plumbing and services training package -...

Plumbing and ServicesTraining Package

Learning Resource

Plan, size and layout stormwater drainage systems

BCPDR4002A

© Commonwealth of Australia 2005

TDS1:420 4Plumbing Lic Unit Res:Resources:MelAdmin:BCPDR4002A_Stormwater_drainage_systems:BCPDR4002A_Stormwater.doc 30-Jan-06

© Department of Education, Science and Training (DEST) GPO Box 9880 CANBERRA ACT 2601

Tel: (02) 6240 8111

All rights reserved. This work has been produced initially with the assistance of funding provided by the Commonwealth Government through DEST. This work is copyright, but permission is given to trainers and supervisors to make copies by photocopying or other duplicating processes for use within their own training organisation or in a workplace where the training is being conducted. This permission does not extend to the making of copies for use outside the immediate training environment for which they are made, nor the mailing of copies for hire or resale to third parties. For permission outside of these guidelines, apply in writing to DEST.

The views expressed in this version of the work do not necessarily represent the views of DEST. DEST does not give warranty not accept any liability in relation to the content of this work.

The website addresses and other contact information provided in this publication were compiled in good faith and were correct at the time of printing.

The National Plumbing and Services Training Advisory Group will monitor the resources for accuracy and currency annually. Requirements for upgrades will be translated to the relevant body.

© Commonwealth of Australia 2005


Acknowledgements

Project reference committee: National Plumbing Services Training Advisory Group

Project manager: Alexandra Mannell Holmesglen Training and Development Holmesglen Institute of TAFE Telephone: (03) 9564 1987

Writer: Peter Rintel

Technical editor: Adam Charles

Instructional designer: Judie Litchfield

Graphic artist: Laura Bito

Word processor: Melissa Rogers


© Commonwealth of Australia 2005 i


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Contents

Before you begin ............................................................................................................1 Introduction ....................................................................................................................5

1. Stormwater drainage systems: the basics ....................................................... 6 1.1 What should the system do? .............................................................................6 1.2 Commonly used terms .......................................................................................6 1.3 Catchment, rainfall intensity and runoff calculations .................................7 1.4 Some useful references .......................................................................................8 1.5 Relevant standards and codes ..........................................................................8 1.6 Local government requirements ....................................................................12 1.7 Other requirements ...........................................................................................13 1.8 Design concepts and performance measures as per AS/NZS 3500.3.2 .16 1.9 Material requirements ......................................................................................16

2. Preparation and planning ................................................................................ 18 2.1 Using a checklist ................................................................................................18 2.2 Define the project...............................................................................................20 2.3 Occupational health and safety ......................................................................22 2.4 Organising and sequencing work in conjunction with others.................27 2.5 Tools and equipment for planning ................................................................28 2.6 Preparing the workplace for planning..........................................................29 2.7 Preparing for on site testing ............................................................................30 2.8 Preparing a bill of quantities (quantity surveying) ....................................31 2.9 Quoting the works.............................................................................................31 2.10 Levelling............................................................................................................32

3. Types of drainage systems............................................................................... 34 3.1 Conventional systems.......................................................................................34 3.2 Rainwater reuse systems..................................................................................36 3.3 Combined allotment drainage ........................................................................37 3.4 Pumped systems................................................................................................38 3.5 Charged systems................................................................................................39


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3.6 Aquifer storage .................................................................................................. 41 3.7 On site stormwater detention......................................................................... 41 3.8 On site absorption............................................................................................. 42

4. Identifying system requirements....................................................................44 4.1 Plans/specifications ......................................................................................... 44 4.2 Regulations and standards ............................................................................. 45

5. Designing the system ........................................................................................47 Am I familiar with the pipe system selected for the job? ................................... 47 5.1 Sizing the layout................................................................................................ 47 5.2 Drawing the layout........................................................................................... 52

6. Restoring the work area....................................................................................55 6.1 Restoring the worksite ..................................................................................... 55 6.2 Maintenance and storage of tools and equipment..................................... 56

7. Documentation ...................................................................................................58 7.1 Domestic and commercial documentation requirements ........................ 58 7.2 Delays in documentation ................................................................................ 59 7.3 Receipt of documents ....................................................................................... 59 7.4 Document security............................................................................................ 60

Final assessment activities.......................................................................................62


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Before you begin

Welcome

Welcome to the learning resource for the unit BCPDR4002A Plan, size and layout stormwater drainage systems. This resource will help you develop the knowledge and skills you need to demonstrate competence in this unit.

A learning resource such as this is not intended to be the only source of information you use to develop skills and knowledge in the unit it relates to. Your trainer, instructor or supervisor will provide you with additional information and information sources throughout your training.

Flexible delivery

Your trainer, instructor or supervisor for the unit may adapt and deliver this learning resource as required to suit people from a range of backgrounds and in diverse learning environments (such as rural and isolated settings). This will assist in meeting equity principles and conforming to legislative policies.

How to use this resource

This resource addresses the underpinning knowledge and skill development required to help you plan, size and lay out stormwater drainage systems. It contains: • information on planning, sizing and laying out stormwater drainage

systems • activities designed to encourage you to check and confirm your

learning along the way and to help you complete the final assessment

• a summary of the final task or tasks you must complete to be assessed as competent in this unit. Your assessor will give you additional specific detail required for your final assessment activity in line with state and territory regulations and industry requirements.


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The resource has been developed for use in a variety of ways. Your trainer, instructor or supervisor will advise on how best to use it during your training, which may include: • teacher-centred, class-based study • home-based, self-directed study • activities in the workplace.

To complete the unit BCPDR4002A Plan, size and layout stormwater drainage systems, you may be required to: • read the information in this resource

• complete the resource activities as directed and submit your answers for review or discussion with your trainer, instructor or supervisor

• work with your trainer, instructor or supervisor to practise planning, sizing and laying out stormwater drainage systems

• read the final assessment summary together with any additional assessment information your assessor provides

• complete the final assessment.

Your assessment in this unit

It is important to note that the role of the assessor in assessing units of competence is quite separate from the role of trainer, instructor or supervisor. Your assessor for this unit may or may not be the same person as the trainer, instructor or supervisor who worked with you during your training. However, your assessment must always meet the requirements of the unit. You will find references to trainers, instructors or supervisors and assessors throughout this resource depending on the context.

Assessment in this unit will require you to demonstrate the skills and knowledge needed to plan, size and lay out stormwater drainage systems. Table 1 on page 3 suggests the variety of assessment methods that may be used to assess your competence in this unit. In many instances, your assessment may involve a combination of methods to ensure the validity, reliability, flexibility and fairness of the process. If you have any questions about your assessment please discuss them with your assessor who will decide with you the specific details of what you will do. An assessor may develop specific assessment strategies to meet the particular requirements of learners from diverse backgrounds.

This unit may be assessed in conjunction with assessment for other units of competence. In such a case assessment might be based on a task or tasks related to a project that more closely resembles workplace activities. Your assessor will decide if you are to be assessed in this way and will advise you.




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Assessment methods

Key Assessment method

Description

QS Questioning oral/written

Assessor will ask a range of questions from a moderated bank of questions that support the underpinning skills and knowledge required to achieve competency in this unit. Questions may be answered in written or oral form.

WN Written notes Learner will complete written notes, activities or student resource materials to support the achievement of underpinning knowledge required to achieve competency in this unit.

TB Test bank Learner will complete computer test bank assessment which supports the underpinning skills and knowledge required to achieve competency in this unit.

PO Practical observation

Assessor will observe the learner completing practical task(s) that meet the assessment criteria to the required specification in the workplace.

DM Demonstration Assessor will observe the learner completing practical task(s) that meet the assessment criteria to the required specification in a simulated work environment.

CS Case study/project Learner will complete workplace-based projects or case study reports to support the underpinning skills and knowledge required to achieve competency in this unit.

LB Logbook Learner will provide evidence of practical work and/or assessment tasks completed at the workplace via personal logbook.

3P Third party report Assessor will seek report from learner’s workplace employer, supervisor or other approved party on the performance of a learner in the workplace against assessment task criteria and requirements of the unit.

WD Workplace documents

Learner will provide copies of workplace documents to support the underpinning skills and knowledge required to achieve competency in this unit.

Table 1 – Assessment methods




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Prerequisites units

There are no prerequisite units for this unit.

Additional resources

The following resources have been suggested that may help you undertake training and assessment in this unit.

Texts • AS/NZS 3500.3.2:1998 Stormwater drainage – Acceptable solutions.

Note that this Standard has been updated in 2003, however, both versions are in use.

• SAAHB39-1997 Installation code for metal roofing and wall cladding • Australian Rainfall and Runoff, The Institution of Engineers Australia,

Barton, ACT

Websites • www.pic.vic.gov.au • http://natindex.nohsc.gov.au/about.asp • www.safetyline.wa.gov.au • www.standards.org.au • www.upret.nsw.gov.au • www.masterplumbers.com/plumbview/2000/stormwater.asp

Video or audio resources • Nil.




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Introduction The population is generally unaware of the many systems that allow everyday life to continue. Efficiency is assumed. Stormwater drainage systems fit into this category. Yet without the planning and consultation underpinning the efficient operations of these systems, public confidence would be eroded.

In this unit, we will discuss what is needed to plan, size and document the layout of surface and subsoil stormwater drainage systems up to the points of connection. You will cover preparing for planning, identifying and confirming system specifications and requirements, planning the system layout and work finalisation processes including records and documentation.

For assessment, you will plan, size and document the layout details of a surface and subsoil stormwater drainage system for each of the following: • a residential unit development of at least five two-storey (Class 1)

units • a commercial (Class 5) building.

The systems should include drainage to the point of connection to the external stormwater drainage network (or the legal point of discharge).

Your work in this unit will ensure you correctly identify details of the plan, as well as select and use appropriate processes, tools and equipment. You must complete all work to specifications. Your work must also comply with all regulations, standards and organisational quality procedures and processes.




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1. Stormwater drainage systems: the

basics

1.1 What should the system do? Rain falling onto a surface creates stormwater which then takes a path following the contours or fall of the collecting surface. In a parkland, the flow might simply follow the undulations of the ground. On a constructed property, the roofing material, gutters and the paved surfaces (driveways, paths, etc) determine the water’s path.

The drainage system for such water should collect the water without affecting the property, residents, visitors or adjoining properties. Most systems then discharge all or some of the collected water by gravity to the external drainage network.

1.2 Commonly used terms Water collected from roofed areas is called roof water. Water from paved and unpaved areas is surface water. Water in water-bearing ground is termed subsoil water.

Subsoil water can be:

• a flow from an adjoining property • water trapped against a brick wall and its foundations • water that collects at a low spot.

A subsoil drain is the conduit of a stormwater installation laid underground for the collection and passage of subsoil water to a stormwater drain.




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1.3 Catchment, rainfall intensity and runoff calculations

Note

See AS/NZS 3500.3.2 for detailed information.

To design a piped system, we must calculate as closely as we can how much water will collect on the site in a given time.

Clause 5.2.3 (page 53 of the Standard – Design rainfall intensity) relates to designing a system that can cope with minor storms. It calls for all elements (surface drains, gutters, formed flow paths) to be capable of containing such events at average recurrence intervals (ARI) as set out in Table 5.1 (page 56). Surface drainage systems must also ensure overflows during storms with an Australian ARI of 100 years do not endanger people or significantly damage property.

Accepted design criteria for a system that drains all roofing and other hard surfaces (paving, driveways, etc) via a gravity flow system are: • recurrence interval – 20 years • time of concentration – 5 minutes • rainfall intensity – depends on location

(eg Perth = 140 mm/hr, Sydney = 210 mm/hr) • coefficient of runoff – pervious 0.75, impervious 1.00.

Calculations for a storm of 1:100 average recurrence interval depend on location (eg Perth = 210 mm/hr, Sydney = 270 mm/hr).




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1.4 Some useful references • Rainfall intensities – Five minute duration are listed in

AS/NZS 3500.3.2003 Appendix E (page 106). • Roof water, catchment area, calculations – See AS/NZS

3500.3.2 section 3 (page 20). • Surface water, drainage systems design – See AS/NZS

3500.3.2 section 5 (page 53). • Subsoil water, drainage system design – See

AS/NZS 3500.3.2 Appendix M (page 175). The information in that appendix is only ‘informative’ (for information and guidance only). You may need an engineer to design your drainage system but your work experience and skills in calculating levels and falls can let you set the grade of the drain to the collection point. Then, drawing on manufacturer plans/specifications showing pipe capacity, you should be capable of designing and installing a system.

1.5 Relevant standards and codes

Note

The underlying reference for any design or need for interpretation in the material covered by this unit is the Standard AS/NZS 3500.3.2 Stormwater drainage.

What is a standard?

Australia and New Zealand through the Reciprocity Association together produce rules plumbers must adhere to in their work. AS (Australian Standard)/NZS (New Zealand Standard) 3500 is the designated number for plumbing and its disciplines. Thus, AS/NZS 3500.3 is the guide for stormwater and the year 2003 is when this Standard was published.




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Sometimes, there are minor differences between the ‘local rules’ of the two countries and these are noted in the standards. This enables a plumber from (say) New South Wales to apply to his local registration authority for a Certificate of Reciprocity, pay a registration fee and then use the certificate to work elsewhere in Australia or New Zealand, using a familiar set of rules (AS/NZS 3500).

In Australia, The Standards Association publishes the ‘rules’ and amendments, ensuring at all times that plumbers have an up to date reference.

Relevant standards/codes for stormwater drainage

AS/NZS 3500.3.2003 is the reference code/Standard that all authorities refer to for the design and installation of stormwater drainage systems. See also AS/NZS 3500.2.2 Sanitary plumbing and drainage – Acceptable solutions.

For determining the class of building, see The Building Code of Australia: • Section A General Provisions • Part A3 Classification of Buildings and Structures • Appendix A.

Some authorities/councils refer to the Australian rainfall runoff data produced by the Institute of Engineers. This should be read and used in conjunction with AS/NZS 3500.3.2.

The Standard HB 114 has also been produced as a simplified explanation of AS/NZS 3500.3.2 to assist roofing installers in determining the sizes of gutters, downpipes and dimensions of acceptable overflow methods. It is to be read in conjunction with AS/NZS 3500.3.2. Both Standards use the design method known as the general method.

Some authorities refer to the Institution of Engineers’ publication Australian Rainfall and Runoff as the design guide but you should read this in conjunction with AS/NZS 3500.3.2003.

Other relevant standards and codes include: • HB 39 Code of common practice for steel roofing:

Finished surface levels, drain depth levels, finished height and depth of pits etc, materials and measuring quantities are all to the Australian Standard Method of Measurement of Building Works (AS 1181 1982).




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• AS 1742.3 1996 Manual of uniform traffic control devices. • AS/NZS 3845.1999 Road safety barrier systems.

• HB 81.1 2003 Field guide for traffic control at works on roads – Short-term urban works, measurement of building works (daytime only).

Note

Standards Australia has a website where you can locate a ‘standard’ for everything – manufactured goods, measurements, processed food, etc. At time of writing, contact details are <www.standards.org.au>, or telephone Standards Australia Customer Service on 1300 654 646.

List of authorities

Australia-New Zealand Reciprocity Association PO Box 360 CAULFIELD EAST VIC 3145

New Zealand Registrar Plumbers, Gasfitters & Drainlayers Board PO Box 10655 WELLINGTON NZ

Ph: (0011) 64 4494 2970 Fax: (0015) 64 4494 2975

Australian Capital Territory Deputy Registrar Plumbers, Drainers & Gasfitters Board of ACT PO Box 1908 CANBERRA CITY ACT 2601

Ph: (02) 6251 3655 Fax: (02) 6251 3606

New South Wales Manager Licensing Office of Fair Trading PO Box 975 PARRAMATTA NSW 2150

Ph: (02) 9895 9996 Fax: (02) 9895 9918




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Northern Territory Registrar Northern Territory Plumbers & Drainers Licensing Board GPO Box 1680 DARWIN NT 0801

Ph: (08) 8999 7152 Fax: (08) 8999 8967

South Australia Manager Business and Occupational Services GPO Box 1719 ADELAIDE SA 5001

Ph: (08) 8204 9660 Fax: (08) 8204 9678

Queensland Chairman Plumbers & Drainers Examination & Licensing Board GPO Box 408 FORTITUDE VALLEY QLD 4006

Ph: (07) 3235 4123 Fax: (07) 3235 4586

Victoria Registrar Plumbing Industry Commission 450 Burke Road CAMBERWELL VIC 3124

Ph: (03) 9889 2211 Fax: (03) 9889 2244

Tasmania Plumbers & Gasfitters Registration Board 144 Tarleton Street EAST DEVONPORT TAS 7310

Ph: (03) 6429 8489 Fax: (03) 6427 9327

Western Australia Executive Officer Plumbers Licensing Board Department of Consumer & Employment Protection Locked Bag 14 CLOISTERS SQUARE WA 6850

Ph: (08) 9282 0476 Fax: (08) 9282 0863

Table 2 – Listing of relevant Australian/New Zealand registration authorities

(from the Australia-New Zealand Reciprocity Association)




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1.6 Local government requirements

Each local government area also has its own requirements/ by-laws, all designed to comply with AS/NZS 3500.3.2003.

Examples

City of Nedlands (WA) <www.nedlands.wa.gov.au>: Requires all stormwater falling on a lot to be contained on site and dealt with by soak-wells or other approved methods.

City of Ryde (NSW) <www.ryde.nsw.gov.au>: A guide for the design of ‘Charged Stormwater Drainage Systems’ (where flow to the legal point of discharge is achieved by syphoning). The site has examples of the detailed plans the City of Ryde requires, including longitudinal section details.

City of Port Phillip (Vic) <www.portphillip.vic.gov.au>: Port Phillip regulations include one relating to ‘the position and manner of discharge’, which must be ‘to the satisfaction of the local Authority’. System design must ensure that any overflow during heavy rain cannot flow back into the building.

Mosman Municipal Council (NSW) <www.mosman.nsw.gov.au>: This website has a comprehensive guide Guidelines for Stormwater Drainage Systems, covering all the aspects of stormwater drainage you are likely to encounter.

All councils have uniform requirements of detailed plans to be submitted for approval. These include: • position of any easements on the allotment • composition of drains, ie PVC, FRC, reinforced concrete • location and design of pits • number of downpipes • method of connection to the legal point of discharge • contours of the land to show the topography/lie of the

allotment • reduced levels (RL) – the height or elevation above a given

point adopted as the reference point to which your system will be installed.




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Sometimes you must attach your calculations for the proposed system to your submission.

1.7 Other requirements

Environment protection authorities

The Environment Protection Authority in your state requires safeguards to minimise risks to water quality (eg through spills of contaminants) and other environmental damage. Such safeguards can be a ‘bund’ which is a small wall around liquid storage cylinders in the open. WaterCare, South Australia Fact Sheet No 9 sets out an example of such requirements.

The two diagrams that follow give you an idea of how a bund works. (The drawings are adapted from EPA Victoria and NSW EPA material.) These drawings show how uniform EPA regulations are on this aspect of stormwater across the states and territories.




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Figure 1 – Environmental requirements for ‘bunding’




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Where hazardous materials are stored on site, environmental authorities also require that the outlet of the property’s stormwater drainage system can be sealed off if an accident or spill occurs. Such on site containment allows clean up without the contamination or hazardous materials entering the local drainage system. Without such containment, massive pollution further along the drainage system can occur. You may also need to consider clean up issues.

Local sewerage authorities

The trade waste department of your local sewerage authority has requirements for ‘first flush’ precautions. An example would be precautions for an unroofed impervious area where effluent from an activity such as hosing down horses is discharged to the sewerage system during rain. The authority may require a valve that activates automatically so that flow from the area is discharged to the stormwater system during rain.

The Marwill method

One means of isolating a stormwater drainage system when a spill occurs is the ‘Marwill’ method (see Figure 2 below). With this method, the stormwater outlet is sealed off where the drain discharges into a river. In the example shown, the river is the Maribyrnong in Melbourne.

The same system is used for isolating the discharge from horse stables into the sewerage system (as described above). When rain begins, the ‘first flush’ is dealt with then the sewerage connection is shut off and the rainwater flows into the stormwater system.

Figure 2 – The ‘Marwill’ method of isolating a stormwater drainage system when a spill occurs




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1.8 Design concepts and performance measures as per AS/NZS 3500.3.2 There are two methods of design for stormwater drainage systems: the nominal and the general.

1. The nominal method: For a single dwelling (rural or urban) on an allotment less than 1,000 m2, calculations are not required but requirements for pipe diameter, grade and layout as well as depth of cover must be followed. (See clause 5.5 on page 67 of the Standard.)

2. The general method: A system for a single urban dwelling on an allotment more than 1,000 m2, or for a commercial/ industrial development requires calculations and pipe hydraulic design procedures (clause 5.4, page 55).

The preferred point of discharge for stormwater and subsoil drainage is the connection point at an external drainage network. Where this is not possible, stormwater should be discharged to a natural drainage system in an appropriate way or to a rubble drain or transpiration bed. Stormwater must not be discharged in a way that allows ponding or concentration on adjoining properties and it must not be allowed to enter buildings.

1.9 Material requirements Products and materials are continually being created or changed to make them more cost-effective and to make the life of the end user (you, the plumber) easier. Thus, the manufacturer of a smart, inexpensive, easy-to-install drainage system is the one who will have your business.

There are also situations where you must use a certain product. This could be when there is minimal cover over a drain or an authority requires a drain inside a building to be of reinforced concrete.




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In all types of systems, joints and jointing materials must comply with AS/NZS 3500.3.2 and the relevant standards, but you may choose from a variety of materials. These include: • UPVC • reinforced concrete • cast iron • PVC fusion weld pipe and fittings • geotextiles • vitrified material.

If you are designing the job yourself you can choose what product you will use. Otherwise, the job plans and specifications will specify sizes and materials.

AS/NZS 3500.3.2 Table 4.6 (page 50) lists the permissible joints for components of similar and dissimilar materials.

It is difficult to select products as samples to present in this resource without favouring one product over another. So far in your working life you will have been exposed to a variety of products and this will continue. The following list of manufacturer websites may provide you with additional information to explore: • www.jameshardiefrcpipes.com.au • www.crevet.com.au

• www.bluescopewater.com.au • www.vinidex.com.au • www.iplex.com.au • www.ribloc.com.au • www.myhumes.com.au • www.rocla.com.au • www.geofabrics.com.au.




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2. Preparation and planning

To plan, size and lay out a stormwater drainage system, you need specific skills and considerable knowledge. Essential elements include planning, levelling, calculating materials, quoting, installation methods, occupational health and safety, documentation and end-of-job procedures. We will discuss each of these in more detail later.

Completing the tasks in this section provides you with an overview of the planning for the work on stormwater drainage systems. The overview ranges from preparation before the work begins and includes plans that will be in effect throughout the work. Ask if you have any questions about the process. Remember that planning should cover every aspect of the stormwater drainage task. Sound preparation provides a solid base for all future work.

2.1 Using a checklist Attention to detail is vital to good planning. You should always write, print clearly or type a checklist that covers every part of the project, but however you do it, filing and storing information and calculations in an orderly way will help you build a clear understanding of the job.

What makes a good checklist?

A checklist and orderly information file lets you refer back at any time for confirmation of specific details. That way, you will know if you have taken into account a particular component, how much you allowed for a particular item or who was your contact at the authority or supplier, etc. If your writing or set-out for your list and notes is not clear you inevitably lose time going back over everything to find what you need.

The checklist that follows suggests the range of information you need to consider during the planning stage of any stormwater drainage project.




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A checklist for planning a drainage system • Who is the authority/council contact? What are the requirements? • Where is the legal point of discharge? Is there a connection fee?

• Do you have a plan of the external drainage system (subdivision plan)? What other plans will you need?

• Do you have a road/nature strip opening permit? • What inspections will the local council require during installation? • What other services are in the area? Remember: dial before you dig,

1100.

• Have you done site tests? • What by-laws/standards cover the works? • Insurance:

− Public liability: How much will you need? What cover does the council require for road opening? (Some have requested $5 million.)

− Personal accident: How much will you need? How many extra workers will you need to cover?

− Materials: How much cover will you need (eg, for materials stored in a compound)?

• Bill of quantities: − pipe, pit material quantities − sand and gravel quantities and supplier − hire equipment − excavator − additional labour.

• Contact details for: − building owner − architect − builder and site foreman.

• Onsite materials storage. Do you need a compound? • Washing, toilet and lunchroom facilities for workers. • What tools and equipment are needed? • Where is the datum? (This is discussed in more detail in the section

on levelling.)

• Fall of land. • What other trades will you need to liaise with? • Work schedule. • System calculations.




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2.2 Define the project Your first task will be to identify the nature and scope of the planning needed for the project. You need to view the following documents before work begins: • plans/specifications • stormwater disposal plans

• legislative, regulatory and Standards requirements relevant to your state

• manufacturers’ instructions • instructions from authorised organisational and external

personnel.

You will also need to prepare for the documentation that must be completed during the course of the work. This documentation includes: • written instructions • signage • work schedules • Material Safety Data Sheets (MSDS) • job drawings

• work bulletins.

Forethought and preparation will ensure you identify and confirm the nature and scope of planning for the task.




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Activity 1

There is a large amount of paperwork, computer files and oral information created in planning the size and layout of a stormwater drainage system. Think about how and where you will store this information. Write out your ideas in the space provided.




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2.3 Occupational health and safety

Occupational health and safety (OH&S) regulations and procedures need to be considered in your preparations. Your plans for OH&S should cover what is needed from the preparation stage right through to job completion.

All tasks during the course of the works must be carried out in accordance with the appropriate OH&S requirements. Failure to observe these regulations can result in heavy fines.

Requirements include: • having operators of heavy equipment licensed • risk assessment (looking at the possibility of injury or harm

occurring to a person if exposed to a hazard) • hazard identification and control. A hazard is anything that

may result in injury or harm to health. Hazard control requires you to identify and minimise potential dangers, eg risks associated with tools, equipment and machinery, tripping, underground services, the building itself, hazardous materials and working at heights, near other people or in confined spaces. You must also consider the safety of worksite visitors and the general public.

Key issues

Key OH&S issues to consider on stormwater drainage projects include: • appropriate use of personal protective equipment (PPE) • safe use and storage of tools and equipment • workplace safety and environment • handling of materials • additional skills, such as a dogging license or load slinging

training, may be required to safely move drainage pipes on site

• use of fire fighting equipment • use of first aid equipment • storage of first aid equipment on site • washing and toilet facilities on site • safe operating procedures • disposal of hazardous waste

• hazard identification and control.




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Generally, you will need to compile a Safe Work Method Statement/JSA for the project.

OH&S resources

The nature of the tasks and equipment for the work covered in this unit have unique OH&S requirements. At the time of writing, the following websites provide an excellent source of up to date information for you on those requirements and relevant issues.

The National Occupational Health and Safety Commission

http://natindex. nohsc.gov.au/about. asp

For information about your state’s requirements, key in ‘Drainage Excavation’ at ‘key word’, and sites from around the country are listed.

Manual Handling Solutions Plumbers (Water, Drainage, Gas, Sanitary and Maintenance)

www.safetyline.wa. gov.au

The document is a concise nine page download with excellent content for plumbers.

WorkSafe Victoria – administers the Occupational Health and Safety Act, 2004

www.workcover.vic. gov.au

OH&S procedures may vary for different workers at your worksite. You need to be familiar with all the recommendations.

Code of Practice: Excavation (NSW)

www.workcover.nsw.gov.au

A booklet that alerts plumbers and excavators to the hazardous situations that can occur on a site during excavation.

Table 3 – Listing of relevant websites containing OH&S information




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Excavation

Excavation is an OH&S hazard particular to drainage projects. The Code of Practice: Excavation (NSW) noted in the previous table is a good guide to assist plumbers safely carry out the many tasks associated with excavation. The document covers issues such as: • situations to be aware of when carrying out the tasks

involved in installing a drainage system • types of shoring that may be used.

The following graphics (taken from the Code of Practice: Excavation [NSW]) highlight the pitfalls that can occur if trucks or heavy vehicles are located too close to trenches. Not surprisingly, trench edges can give way under the vehicle’s weight if the chosen method of shoring doesn’t adequately support the trench walls under heavy loads. Even shallow excavations can have similar pitfalls and so similar rules apply for safety and ease of installation throughout the job.

Figure 3a – Shoring designed for surcharge loads

.




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Figure 3b – Shoring designed for soil loads only

Figure 3c – Limiting approach for equipment

Figure 3d – Spoil altering depth of trench




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Figure 4a – Soldier sets: Timber steel, proprietary

Figure 4b – Precast panels

Figure 4c – Full timber system Figure 4d – Sheet piling

Figure 4e – Trench shields Figure 4f – Rock bolts




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Activity 2

You are required to obtain a blank sample Safe Work Method Statement (Job Safety Analysis) sheet. You may choose to use a sample from your own workplace or follow the sample provided in the resource for the unit BCPCM4001A Carry out work based risk control processes which you should have already completed.

Complete the document and list the potential hazards you would identify during the process of planning a stormwater drainage system and the risk control measures you would use.

Submit the completed form to your trainer/instructor/supervisor for discussion.

2.4 Organising and sequencing work in conjunction with others Plumbers will not be the only workers who contribute to planning the size and layout of a stormwater drainage system. As in any job, preparation is needed at the outset when others are involved.

Consider the following list of people/organisations who may need to be contacted for information or scheduled into the operation: • local authority/council (for information on requirements

and inspections)

• surveyors (may be needed to provide a datum, to set out property boundaries and record heights of installation)

• engineer, authority/council (OH&S issues – eg, your shoring method might need verification)

• geotechnical engineer (for advice on soil types and proposed methods of subsoil drainage)

• architect (for conference on proposed heights of surface finishes, collection points of surface drainage)

• ‘Dial before you dig’ 1100 (for location of existing services)




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• workforce (for a range of reasons – eg, assisting in setting

up site shed and going over the work schedule. ‘Bouncing’ ideas around can highlight potential problems before they happen.)

• OH&S inspector (ensuring work practices are in order; hazards are identified, manual lifting procedures have been taught, nominated first aid officer and locations of first aid kits has been advised, etc)

• concrete supplier, for an opinion on delivering concrete to the site after excavation (Can their trucks handle the soil?)

• draftsman (to draw up plans quickly and efficiently for the relevant authority/council)

• arborist (if excavations threaten the stability of a tree or much-loved shrub

• roofing plumber (if you did not install the roofwork and you commence the drainage, all downpipes and overflow relief provisions need to be in place or works must continue while you carry out your tasks)

• sand and screening supplier. (Can the supplier’s vehicles access the site?)

You will need to communicate with others to determine the best sequencing for the work. Establish an effective communication system with all who have an input and document the outcome. You may need to document any verbal communications in writing.

When your plans are completed, you may need to check with others to confirm the organisation and sequencing of the work. You might know a clerk of works, builder or site foreman who would offer advice and pass on pieces of information that will be invaluable to you for this project and future projects.

2.5 Tools and equipment for planning Even at this early stage, you will need specialist tools and equipment to assist you in your task. You have already made provision for personal protective equipment and document/file storage.

Other specialist equipment you will need on hand includes: • drawing instruments • drafting and drawing materials • measuring instruments, including laser measuring devices

• ladders




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• photocopiers • computers running appropriate design-aided software

• two-way radios or mobile phones • drain dye (for pouring down existing drains to evaluate

flow and if there are blockages etc) • calculators • camera, preferably digital (for recording before and after

situations) • laminated board, approximately 700 mm x 700 mm (taping

plans, diagrams, etc to a board makes on site drawing/sketching much easier)

• Teledex, card holder etc (with contact details of every person involved in the project).

2.6 Preparing the workplace for planning Think about what is needed for efficient planning and the type of environment that is best for the task. For example: • sufficient lighting • OH&S compliance • proximity to the worksite

• effective communication system • adequate workstations • sufficient storage for tools, equipment and documentation.

Tasks associated with planning and preparation are often conducted on site. At times it may seem as though you have a mobile office but it is important to have an established base that meets all the requirements for good planning. This base should be easily accessible to (but not necessarily at) the worksite.

A poor workplace environment may produce a poor result. Make the preparation of that environment an important aspect of your overall preparation.




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2.7 Preparing for on site testing As you will see from the following task list, much preparation for preliminary testing may need to be done at the drainage system worksite before any work commences: • The connection at the legal point of discharge must be

inspected, with notes made and photographs taken. You must check it visually and also check discharge water (coloured for easier observation) to look for obstructions to the flow.

• Telephone the ‘Dial before you dig’ service on 1100. This is vital for checking the location of other services. Again, photographs can be a useful record.

• As discussed earlier, if you did not install the roofwork you will need to inspect it to check for the correct number of downpipes and the provisions for overflow relief if needed. That is, if the gutters overflow the water must not flow back into the building or under it.

• Test any internal downpipes for leaks. • Suspect patches of ground that are damp or shift under

your feet will need excavation to check that they are not holding water or that the area has not been backfilled with rubbish.

• If your task is remedial drainage work on a building, then a small moisture meter will be handy to test brick footings, walls, etc for rising damp. Plotting the line of dampness can also indicate its origin. You can track the subsoil seepage by observing the lie of the land and the wettest areas of brickwork.

• Trees or shrubs that must be retained on site and trees on council property must be checked by an arborist before any excavation near them. Even planning the line of drainage must take into account any potential damage to the tree from root disturbance.

• Test holes must be dug along the neighbouring fence lines if the ground slopes into the property from the fence. This is so you can check the depth of moisture in the test holes. The council may require you to dig a test hole, fill it with water and record how long it takes for the water to disappear.




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2.8 Preparing a bill of quantities (quantity surveying) Your ability to accurately measure and estimate (lengths, cubic metres, depths, heights, labour times, etc) is essential in determining ‘how much’ for all elements of a job. Many tradespeople take this skill for granted and far too often ‘under-allow’, which affects the final profit or loss outcome for the job. Allowances must include: • council fees and permits • fees paid to consultants • the type of pipework and how much is needed for the job • the number and type of pits

• allowance for the excavator • whether spoil is to be carted away (and if so, the cost of tip

fees) • pipe bedding (sand/crushed rock) • concrete (if required) • equipment hire (jackhammers, protection barriers etc) • additional labour.

2.9 Quoting the works How you present your quotation is vital to the impression you make on your client. Along with how you present yourself, a quotation that is clear, concise and well presented instils confidence and makes the client more likely to select you as the contractor for the job.

From the schedule and bill of quantities, you will be able to prepare a quotation in a professional way, listing the works to be carried out and the time needed to deliver a ‘working system’.

Note

For a clearer understanding of preparing a bill of quantities and quoting on plumbing works in general, refer to Paul Funnell’s book Estimating for Plumbers. You should also review the unit BCPCM4002A Estimate and cost work.




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2.10 Levelling Levelling requires you to find out or calculate the required height and/or depths of drainage and the amount of fall over the land.

In preparing a plan for approval, you must indicate the proposed depth of drains and pits. To determine these, you will need to understand the relevance of a range of figures noted on the subdivision plans you get from the authority.

Terms used

Contour line – a line that indicates points of equal height, generally spaced at one-metre intervals on construction drawings.

Datum – a horizontal plane of known height to which the elevations of other points can be referenced. The mean sea level is the level surface generally adopted as a datum. The Australian Height Datum (AHD ) is based on the mean sea level determined by the tide gauge readings around the Australian coast.

Reduced level (RL) – the height or elevation above a given point, adopted as a datum.

Determining levels

All your planning and designing must take into account the site’s topography – that is, its ups and downs or ‘site relative’ levels. If you are good enough at drawing, you can show on your plan the line of contours. This helps greatly in your planning as it lets you see more easily how much fall you have to work with.

Your proposed plan can show a datum (or starting point) of 00.00 (zero) taken from a stable point, invert level of external drainage or the top of the authority’s pit. To establish the required depths for your drainage system, you can work back from the datum point.




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Worked example

In this example the levels are as follows: • top of pit = 00.00 • invert of drainage pipe in property at boundary = 00.100.

Your pipe invert level is to finish at the boundary of the property 100 mm above the top of the pit. Further into the system, you can show a pit in the driveway where the invert level of the pipe is 00.250. This indicates to the authority approving the design that this is 0.250 mm above their pit.

Figure 5 – Documenting reduced level




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3. Types of drainage systems

This section describes the main stormwater drainage systems you will come across. They include gravity, pumped and displacement-operated types.

3.1 Conventional systems In a conventional system, the roof catchment and site drainage water is collected and conveyed by underground pipes to a legal point of discharge.

Such a system is ‘conventional’ in that it represents accepted trade practice for construction and installation of a stormwater drainage system.

Figure 6 that follows shows a small section of a drainage plan for a primary school in a Darwin suburb. The plans were drawn up by the Commonwealth of Australia, Department of Housing & Construction, South Australian Region, for the South Australian Department of Education.

If you study the figure carefully, it will help you understand how drainage plans are drawn and to understand system layouts.

The main drain is 525 mm RCP (reinforced concrete pipe). You can see it at the bottom right-hand corner where it joins up with a larger council-owned main drain discharging into one of the creeks in the area that flow into the ocean.

You should also note the following significant features: • The RL height of the drains from pit 16 is shown as

IL 32.320.

• The inlet height of the drain is shown as IL 32.620, while the finished height of the pit is 33.950.

• The fall of pipe 450 RCP from pit 16 to pit 2 is 145 mm over 18 metres.

• Finished impervious (concrete) path heights are shown underlined (ie 34.100). This standard of measurement (as with the height measurement for drainage) is used in all the project’s drawings.

• Precise, clean and clear lines are a feature. Even though the plans are old, following the design and layout is easy!

• Visual inspection of the site would show all overflow relief from railheads discharges onto paved areas or garden beds that fall away from the buildings.




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Figure 6 – Section of a drainage plan for a primary school (Plan drawn by the Commonwealth Department of Housing & Construction, South Australian Region)




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3.2 Rainwater reuse systems In a rainwater reuse system, the roof catchment is collected in onsite storage tanks and surface water is conveyed to a legal point of discharge by underground drains.

Figure 7 – A rainwater reuse system (The diagram and information in this figure is reproduced from the Plumbing Industry Commission of

Victoria’s Technical Solutions brochure. At the time of writing, the brochure is accessible from the Commission’s <website www.pic.vic.gov.au>.)




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3.3 Combined allotment drainage In combined allotment drainage, collection is as for the conventional system, but the discharge is either into a collective drain on a neighbour’s property, or access to the legal point of discharge is via a drain through an easement on the adjoining property.

Figure 8 – A combined allotment drainage system




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3.4 Pumped systems With a pumped system, stormwater is collected on site in a large pit or pump well. A pumping system discharges the collected water by a ‘rising main’ to a legal point of discharge. These systems are generally only permitted for domestic installations.

Figure 9 – A collector for a pumped drainage system. (Courtesy of Everlevel Drainage Systems)




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3.5 Charged systems Roof water in a charged system is collected and discharged to the legal point of discharge by syphoning. Surface water is disposed of on site by transpiration trenches or other means.

Figure 10 – A charged drainage system




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Figure 11 – Detail from plans for a charged drainage system




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3.6 Aquifer storage Aquifer storage refers to a system where storm water is collected and returned to the underground watertable. Currently, such systems are mostly used for irrigation but the increasing problem of acute water shortages is bringing forth great ideas for suburbs to collect the water, pre-treat it and return it to the aquifer.

Figure 12 – Aquifer storage and recovery of stormwater

3.7 On site stormwater detention This is becoming an area of development that local councils and water authorities use to delay the inflow of the peak runoff from a property to a flow rate that the receiving system can accommodate. Further detailed information about on site stormwater detention can be obtained from the Upper Parramatta River Catchment Trust’s booklet entitled Onsite stormwater detention handbook, located on their website <www.uprct.nsw.gov.au>. The following website also provides a good overview on this topic including necessary methods of calculation: <www.masterplumbers.com/plumbviews/2000/ stormwater.asp>.




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3.8 On site absorption With on site absorption, stormwater is collected and disposed of on site. The actual method of disposal varies. The following figures show the onsite absorption (trench) method of stormwater drainage.

Figure 13a – Typical detail of dispersal trench sediment control and level spreader

Figure 13b – View of method of installation of trench dome and gravel backfill

(Sourced from The City Of Ryde (NSW) Charged Stormwater Drainage Systems – Design Guide. Accessed from <www.ryde.nsw.gov.au>.)




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Figure 14 – The onsite absorption (soak well) method of stormwater drainage

(Sourced from The City Of Ryde (NSW) Charged Stormwater Drainage Systems – Design Guide. Accessed from <www.ryde.nsw.gov.au>.)




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4. Identifying system requirements

Recognising system requirements will form the core of your planning. You will need accurate information. You will also need to give clear written and oral guidelines to ensure the work is carried out correctly.

You will need to check plans, specifications, relevant regulations and standards. You will need to identify stormwater catchment and flow requirements and determine the appropriate size(s) for all piping, as well as finding out the stormwater overflow location. You might also need to determine the right size for retention pits, silt-flotation arrestor pits and/or rainwater tanks.

You must be sure that the system you design will meet the stormwater collection and/or disposal needs of the project.

4.1 Plans/specifications Before system designs can be developed you will need the surveyor’s plans and building plans. Interpreting plans and specifications to plan, size and document the layout of a surface and subsoil stormwater drainage system requires several judgments:

• Do you need to incorporate downpipes, pits, tanks and overflow discharge?

• Where does the system terminate and connect with the external stormwater drainage network? Further specifications may include provision for stormwater drains, easements, an on site storage tank, disposal pits, gutters and a subsoil disposal system.

• Is the stormwater displacement system gravity, pumped and/or displacement operated?

• Is the pipework suitable for the ground conditions? Soil test results may be needed, ie anchor blocks may be required.

• Will compaction testing be required?

Note

Don’t forget you will need to confirm all information and specifications you obtain. This will often involve a site visit.




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4.2 Regulations and standards As with any work affecting public infrastructure, you will need to consider any regulations and standards that affect what you can do in planning the size and layout of a stormwater drainage system. See the earlier section on the relevant standards and codes for stormwater drainage for detailed information. As discussed earlier, OH&S regulations will apply to protect the safety of all workers.

Environmental guidelines are provided to cover water quality management. Each state and territory has a branch of the Environmental Protection Authority (EPA) and they are uniform in the protection of the environment. In Victoria for example, the EPA administers environmental matters including waste management, stormwater protection and clean up. The EPA in South Australia has collaborated with CSIRO Land and Water and Australian Groundwater Technologies to produce a draft code of practice for Aquifer Storage and the recovery of surface water. Go to <www.epa.sa.gov.au> for further information on this code.

You will need to check your state or territory authority’s requirements, as well as the local government/council regulations for the area where your project is located. You will need to clarify requirements with the municipal officer in charge.

Local authority regulations

The starting point for determining what you can do in designing a stormwater system is to check requirements with the local authority, as these requirements differ from location to location. When checking local requirements for a job, note the name of the officer you deal with and continue to deal with that same person throughout the job.

Developments create huge areas of impervious surfaces (where previously water falling on those areas would have been ‘soaked up’). Developments also create collection points that channel large volumes of water into areas managed by authorities who often construct retarding basins to slow the flow of water and restrict the possibility of local flooding until the water can reach its normal discharge point (eg, a river).

Given the problems arising from soil composition in some areas (eg, areas with sandy loam or pervious rock formations), authorities now often stipulate that stormwater must be treated/dealt with on the allotment.




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For example, in the City of Ryde (in New South Wales), where the topography suits the installation of charged systems for roof water, surface water is treated on the allotment.

The City of Nedlands (in Western Australia) requires all stormwater to be handled on site.

All councils/authorities require drainage plans to be submitted with the building plans for approval. Your role might be as a consultant to the architect or you might be called upon to design and draw drainage plans yourself. However, authorities/councils are increasingly requiring plans to be certified by a person qualified to carry out that task (a plumber or architect, licensed for the task).

Note

Given a plumber’s valuable knowledge, plumbers today are playing a bigger role in development planning than in the past. When it comes to installing a system, if you had no part in designing or laying it out, you need to know how to check that what you are asked to install matches the plan, or more importantly complies with the standards. Remember: it’s your signature on the compliance form.

Once you have clearly established what the local authority requires (in writing or from a general guide the authority produces), you can commence planning. This may include finding out: • Where is the legal point of discharge to be? • What type of drainage system is required?

• What inspections will be required? • What information is required on plans? • What fee will be charged for connection points, etc?

Generally, when you personally approach an authority they will photocopy a plan of the area’s subdivision that shows allotments, easements and height datum.




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5. Designing the system

Am I familiar with the pipe system selected for the job? If you are designing a stormwater drainage system and you cannot confidently answer ‘yes’ to the above question, get contact details from your supplier for the representative of the product you will use. The representative should provide you with product advice and information, referring you to other similar projects and discussing the generally accepted trade practices of installation. This is particularly so with OH&S issues in heavy pipe and deep installations.

5.1 Sizing the layout

Remember

The relevant standards give you guidance and details of acceptable methods for carrying out your tasks. If you don’t know, look it up.

Design considerations

As discussed earlier (see section 1.8), there are two methods of design for surface drainage systems under AS/NZS 3500.3.2: the nominal method and the general method. Which one you use will depend largely on the size of the allotment.

The summary of design considerations for layout (below) and the example that follows are essentially drawn from the Plumbing Industry Commission of Victoria’s Technical Solutions brochures (go to <www.pic.vic.gov.au>). The brochures give a simple explanation of AS/NZS 3500.3.2 Roofing and stormwater calculations and layouts.




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Relevant considerations are as follows.

Minimum required pipe diameter (clause 7.3.4, page 75) • For single dwellings in rural and urban allotments of areas

less than 1,000 m2 = DN90. • For other properties downstream of a stormwater or inlet

pit = the greater of: − the diameter of the largest pipe entering the pit, or − DN 150.

• The exception to this is at the footpath crossing (see clause 8.6.1.2 (c), page 82) and Figure 8.1 from the Standard (reproduced below as figure 15).

Figure 15 – A typical system design drawing (Sourced from Figure 8.1 from AS/NZS 3500.3.2 Roofing and stormwater

calculations and layout)

System layout (clause 5.3m page 53 and see figure K1 reproduced below)

Three important design requirements for ‘Surface Drainage Systems’ are: • the allowance for possible stormwater flows from adjacent

properties • prevention of water ponding against buildings • the separation of stormwater drainage from the sanitary

drainage system.




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Figure 16 – Typical stormwater drainage installation plan Note that in the above graphic ‘Pit B’ is a silt arrestor.

(Sourced from Figure K1 from AS/NZS 3500.3.2 Roofing and stormwater calculations and layout).




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Solution to the design issues raised in Figure 16

1. The layout should comply with clause 5.3 so that the overland flow path is directed away from the building.

2. The stormwater drains are sized using clause 7.3.4 (page 75 of the Standard):

(a) Between a downpipe outlet and a stormwater or inlet pit = DN90.

(b) Between the stormwater pits A & B = DN 150.

(c) Between pit B and the street kerb = two DN 100 or less.

3. Minimum cover (from Table 7.1, page 72 of the Standard):

(a) Under paved driveway within the property = 75 mm below underside of the paving. Elsewhere = 100 mm.

(b) Under the paved footpath outside the property = 50 mm below the underside of the paving.

4. Minimum gradient (from Table 7.2, page 75 of the Standard) for DN90, DN100 and DN150 is 1:100.

Stormwater pits A and B on the plan are sized from Table 8.2, page 82 of the Standard. They are 450 mm x 450 mm with a minimum fall across each pit of 20 mm. (See also the Standard’s Figure 8.4(a), page 84.)




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Activity 3

Describe the procedures you would follow and the materials you would use to connect the stormwater drain from the building line of a property.

The concrete footpath outside the property is 2 metres wide and there is a nature strip 3 metres wide to the kerb. For this exercise, you should assume 100 mm of cover through the nature strip.




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5.2 Drawing the layout We have reached the stage where we know what type of system to install. Now we must draw up plans, make notes and calculations (also referred to as computations), design a system and draw up the layout.

What is a ‘layout’?

The layout is ‘the whole part of the drainage system’ as drawn on a plan.

The ‘whole part’ includes: • the line of drainage • composition of pipe and size • falls for drain and inspection openings • pits and grates

• topography contours of the land • heights of finished surfaces • floor heights at entrances to habitable areas • the scale of the drawing.

Key considerations

In your planning, you will need to make sure of the following: • the system layout is in accordance with relevant

plans/specifications, standards and workplace procedures

• the stormwater disposal system is specified in accordance with job requirements

• the materials required are specified (and optimised in accordance with standards) from the proposed design

• plans are recorded in accordance with regulatory authorities’ workplace requirements.




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Note

An authority/council official looking at the plans you present should be able to tell by your drawing that you have an understanding of stormwater drainage and the regulations thereof. They will have few questions if you have carried out your work in accordance with good trade practice and the relevant standards.

The layout process step by step

The layout process is summarised in the following section. Work through this process with your trainer/instructor/supervisor to ensure you understand each step in the process. Your final assessment for this unit will require you to complete this process by yourself. • Obtain a copy of the building plan showing the outline of

the building(s) on the property with the site boundaries drawn in.

• Ensure that north is indicated on the plan. • Visit the site to obtain levels and establish where the datum

will be. • If not indicated on the plan, draw in all impervious paths

and drives, with grated pits if there are any. Note the type of grated pit, ie heavy duty, light duty, wheelchair friendly.

• Mark on the plan all the downpipes. • Indicate any subsurface collection drains and where they

connect to the system. • Consider procedures for flooding. • From the legal point of discharge on the plan, draw a line

showing where you would expect to lay the drain to the furthest connection point (downpipe or grated pit). If needed, you can have two lines of drainage around the building.

• Indicate on the lines of drainage the size and composition of the pipes.

• Draw in the branch connections from downpipes into the drain or pits.

• Indicate by a thin line the contours of the land and the RL heights.

• Show the finished heights of impervious surfaces and pits.




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• Mark the sill height of any opening into the building(s). • If the project is large you will have to indicate the type of

pits required. Also indicate the inlet and outlet reduced levels.

• Any special features in the layout (pump pits, soakage pits, construction of these, etc) will need to be drawn up separately and attached to the drawings.

• For pumps, the type and method of control for float levels will need to be stated on another document attached to the plans.

• Show how to put large projects into table format with all relevant information.

There are enough examples in this resource or on the Internet to guide you as to the standard of good trade practice against which you can measure your plan. Alternatively, before lodging your application discuss your plan with a building consultant, clerk of works or the local authority if you have any doubts.

Activity 4

Draw up and plan the layout for a stormwater drainage system for a house on an urban allotment not more than 1,000 sqm. The legal point of discharge will be to the kerbing of the road at the front of the property.

Show the method used for overflow protection on an eaves gutter with the size of the gutter shown.

Create a ‘reference table’, setting out in chronological order your sources of information.

Discuss your response with your trainer/instructor/supervisor.




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6. Restoring the work area

Your plans to size and layout a stormwater drainage system must include steps that restore the workplace. If your planning site is different from the drainage system worksite, there will be two workplaces to restore.

6.1 Restoring the worksite To restore a work area, you need to plan the following: • The workplace is restored according to the workplace

procedure. The presetnation of the site when you hand a project to a client after you have finished is also important. This is part of the overall way in which you market yourself as a professional businessperson. − A poorly presented site may show deep ruts where

the excavator has been, a tree with bark scraped off its trunk, chipped bricks on the side of the house.

− A well presented site may show the site neat and level, all excess materials removed, a clean ‘planning site’ or office, all project papers removed to your main office, collated and stored in a file.

• Tools and equipment used in the process are cleaned and maintained and left in accordance with workplace procedures.

• Documentation, including work backup, is completed in accordance with workplace requirements.

The steps needed to complete the task are the same for both sites, so careful planning in earlier stages and attention to detail along the way will make planning this task easier.

For example: • If you are too busy to watch equipment being moved

around the site, then designate someone to be responsible for these operations so that surfaces and equipment are not damaged.

• Make sure any backfilling meets the requirements of AS/NZS 3500 .3.2 clause 7.2.13 page 74 (see also figure 7.1 on page 69 of the Standard). You should see that as much top soil as possible ends on top of the excavation and that you have consolidated the excavation.




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• Continual rain makes for a difficult job and councils are

cracking down on mud on footpaths and roads. If you are occupied elsewhere designate someone to ensure that roads and footpaths are clean of debris from your work at all times. You may also prevent silt and debris entering the stormwater by using a drain blocker. Ensure excavations outside the property are secured at night and that excavations are reinstated professionally.

6.2 Maintenance and storage of tools and equipment All tools need attention at the end of any plumbing project: • Maintain a site register that records all your tools and

equipment. Check them off as they are stored away to make sure none are lost.

• Lasers and all levelling equipment need cleaning and checking before storing in safe secure positions in your shed or other storage place.

• Check all metal surfaces of shovels, picks and concrete trowels. Before they are stored, all dirt and concrete should be cleaned off and the surface coated with a film of oil.

• Check wheelbarrow tyres and clean the inside of the barrow.

• Wooden handles of shovels, picks, brooms, etc need checking for smoothness of surface.

• Check leads of portable electric equipment for soundness. Make sure chuck keys are with each drill and points for the jackhammers are sound.

These are all good ‘housekeeping’ practices so you can load up for the next job or emergency with confidence, knowing that all you have to concern yourself with is the job you are heading to.

Don’t forget to clean the equipment stored in the ‘site office’ (camera, fax machine, lights, phones etc) and make sure it is working properly ready for installing on another site or storing.




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Activity 5

Read the final assessment activities at the end of this resource. Choose three drainage tools or pieces of equipment that you would use for one of these tasks.

Describe the maintenance and storage requirements for each piece.

Worksite tool Maintenance and storage requirements




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7. Documentation

Completing and storing all project documentation is a vital step in finalising your plans. You need to ensure that workplace procedures have been followed and legislative and statutory requirements are documented in the correct way. You will find that local councils, authorities and other clients will have differing requirements for documentation. It si your responsibility to determine in advance the documentation that is expected from you and then plan to provide it.

7.1 Domestic and commercial documentation requirements

Domestic

On a domestic project the plumber is required to sign and lodge a certificate of compliance for the work carried out. However, it is good practice to also complete and provide the local authority or council with a plan of the work as executed (an ‘as laid’ plan) together with the building plans for future reference. Domestic projects may also require an agreement be draw up between the plumber and other parties that may be affected by your work, eg property neighbours. You should address legal agreements in the unit BSBSBM401A Establish business and legal requirements. Ask your trainer/instructor/supervisor for more information on legal agreements.

Commercial

Commercial projects require hydraulic calculations of the system certified by a hydraulic mechanical engineer who is a registered building practitioner. The plumber must also complete and submit an as laid plan and sign and lodge a certificate of compliance. these document must be handed to the builder by the plumber to ensure payment for the work. Ultimately all documentation is then passed to the building surveyor who signs off on the project.




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7.2 Delays in documentation It is important to note that the finalising documentation can be held up in many ways. It is a good idea to be aware of these possible delays and plan to avoid them when you can. You may need to allow additional time in your project plan as a result. Common delays include the following:

• waiting for a written report from a consultant • a neighbour of the property hasn’t released an agreement

for you to access their property • approval of the works from the authorising body is delayed • you need clearance of external works from the local

authority • you’re waiting on submission or finalisation of an

insurance claim • the head contractor/builder hasn’t forwarded withholding

documentation.

Sending documents to authorities and ensuring they receive them is important in minimising delays for approvals. They can be transferred by email, registered mail or hand delivered by you or someone responsible.

7.3 Receipt of documents When hand delivering documentation always note in your diary the date, time and to whom you give the document. Alternatively, create a receipt that notes the document received and the day/date/time and make sure the person receiving the document signs and prints their name on the receipt. All this ensures you are not held to account for delays and cost overruns. You have carried out your obligations for your client.

To ensure a document is a ‘legal document’, it must be signed, witnessed and dated:

• your quotation becomes legal when it is accepted, signed and dated by the client and returned to you

• the contract, if needed, is also legal when it is signed, dated and witnessed.




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Requirements for smaller/larger sites

Documentation requirements often depend on how big the project is. Large commercial sites have well established site offices and a chain of command something like the following: • site manager • clerk of works, mainly involved with records • supervisor • foreman • gate guard.

Smaller development sites are usually under the control of a site foreman who is your first point of contact in obtaining access, coordinating procedures and required documents.

On the smallest sites the builder or developer is generally the person you deal with directly.

7.4 Document security If you maintain office equipment on site, it is best if only you have the password or key to operate it. Given the nature of worksites and more particularly human nature, there is always a ‘stickybeak’ wanting to know your business.

Secure the ‘office’ wherever it is. Keep all papers, plans and other project documents in a lockable cabinet. If you use the onsite computer to transfer money for payments to contractors and workers, only you should have the password.




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Activity 6

People in general do not like confrontation. We like to think that what someone says they will do, they do and in a perfect world that would happen. When disputes arise a solicitor will always ask you: what was the agreement? If there is no proper agreement often that’s when the trouble begins.

In this activity you are required to draw up an agreement to present to the owner of the property next door to the property you have been engaged to work on. The agreement is for their approval to allow you access onto their property and to carry out certain tasks that are necessary in installing the stormwater drainage. The agreement will list the activities you will undertake on the neighbour’s property.

Draw up an agreement and submit it to your trainer/instructor/ supervisor for discussion.




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Final assessment activities

To complete the assessment in this unit you are required to as a minimum, plan, size and document the layout details of a surface and subsoil stormwater drainage system for: • a residential unit development of at least five two-storey (Class 1)

units AND • a commercial (Class 5) building,

which includes drainage to the point of connection to the external stormwater drainage network (or legal point of discharge) ensuring: • correct identification of details of the plan • correct selection and use of appropriate processes, tools and

equipment • completion of all work to specification • compliance with regulations, standards and organsiational quality

procedures and processes.

The building or development may be either a new one or one that is already existing.

Building classes

For your reference the following information has been provided on building classes.

Class 1 refers to one or more buildings which together form: • � Class 1a: a single dwelling that is:

− a detached house; or − one of a group of two or more attached dwellings, each being in a

building separated by a fire-resisting wall (including a row house, town house or villa unit).

• � Class 1b: a boarding house, guesthouse, hostel or the like, where total floor area over all floors is not more than 300 m2 measured over its enclosing walls and in which no more than 12 people would reside.

• � Class 5 is an office building used for professional or commercial purposes, excluding buildings of Class 6, 7, 8, or 9.

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