTRACT

6 All submittal early 5 All submittal early or on time 4 All submittal on time; some early, some slightly late 3 Slightly behind schedule with some submittal on time 2 Always slightly behind schedule 1 Late letters frequently sent 0 Non compliance


Appendix A-5

5. SPIRIT OF COOPERATION

4 Extremely/always cooperative 3 Mostly cooperative 2 Sometimes cooperative & sometimes questionable 1 Usually uncooperative or argumentative 0 Uncooperative/argumentative


Appendix A-6

This Page Intentionally Left Blank

Appendix B-1

Appendix B

Plan Review Checklist

PLAN REVIEW CHECKLIST

PURPOSE:

The purpose of this checklist is to expedite plan review of street, storm drainage, water, and sewer plans

requiring approval by the City Engineer, as well as help standardize plans for the City of Shreveport.

This checklist is intended to help reviewers and the consultants standardize plans and minimize the

probability of misinterpretation by field personnel during construction layout engineering and

inspection.

This checklist is intended to be a guide and reference for the submittal and review of design plans. The

items listed on the checklist are not to be intended as all-inclusive for every project. Depending on the

scope of the project, sheet requirements may or may not include all of the sheets as listed below, or may

include additional sheets not listed in this checklist.

INSTRUCTIONS:

1. The checklist is separated into the following sections to correspond to the general requirements of

the plan submittal.

A. Overall Drawing Requirements

B. General Sheets

C. Layout Sheets

D. Right-of-Way Sheet

E. Plan and Profile Sheet(s)

F. Standard and Special Detail Sheet(s)

G. Erosion Control Layout Sheet

2. Fill in the Project Name, City of Shreveport Project Number (if known), and submittal date, on the

first page of the checklist.

3. Complete each section of the checklist by checking each appropriate item as shown on the submitted

plans.

4. Where items or sections do not apply, insert a “N/A” (non-applicable) in the allotted space provided.

5. Submit completed checklist with plan submittal package.

Appendix B Plan Review Checklist

Appendix B-2

PLAN REVIEW CHECKLIST

PROJECT NAME:

DATE:

PROJECT NUMBER:

DESIGNER:

OVERALL DRAWING REQUIREMENTS

1. ______ Plan Sheet Size is 22" x 34"

2. ______ Plans are drawn to a Horizontal Scale of 1"=20', and a vertical scale of 1"=4'. (Larger scales can

be used for increased clarity or conciseness of the plans with prior permission of the City

Engineer. Smaller scales can be used in the profile for sewer mains).

3. ______ Each Sheet shall contain a sheet number, the total number of sheets in the plans, and the proper

project number.

4. ______ A revision block will be included on each sheet. Revised sheets submitted shall have identifying

notations and dates for each revision.

5. ______ All lettering shall be ≥0.125"

6. ______ The design engineer information including name and address is shown on each plan sheet.

7. ______ The final plans and specifications shall be signed, dated and sealed by the responsible

engineer(s). Responsible engineer shall be a registered Professional Engineer, licensed to

practice in the State of Louisiana.

8. ______ The final set of plans shall be submitted on full size, 20 lb. weight archive-able paper.

Specifications shall be printed on 8 ½" X 11" paper. All final sets (plans and specifications) shall

be clipped and bound.

9. ______ Once approved, the final set of plans and specifications shall also be submitted electronically to

the city. All reference files will be bound into one overall drawing file. The naming format for

the drawing files shall be “Project Number, Page #, _, Total Page# (i.e. 01C0011_20, project

number is 01C001, the page # is 1, and the total page # is 20). Final plans shall be submitted

either in Microstation or AutoCad. Final plans (signed, dated and stamped) shall also be

submitted in ‘pdf’ format. Final specifications shall be submitted in both ‘Microsoft Word’ and

‘pdf’ formats.


Appendix B-3

GENERAL SHEETS

General sheets shall include the Title Sheet, Index Sheet, General Notes, Legends and Abbreviation, Hydraulic

Profiles, and Pipe, Valve and Equipment Schedules. Project work involving upgrades to existing treatment

plants or new treatment plans shall include Process Flow Diagrams. Minimum requirements for each of these

sheets are listed below.

TITLE SHEET

The title sheet shall list the following information.

1. ______ All plans shall include this text at the top: “CITY OF SHREVEPORT, LOUISIANA. DEPARTMENT OF

ENGINEERING AND ENVIRONMENTAL SERVICES. OFFICE OF THE CITY ENGINEER.”

Immediately below this text, the name of the project or title, city, and parish shall be listed .

2. ______ Project number

3. ______ Location Map showing project location in relation to streets, railroads, and physical features.

The location map shall have a north arrow and appropriate scale. The location map shall show

the beginning and end stationing of the project.

4. ______ Vicinity Map showing project location in relation to City of Shreveport map. The vicinity map

shall have a north arrow and appropriate scale.

5. ______ For City of Shreveport projects, the Mayor, Director of Operational Services, or the Director of the

responsible department, and City of Shreveport City Council Members listed by district, shall be

shown on the title sheet.

6. ______ The name of the City’s Water and Sewer Director.

7. ______ Funding information for City of Shreveport projects.

8. ______ Approval block for signature by the City Engineer, and date.

9. ______ Approval block for signature by the Assistant City Engineer, and date.

INDEX SHEET

Index sheet(s) shall be included for all projects.

GENERAL NOTES

General notes shall include the following at a minimum:

1. ______ A note stating the following, in bold letters and framed in a box: “CONTRACTOR TO CALL LA.

ONE CALL OR THE UTILITY COMPANY”

2. ______ A note listing the agencies and their phone numbers in case of an emergency.

3. ______ A note stating that the Contractor shall be responsible for protection of existing utilities in the

area of work.

4. ______ A note stating that Health and Safety at the jobsite, during construction, shall be the Contractor’s

responsibility.


Appendix B-4

5. ______ A note identifying the permits that the Contractor will need to obtain prior to beginning work.

6. ______ A note pertaining to relevant coordinates, datum used in surveys, and adjustment factors (if

used).

7. ______ A note stating the following: “REDLINE DRAWINGS SHALL BE PRESENTED TO THE CITY’S

REPRESENTATIVE PRIOR TO PAY REQUEST APPROVAL AND FINAL COMPLETION.”

8. ______ If required, a note stating that the City’s standard specifications will be used for the project.

9. ______ If required, a note regarding demolition activities, directing the Contractor to contact the City

regarding preferences in salvaging demolished items.

10. ______ If required, a note pertaining to disposal of demolished items in compliance with prevailing

regulations.

LEGENDS & ABBREVIATIONS

All legends and abbreviations used in the plans shall be listed in these sheet(s). For smaller jobs, it may be

possible to merge this with the General Notes sheet. For complex projects, separate sheets for legends and

abbreviations may be required for each discipline.

HYDRAULIC PROFILES

Hydraulic profiles may not be required for all projects; they are required for certain treatment plant projects,

pump station and piping projects. Where required, such profiles shall be constructed for each structure,

piping junction as required. It shall be developed for current, design, and future flows.

PIPE, VALVE & EQUIPMENT SCHEDULES

These schedules may only be required for certain projects. The Design Engineer shall list these schedules for

pipes, valves and/or equipment of certain sizes. When used, the Design Engineer shall list their sizes

(diameters, dimensions), type (pipe type, pipe class/schedule, valve type, valve opening, equipment operation

type, etc.), capacity (flowrate, throughput, etc.), and electrical sizes (HP, rpm etc.).

LAYOUT SHEETS

Layout sheets shall include Site Layout sheets, and Topographic Survey sheets. Requirements for these sheets

are stated below.

SITE LAYOUT SHEETS

1. ______ North arrow and scale

2. ______ Name of subdivision and all street names and an accurate tie to at least one quarter section

corner. Unplatted tracts should also have an accurate tie to at least one quarter section corner.

3. ______ Boundary line for project area.

4. ______ Location and description of major waterways or water bodies within or adjacent to the project

area.


Appendix B-5

5. ______ Name of each utility within or adjacent to the project area and the telephone number of the

contact.

6. ______ If applicable to the project, Contractor staging area, and spoils area.

7. ______ If more than one general layout sheet is required, a match line should be used to show

continuation of coverage from one sheet to the next sheet.

TOPOGRAPHIC SURVEY

For most projects survey information can be included in the layout sheets. However, for projects involving

pipelines, relevant survey information shall be shown on all applicable plan and profile sheets.

1. ______ North arrow and scale.

2. ______ A legend is shown for all symbols and hatches used.

3. ______ Vertical Datum stated, and at least two benchmarks are shown and listed. The monument number, elevation, northing and easting, and location description shall be shown.

4. ______ Existing contours shown at each foot of elevation (unless other approved).

5. ______ Street names are shown along roadway centerline.

6. ______ Limits of right-of-way is shown on the plan.

7. ______ Call-outs for all objects and features on survey.

8. ______ Existing sewer and storm drainage structures are shown and listed and stationed with rim

elevation, pipe size, pipe material, and pipe invert elevation.

9. ______ Underground stormwater, sanitary sewer, and waterlines are shown and labeled with size and

material type.

10. ______ All utility structures such as electrical vaults, power poles, guy wires, gas meters, water meters,

water vaults, telephone poles, telephone vaults, are shown and called out with station and offset.

11. ______ All overhead and underground utility lines are shown and labeled.

12. ______ Utility servitudes are shown and labeled.

13. ______ Culverts are shown, and labeled with pipe material, pipe size, flow line elevation, and station and

offset at each end. Any extension of an existing culvert is shown and labeled.

14. ______ Landscape features such as trees, shrubs, and site amenities are shown and labeled with station

and offset.

15. ______ Property Lines are shown. Property including owner, address, lot number is shown.

16. ______ The survey information is shown for 300' beyond the project limit.

17. ______ All driveway locations are shown on the plan, stationed to the center of driveway. The width and

material type of driveway is listed.


Appendix B-6

18. ______ The sidewalks are shown on the plan. The type of material is called out on the plan. Any ramps

are shown.

19. ______ The survey is signed and stamped by a licensed surveyor in the State of Louisiana.

RIGHT-OF-WAY SHEETS

These sheets may be issued by themselves or attached to Design Reports and Specifications. Right-Of-Way

sheets shall include the following information:

1. ______ Parcel number.

2. ______ Lot number.

3. ______ Subdivision.

4. ______ Name of current owner.

5. ______ Servitude takings (Should be labeled as P-# for Right-of-way, D-# for drainage, T-# for

temporary construction) with dimensions.

6. ______ Right-of-way takings.

7. ______ Geographical Number.

8. ______ Plat sheets are to be 8 ½"x11".

PLAN AND PROFILE SHEETS

Plan and Profile sheets shall include Site Civil sheets, Architectural sheets, Structural sheets, Process

Mechanical sheets, Mechanical sheets, Electrical sheets and Instrumentation and Control sheets. The

requirements for these sheets may vary depending on the project scope. Not all of these sheets are discussed

in detail in this section. Overall requirements for these sheets are listed below.

SITE CIVIL PLANS

1. ______ North arrow and scale (Horizontal scale of 1"=20').

2. ______ Elevation and location of all applicable bench marks.

3. ______ Show Right-of-Way boundaries and limits and associated dimensions.

4. ______ Detailed locations of proposed structures, process units, piping, vaults, and other items.

5. ______ Existing structures such as manholes, sanitary sewer manholes that need to be adjusted are

shown on the plan. Sanitary sewer manholes need to state the flow line elevations, sewer main

size, and rim elevation.

6. ______ Show all existing and proposed utilities such as power, gas, oil, water, telephone, existing storm

sewers and existing and proposed sanitary sewers showing direction of flow and other such

items located in conformance with the best information available or by field surveys, and

identified as to size, type of utility, and where known- the type of material.

7. ______ Show all utility servitudes. Dimension and label width and ownership of servitude(s).


Appendix B-7

8. _____ All existing and known proposed improvements shall be identified as to type, size, material, etc.,

as may be applicable. Existing conditions need to be screened back (presented as a lighter line

color) on the drawing.

9. ______ Proposed work needs to be obviously darker on the drawings than the existing conditions.

10. ______ Show the flow line and top of bank of existing open channels and the centerline and top of bank

of proposed open channels.

11. ______ Show pipeline stationing along the centerline.

12. ______ Show complete centerline curve data for each curve along with points, bearings, curvature, and

tangency.

13. ______ Show all railway information if applicable; their ownership, right-of-way width, angle of

intersection and location.

14. ______ Show boring locations if available.

15. ______ Limits of clearing shall be shown on the plan. All encroachments or excess right- of-way is

clearly shown on the plan.

16. ______ Profile grade line identified on plan.

17. ______ The plans will show a 10' horizontal separation between the water and sewer lines.

18. ______ Include drainage plans for applicable concrete pad drawings.

19. ______ Callout pipe size, material and service type on plans (ex: 24-PVC-SFM for 24” PVC sewer force

main)

20. ______ Callout valve sizes, valve types and fittings (ex: 42-BFV for 42 inch Butterfly Valve)

21. ______ Identify the Control Points and Bench Marks. Callout Northings, and Eastings of all manholes,

pipe fittings, valves, corners of buildings, paving, roads, etc.

SITE CIVIL PROFILES

22. ______ The profile shall have a horizontal scale of 1"=20', and a vertical scale of 1"=4', unless approved

by the City Engineer.

23. ______ Existing and proposed grade elevations are shown.

24. ______ Depth and location of existing or proposed utilities and sanitary sewers where such information

is available, or in the case where the depth is not known, approximate elevations shall be used

and noted as approximate. Each facility shall be properly identified.

25. ______ Proposed sewers shall be shown as double solid lines properly showing the height of the pipe.

26. ______ Open channel profiles with the proposed flow line, gradient, and the depth of special protection

(if required).

27. ______ The clearing distance between utilities is shown.

28. ______ The cover over the water pipe is shown.


Appendix B-8

ARCHITECTURAL SHEETS (If Applicable)

1. ______ Include a General Architectural Notes sheet.

2. ______ Include a Legends & Abbreviations sheet if required.

3. ______ Include Code Plans as applicable to the project.

4. ______ Include Floor Plans as required.

5. ______ Show Building Elevation and Section sheets depicting all applicable demolition, modification and

construction activities.

6. ______ Include Standard Architectural Details sheet as required.

STRUCTURAL SHEETS (If Applicable)

1. ______ Include a General Structural Notes sheet(s).


3. ______ Include Overall Plans and Sections if required.

4. ______ Include structural sheets for all applicable installations/equipment/structures that include:

a. ______ Pertinent dimensions.

b. ______ Type of concrete to be used.

c. ______ Type of metal to be used.

d. ______ Rebar size, location, numbers, spacing and clearances.

5. ______ Include a Standard Structural Details sheet.

PROCESS MECHANICAL SHEETS (If Applicable)

1. ______ Include a General Process Mechanical Notes sheet(s).


3. ______ Include an overall Process Mechanical plan if required. Plan shall include layout dimensions,

interior clearances, wall thicknesses

4. ______ Include Plans and Profiles of associated/affected Structures. In certain cases, more than one plan

or profile sheet may be required. All associated dimensions, and clearances shall be clearly called

out.

5. ______ Include Plans and Profiles of associated process equipment with dimensions, and clearances

clearly called out.

6. ______ Fittings, piping and valves shall be clearly marked. Pertinent fixtures, fittings, and supports shall

also be indicated.


Appendix B-9

7. ______ Call out pipe sizes, pipe material, and type of service (ex: 4-SS-AA for 4 inch Stainless Steel

Aeration Air service line).

8. ______ Call out valve size, valve type, and fittings (ex: 12-PV for 12 inch plug valve)

9. ______ Include a standard Process Mechanical Details sheet(s).

MECHANICAL SHEETS (If Applicable)

1. ______ Include a General Mechanical Notes sheet(s). Notes shall include applicable codes and

regulations.


3. ______ Include an overall Mechanical Plan sheet. This sheet shall include pertinent HVAC and Plumbing

sheets.

4. ______ Include separate sheet(s) for HVAC equipment. Sheet shall show locations of HVAC equipment,

clearances from other equipment, and include an HVAC equipment schedule.

5. ______ Include separate sheet(s) for Plumbing equipment, piping, fixtures, and fittings. When required,

plumbing sheets shall also include Plumbing Equipment schedule.

6. ______ Include a standard Mechanical Details Sheet.

ELECTRICAL SHEETS (If Applicable)

Depending on the nature of the project, it may be possible to combine some of these sheets.

1. ______ Include a sheet(s) for General Electrical Notes.


3. ______ Include an Electrical Site Plan as required.

4. ______ Include an Area Classification Plan.

5. ______ Include One Line drawings for the project.

6. ______ Include a Power and Instrumentation Plan.

7. ______ Include Riser Diagrams.

8. ______ Include Electrical Plan Sheets for each affected area.

9. ______ Include a Grounding Plan.

10. ______ Include Light Fixture Plan Sheets for each affected area.

11. ______ Include Electrical Plans for each affected area or process unit.

12. ______ Include Panelboard and Fixture Schedules if required.

13. ______ Include a separate sheet(s) for standard Electrical Details.


Appendix B-10

INSTRUMENTATION & CONTROL SHEETS (If Applicable)

Depending on the nature of the project, it may be possible to combine some of these sheets.

1. ______ Include a sheet(s) for General Instrumentation & Control Notes.


3. ______ Include a Systems Architecture sheet(s) if required.

4. ______ Include a P&ID sheet(s) if required.

5. ______ Include a sheet(s) for Loop Diagrams if required.

6. ______ Include a sheet(s) for standard Instrumentation and Controls Details.

STANDARD AND SPECIAL DETAILS

1. ______ Appropriate City of Shreveport Standard Details included.

2. ______ Special Details showing dimensions, material requirements, and other information necessary for

construction.

3. ______ Additional Standard Details by the Design Engineer to cover the scope and requirements of the

project.

EROSION CONTROL/ STORMWATER POLLUTION PREVENTION PLAN LAYOUT SHEET

1. ______ North arrow and scale.

2. ______ Silt fence length and location called out.

3. ______ Project limits.

4. ______ Project clearing limits.

5. ______ Existing contours.

6. ______ Stockpile areas are indicated on plan.

7. ______ Construction entrances are indicated.

8. ______ Best Management Practices locations and details.


Appendix B-11

COMMENTS AND NOTES

Appendix C-1

Appendix C

References Design of Wastewater and Storm water Pumping Stations, Water Environment Federation

Manual of Practice (FD-4), 1993

Recommended Standards for Wastewater Facilities, Great Lakes-Upper Mississippi River

Board of State and Provincial Public Health and Environmental Managers, 2004

Sewer System Infrastructure Analysis and Rehabilitation, EPA Publication (EPA/625/6-

91/030), 1991

Existing Sewer Evaluation and Rehabilitation, Water Environment Federation Manual of

Practice(FD-6), 2009 (3rd Edition)

The Guide to Short Term Flow Surveys of Sewer Systems (Water Research Centre

Engineering), 1987

The National Association of Sewer Service Companies Manual of Practice, 1995

Louisiana State Sanitary Code

City of Shreveport Water and Sewer Ordinances

City of Shreveport Fire Code

City of Shreveport Plumbing Code

City of Shreveport Standard Specifications

Shreveport Management Standards, Appendix 4.9B

Hydraulic Institute Standards

National Electrical Code

International Fire Code

Nation Fire Protection Agency

Louisiana Plumbing Code

Trenchless Technology Pipeline and Utility Design, Construction and Renewal 2005

ASTM A536 – Standard Specification for Ductile Iron Castings

ANSI A21.51 – Ductile Iron Pipe, Centrifugally Cast, for Water

AWWA Standards C51, C111, C115, C151, C512, C900, C905, C906, M22, M51

SSPWC Section 500

Appendix D-1

Appendix D

Design Phases

Key milestones of design phases are identified in this document. These milestones mark the

achievement of certain design goals which accompany delivery of pertinent documents. These

milestones are a conjunction of the City’s procedures and generally practiced standards.

Preliminary Design - 30% Completion The following activities occur during this phase of design:

The Design Engineer along with their key personnel shall conduct a kick-off meeting with the

City to review the scope of services, gather relevant data, and to understand the City’s

requirements and protocols.

The Design Engineer shall familiarize themselves with applicable codes, regulations and

requirements set forth by pertinent governing bodies. Where required, the Design Engineer

shall apply for pertinent permits, approvals and conduct environmental reviews.

The Design Engineer shall visit the site(s), and investigate existing survey and geotechnical

information, right-of-way maps, soil reports, master plans, field/lab data, record drawings and

all relevant technical reports in preparation for the design work.

During site visit(s), the Design Engineer shall verify that the current field conditions match the

record drawings.

The Design Engineer shall assist the City with Public Hearings if required. The Design Engineer

shall conduct additional Topographic Surveys, Geotechnical tests, and Special Investigations

(ex: pipeline inspections) as identified in the Scope of Services or as agreed upon during the

kick-off meeting.

The Design Engineer shall prepare all related calculations (Hydraulic, Process, Structural,

Electrical, etc)

If part of the scope, the Design Engineer shall evaluate design alternates available, along with

life-cycle cost estimates for each alternate.

The Design Engineer shall prepare preliminary plans (30% plans) based on the data gathered

and the calculations performed.

The Design Engineer shall prepare preliminary specifications for the design. A Table of Contents

(TOC), and an annotated outline of the specifications will be considered acceptable at this stage.

The Design Engineer shall submit the following documents to the City:

- A Design Criteria report as identified elsewhere in this manual. This may also be termed

‘Design Basis Memo’ or a ‘Preliminary Design Report’. This report shall include the

Appendix D Design Phases

Appendix D-2

following preliminary drawings: site layouts, Process Flow Diagrams (PFDs), Piping and

Instrumentation Diagrams (P&IDs), and Hydraulic Profiles. Preliminary Right of Way

(ROW) maps, sketch of survey lines, Geotechnical reports, all design calculations, and

results of special investigations shall also be included in this report. All design calculations

shall list the method used, assumptions made, values of constants used, and pertinent

references. If identified in the Scope of Services, this report shall also include design

alternates along with cost estimates for each alternate.

- 30% Plans that include the following preliminary plans: general sheets, standard details as

applicable to the project, site layouts, drainage and erosion control sheets, hydraulic

profiles, process mechanical sheets, PFDs, P&IDs, Instrumentation and Control (I&C) sheets,

pipe line routing concept with plan and profile views, and conceptual sheets by other

disciplines including mechanical, structural and electrical.

- A Quality Assurance/Quality Control (QA/QC) certification stating that all submittals have

been thoroughly reviewed by their QA/QC team, in accordance with their approved Quality

Management (QM) plan, for quality, accuracy, and scope. The Design Engineer shall include

copies of the QA/QC review documents and pertinent tracking sheets.

- 30% Design Specifications.

- A Class 4 (per Association for the Advancement of Cost Engineering or AACE) Opinion of

Probable Construction Cost (OPCC) estimate and an updated project schedule.

- The Design Engineer shall participate in a ‘30% Design Review’ meeting (also termed 30%

Plan-In-Hand meeting) with their Key Personnel and the City to discuss the City’s review of

the 30% design documents (30% Plans and Specifications).

Design Phase Sequence (condensed)

Design Development - 60% Design Completion Upon obtaining the final review comments from the City for 30% Design, Design Development or 60%

Design is considered to have started. The following activities are anticipated at this stage:

The Design Engineer shall update the design documents based on the City’s review comments

and design development.

Operability (with the City’s pertinent Operations team), Constructability and Value Engineering

reviews shall be conducted by the Design Engineer prior to submitting design documents.

Project Kick-Off

30% Design

Review Meeting

Design Criteria

Report

Finalize Design

Criteria

30% Design Documents,

Calculations, Class 4 cost estimate,

Updated Project Schedule


Appendix D-3

All survey efforts and ROWs shall be completed during this phase.

Any remaining or newly identified design calculations shall be completed.

Generally accepted design achievement levels for this phase are:

- Process Mechanical, Civil, Architectural and Geotechnical – minimum 75% complete.

- Structural, Electrial and I&C – minimum 60% complete.

- Building Mechanical – minimum 50% complete.

The Design Engineer shall submit the following documents to the City:

- Technical Reports if identified in the Scope of Services.

- Technical Memorandum identifying updates or changes to the design based on the

Operability, Constructability and Value Engineering review.

- Pre-Final Design Calculations.

- Finalized ROW maps shall clearly show all takings and servitudes required.

- 60% Plans with finalized site layouts, grading plans; coordinated plans. Process Mechanical

sheets, Hydraulic Profiles and Civil sheets shall be close to completion. All conflicts

(underground utilities, structures, etc) shall be identified at this juncture, and addressed.

Pipe routing, shall be near complete.

- 60% Specifications, including the ‘Front End’ documents. The Design Engineer shall verify

project and bidding requirements with the City when preparing the ‘Front End’ documents.

The Design Engineer is hereby notified that the City’s Standard Specifications may not be

applicable to all projects, therefore these specifications may need to be edited/updated as

required when incorporated.





- A Class 3 AACE cost estimate, and an updated project schedule shall be submitted along

with the 60% Plans and Specifications (60% design documents).

- The Design Engineer shall participate in a ‘60% Design Review’ meeting (also called 60%

Plan-In-Hand meeting) with their Key Personnel and the City in attendance to discuss the

City’s review of the 60% design documents.


Appendix D-4


Pre-Final Design - 90% Design Completion The Pre-Final design phase starts upon the Design Engineer receiving finalized review comments

subsequent to the 60% Design Review meeting. The following criteria shall be met at this stage:

The Design Engineer shall update the design documents per the City’s 60% review comments.

Overall project realization levels for this phase are:

- Process Mechanical, Hydraulics and Geotechnical – 100% complete.

- Structural, Mechanical, Architectural, Site Civil, and I&C – over 90% complete.

- Electrical – Over 80% complete.

The Design Engineer shall submit permit applications to various governing agencies per project

requirements.

The following documents shall be submitted to the City during this phase:

- Final design calculations per the requirements set forth in this document.

- 90% design documents (90% Plans and Specifications) for the City’s review. At this stage

the design is almost complete, and therefore the design documents shall be complete with

the exception of few updates, and coordination issues with other disciplines. The

Specifications shall be coordinated with the Plans so as to provide uniformity.





- A 90% Review Check List (included in this manual) shall be completed and submitted along

with the 90% design documents.

- A list, including but not limited to, required submittals, spare parts, warranty terms.

- A Class 2 AACE cost estimate, and a project schedule shall be submitted along with the 90%

design documents.

30% Design

complete

Submit Technical Reports

(if required), ROW maps

60% Design

Documents, Class 3

OPCC, updated

project schedule

60% Design

Review Meeting


Appendix D-5


Final Design -100% Design Completion At this stage all design is complete, and all of the City’s review comments have been incorporated. The

Design Engineer shall apply for any additional permits that may be required. Prior to issuing 100%

design documents, the Design Engineer shall submit 95% design documents for the City’s review. The

95% design set shall be complete in all aspects with the exception of the final stamp and seal, and will

be used by the City to do a final cross-check.

After approval of the 95% design documents, the Design Engineer shall submit the following:

- A completed final Review Check List (attached with this manual).

- Final design documents (100% Plans and Specifications). These shall be stamped and

sealed in accordance with the requirements of Louisiana Professional Engineering and Land

Surveying (LAPELS) board. The final design documents shall be accompanied by a written

certification from the Design Engineer stating that a detailed check was performed on all

previous review comments, and were addressed.

- A list, including but not limited to, required submittals, spare parts, warranty terms.

- An updated Class 4 cost estimate (final) shall be submitted along with the final design

documents.


60% Design

complete

Submit Permit

Applications


Final Calculations, Class

2 OPCC, updated project

schedule, 90% Review

Checklist, List of

submittals, spares,

warranty terms, etc.

90% Design Review

Meeting

90% Design

complete

Submit Permit

Applications

95% Design

Documents


Quality Review

Certification, Final Class 2

OPCC, List of submittals,

spares, warranty terms, etc.

100% Review Checklist.


Appendix D-6

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