hydraulics design guidelines

DDRRAAFFTT DDEESSIIGGNN GGUUIIDDEE LLIINNEESS PPLLUUMMBBIINNGG

%�� PLUMBING�

1. INTRODUCTION

This section establishes the general design guidelines to be adopted for the

Plumbing design of Hotels, Residential Buildings, Office Buildings, Shopping and

Retails Centres projects and describes the various systems that shall be

incorporated into the facilities design.

2. CODES AND REGULATIONS

The following standards are accepted for the design of PLUMBING provided that

necessary corrections and provisions are made to suit DEWA and all requirements

related to other local codes.

CIBSE Chartered Institution of Building services Engineers

UPC Uniform Plumbing Code

NPC National Plumbing Code

BS British Standard

3. DESIGN PARAMETERS

3.1 Rainwater

Rainwater run-off shall be based on a rainfall rate of 100 mm per hour. Pipes shall

be sized and laid at suitable slopes to maintain a self cleaning velocity of at least 0.6

m per second when flowing full.

3.2 Sanitary Drainage

Sanitary drainage design shall be based on the fixture unit method. The weight in

fixture units for various fixtures shall be as tabulated here below in Table-1 in

accordance with National Plumbing Code Handbook.


Table-1

Fixture Type Fixture Units

Water closet – Flush tank 4

Water closet – Flush valve 8

Lavatory – Private 1

Lavatory – Public 2

Urinal – Flush valve 4

Bathtub 2

Bidet 3

Shower – Private 2

Shower – Public 3

Drinking fountain ½

Floor drain 1

Mop sink 3

Kitchen sink 3

Dishwasher 2

¾� Bathroom group consisting of water closet, lavatory and bath-tub or shower

tray shall have 6 fixture unit (flush tank) or 8 fixture unit (flush valve)

¾� The determination of demand and usage shall follow the recommendations of

the National Plumbing Code Handbook.

¾� Pipes are to be sized and laid at suitable slopes to maintain a self-cleansing

velocity of at least 0.6 m/s when flowing full. Slope of pipes inside the building

is not to be less than 2%.

3.3 Domestic Cold Water

¾� The objective in designing the water supply system is to insure an adequate

water supply at adequate pressure to all fixtures and equipment at all times

and to achieve the most economical sizing of the piping.

¾� Design for cold water pipes shall be based upon diversified load for fixtures

used intermittently on the system.


Pipe sizes shall be determined by the fixture unit method, where one fixture unit is

equal to 0.47 liters per second. The weight in fixture units for various fixtures shall be

as tabulated here below in Table-2 in accordance with NPC.

Table-2

Fixture Type Fixture Units

Water closet – Flush tank 5

Water closet – Public - Flush valve 10

Water closet – Private - Flush valve 6

Lavatory – Private 1

Lavatory – Public 2

Urinal – Flush tank 3

Urinal – Flush valve 10

Shower head - Public 4

Shower head - Private 2

Drinking fountain ½

Mop sink 3

Kitchen sink 4

Dishwasher 4

Garbage disposal 3

Water outlet 1

Hose bib 2


3.3.1 Preliminary Estimate of Cold Water Demand

Determination of water demand shall follow the recommendations of the

National Plumbing Code Handbook. Table-3 shall be used to give a

preliminary estimate of the domestic daily water demand and pumping

capability:

Table-3

Building Type Estimated Occupancy

Water Demand Liter/day/person

Usage

Hours 1

Demand Factor 2

Hotels 1.75 P/Room 492 11 3.0

Office Buildings 10 P/100 m2 75 8 to 9 2.0 to 2.5

Office Buildings (With Restaurant)

10 P/100 m2 95 8 to 9 2.0 to 2.5

Residential Building

1.75 P/Bed Room 300 to 380 15 2.0 to 3.0

6 P/Parking space 4.8 Shopping

Center 3 4 Liter/m2 gross area/day

10 2.0

Note: The above figures do not include demands for any HVAC requirements

(if any).

3.4 Domestic Hot Water

¾� The hot water demand in fixture units (based on 60 deg C) for the different

types of buildings shall be based on the hot water demand for fixture and

storage factors obtained from table 1 of chapter 45 of the application hand

book of ASHRAE.

1 Average flow rate = Average flow per day ÷ Usage hours 2 Average flow per day = Peak flow/day ÷ Demand factor 3Incase of multi-purpose building (retails + offices), also office demand rates shall be used.


¾� Sizing of Service Water Heating Systems and Equipment shall be determined

in accordance with manufacturers’ published sizing guidelines.

¾� All water heating equipment, hot water supply boilers used solely for heating

potable, pool heaters, and hot water storage tanks shall meet the criteria

listed in table 7.2.2 of the ASHRAE Standard 90.1-1999. Where multiple

criteria are listed, all criteria shall be met.

¾� Temperature controlling means shall be provided to limit the maximum

temperature of water delivered from lavatory faucets in public facilities

restrooms to 43 deg. C.


Preliminary Estimate of Hot Water Demand

The followings give a guide to a preliminary estimation of hot water demand.

In this regards; two methods may be adopted by consultant, the first is the

fixture unit method, while the second is the daily demand method.

3.4.1.1 Fixture Unit Method:

The hot water demand per fixture for various types of buildings in Liter per

hour per fixture can be determined from table-4 below:

Table-4

Fixture Type Hotel Office

Building

Residential

Tower

Shopping

Center

Basins, private lavatory 7.5 7.5 7.5 7.5

Basins, public lavatory 30.0 23.0 - 23.0

Bathtubs 76.0 - 76 76.0

Dishwashers4 190-760 - 57.0 -

Foot basins 11.5 - 11.5 -

Kitchen sink 114.0 76.0 38.0 76.0

Laundry, stationary tubs 76.0 - 76 -

Pantry sink 38.0 38.0 19.0 38.0

Showers 75 114.0 114.0 114.0

Slop sink 30 76.0 57.0 76.0

Circular wash sink 76.0 76.0 - -

Semi-circular wash sink 38.0 38.0 - -

4 Dishwasher requirements should be taken from table or from manufacturers data for the models to be used, if this is known.


Fixture Type Hotel Office

Building

Residential

Tower

Shopping

Center

Demand factor 0.25 0.30 0.30 0.3

Storage capacity factor 5 0.80 2.00 0.70 0.9

3.4.1.2 Daily “Usage Method:

In this method, the estimated hot water demand characteristics for various

types of buildings can be evaluated from table-5 below:

Table-5

Type of Building Hot Water Required

per Person 6

Max.

Hourly

Demand

in Relation

to Day’s

Use

Duration

of Peak

Load

Hours

Storage

Capacity

in Relation

to Day’s

Use

Heating

Capacity

in Relation

to Day’s

Use

Residential 7 8 75-150 Liter per day 1/7 4 1/5 1/7

Office 7.5–11.5 Liter per

day 1/5 2 1/5 1/6

Hotels 20 - 40 Liter per day 1/7 4 1/5 1/7

5 Ratio of storage tank capacity to probable maximum demand per hour. Storage capacity may be reduced where an unlimited supply of steam is available from a central steam system or large boiler plant. 6 At 140 ºF 7 Daily hot water requirements and demand characteristics vary with the type of hotel. The better class hotel has a relatively high daily consumption with a low peak load. The commercial hotel has a lower daily consumption but a high peak load. 8 The increasing use of dishwashers and laundry machines in residences and apartments requires additional allowance of 55 Liters per dishwasher and 150 Liters per laundry washer.


3.5 Chilled Drinking Water System

¾� Provide all drinking water outlets with chilled water at 10°C.

¾� Where drinking fountains are stacked in the same location and the equipment

space is reasonably adjacent, consider using central (or sub-central)

circulating chilled water systems as they will be economically feasible.

¾� In areas where drinking fountain locations are scattered or irregular, provide

local chilled water units.

¾� Build local chilled-water units either into the wall under the drinking fountain,

exposed in a closet behind the drinking fountain, into the bottom of the semi-

recessed drinking fountain, into the back of the surface mounted drinking

fountain, or use unit water coolers, as per the architect’s preference in each

location. The units built into the wall or exposed in a closet may also feed

drinking fountains on the floor above and/or below in the same location.

¾� All central and sub-central chilled-water systems should be circulating type

with all bronze pumps.

¾� Where more than one riser is required, the�circulation line can act as one of

the feed risers.

¾� All local chilled-water units should be air-cooled.

¾� The central chilled-water units should be air-cooled (whenever possible), air-

cooled with blower; air- and water-cooled, or water-cooled, as size, location,

and the requirements of the local authorities dictate.

3.6 Water Treatment

¾� Provide water treatment, where necessary, to furnish a piece of equipment

with water of the quality essential for its operation.

¾� Water treatment equipment should be of a type and size as required for the

duty that it has to perform.


3.7 Irrigation System

¾� Provide irrigation systems where requested by the owner and /or the architect.

¾� Determine from the architect the exact areas involved, and the type of

planting, i.e., grass, flowers, shrubbery, trees, etc., in each area.

¾� Provide the water supply to irrigation systems with approved backflow

preventers. Check the code for detailed local requirements.

¾� Various types of plant materials require varying amounts or water and

different types of heads, consequently a single zone of sprinklers should

not be used to accommodate two different types of plant material (e.g., turf

and shrub beds). Select the proper type of head for the growth it is to serve,

as recommended by the head manufacturer.

¾� Overlap of sprinkler patterns is required. Layouts of sprinklers where spray

patterns are tangent are incorrect. In laying out the system, the

manufacturer’s recommendations for spacing are to be followed; not the cri-

teria for spray radius. Radius criteria shall not to be used, since this figure

refers to effective radius in some catalogs and extreme radius in others.

¾� In areas which are confined by sidewalks, buildings, parking lots, etc., provide

180° heads at the edge of these areas which throw into the area to be

irrigated. Do not locate heads which could wet areas not intended to be

watered.

¾� Irrigation systems should be provided with automatic controllers to properly

time the watering of each section and to stagger the operation of the various

sections to minimize the required peak water demand (flow). Controllers

should be the heavy-duty type.

¾� Where available pressure is insufficient for the requirements of a properly

designed system, provide a booster pump. Booster pumps should be sized

on the estimated peak flow required and the pressure differential required to

obtain the required pressure at the farthest head.


¾� As watering is usually done in off hours, its demand normally is not added to

the peak domestic demand on the project.

¾� Coordinate with authority regarding the possible availability of grey water in

the project site vicinity.

4. DESIGN CONSIDERATIONS

4.1 Rainwater

¾� Rainwater Drainage shall be collected from the roof through roof drains and

rainwater riser pipes. From there, rainwater shall be discharged to storm

network. Rain water pipes are not to be connected to sewer lines. If storm

network is not available in the area then rainwater will directly above ground

level.

¾� The drainage of roofs and paved areas shall be according to BS. 6367

¾� For all air wells, access doors should be provided at the lower level of the

well.

¾� For project having large rain catchment’s areas, rain water scheme shall be

designed to BS. 6367 and DM approval.


¾� Sanitary drainage shall be designed on the one pipe system with proper

fixtures venting or on the two-pipe system where waste and soil drainage shall

be drained in two separate pipes, to the same inspection chamber, with

fixtures properly vented.

¾� As a general rule use one pipe system for buildings exceeding 6 floors above

grade level. Buildings lower than this to be either one pipe or two pipe

system.

¾� Waste from parking garages shall be separately discharged into oil

interceptors before being connected to the main sewer line.

¾� Waste from kitchen equipment shall drain into a grease interceptor before

discharging into the main sewer line.


�� Waste from Laundry equipment shall drain into a lint interceptor before

discharging into the main sewer line.�

¾� Access points should be carefully sited to allow the service entry for cleaning

and testing

¾� All vertical stacks shall be provided with rodding eyes at junctions on every

floor.

¾� All horizontal drainage pipes shall have rodding eyes at points of change of

direction in pipes as required for effective maintenance

¾� Rodding eyes shall be provided where more than one water closet is

connected to connect to a horizontal soil pipe.

¾� Rodding eye shall be provided where the distance between one WC and

stack or manhole is more than 5 meters.

¾� Connection from the appliances lines on any floor and the main pipe shall be

in vertical stakes only.

¾� For all bends that are at base of stacks, provide a 45 or 90 degrees long

radius type elbow.

¾� For buildings greater than 20 stories appliances located at ground Floor and

first floor shall not be connected to vertical stack discharging at ground level in

single stack system, provide separate ventilation for individual connections

from the WC, floor trap, sink, etc. Any horizontal pipe longer than 1.5 meters

from such fixtures shall be vented on the high side.

¾� The drainage pipes shall be made not to run through electric rooms or electric

sub-stations

¾� Direct connection of waste system from a floor trap to a floor trap shall not be

permitted.

¾� The manhole (MH) schedule shall be arranged in such a manner determining

the manhole invert level (IL), cover level (CL), depth and distance between

manholes shall be referenced from Dubai Municipality using Dubai Datum.


¾� The depth of first MH shall be at least 450 mm

¾� Slopes for horizontal runs shall be as follows: 1:60 for 100 mm, 1:90 for 150

mm and 1:120 for 200 mm pipe diameter.

¾� Acute angle connections shall not be allowed within junction manholes.

¾� At a MH, the tops of all sewers should be at the same level so that the pipes

of smaller diameter are not flooded when the bigger pipes are running full.

¾� Backdrop shall be provided when the level difference between incoming and

main sewer is considerable

¾� Distance between MH to MH shall not exceed 15 meters in villas and

buildings.

¾� Minimum requirement for manhole venting shall be the provision of vent pipe

to first and last manholes of drainage line. These vent pipes shall be 100 mm

below cover level.

¾� The location of any manhole shall be kept away from underground water tank

by a distance not less than the depth of the water tank.

¾� In basement, sand trap with PVC bucket shall be provided just before end

connection of car park drain to the sump pump pit and the ramp drain channel

¾� If a basement sump pump is for rain water collection only from basement,

connect one waste pipe from the nearest toilet. To the basement drainage line

to make it always wet. Sump pump service only the basement drain and

sewerage MH.

¾� Drainage for the swimming pools and backwash pumps shall be shown on

separate drainage layouts plan, and the drainage line shall be shown on the

relevant drainage plan.

¾� For swimming pools on the roof or upper floors provide separate 50 mm dia.

pipe (after providing regulating valve) to the ground floor manhole connection.

Connection to basement sump pump shall not be allowed


¾� Shop facilities in buildings shall have waste, soil and vent connection

provisions for future with approved grating as per DM details

¾� Window A/C shall be provided with GRP trays having drainage facility

¾� All A/C & balcony drains shall be connected to waste pipe system via the

nearest floor trap or waste stack.

¾� Communal and public toilets shall be furnished with Asian type WC in

proportion not less than 25% of total number of WC required in addition;

public building shall have provision for toilet facilities for disabled persons.

¾� All floor drain shall have minimum 75 mm deep seal.

¾� Floor drains shall be provided in all garbage rooms in all floors and pump

rooms and all garage rooms.

¾� All water supply pipes shall be installed at least 1.0 m away from the sewer

pipe line septic tank or soak away.

¾� Urinals shall be connected to soil pipes.

¾� Septic tank and soakaway shall be selected to DM details and shall be

according to BS 6297.

¾� The foundation level of the base of the soakaway shall be kept at least 1 m

above the winter water table.

¾� The floor area of the soakaway shall be determined according to the

percolation rate in accordance with appropriate test in the BS. 6297.

¾� Locations of septic tank and soakaway should be shown on setting out plans

and on a general foundation layout plans.

¾� Soakaway shall be placed at least 1000 mm away from the septic tank

¾� Septic tank & soak away shall be located at least 3 mt away from any footing

for a building or a boundary wall.


4.3 Domestic cold Water

¾� The water supply to the building, shall be obtained either from the main

network of municipality or from tanker supply in emergency cases.

¾� The water supply and distribution in the buildings shall be of the up-feed type

to all plumbing fixtures, hot water heaters, and make-up tanks.

¾� Water hammer arrestors shall be provided in cold water supply branches

serving flush valves fixtures.

4.3.1 Hotels

The domestic cold water system for Hotels shall consist of the following:

¾� One day storage tank, tank shall be two compartment. Tank may be

concrete or sectional insulated GRP panels.

¾� Booster pump sets; maximum pressure from booster pump shall not

exceed 7 bar. If system requires more pressures due to building

elevation, then two sets should be used. One set to serve lower zone

while the other to serve upper zones.

¾� Pressure at farthest point in the system shall not be less than 1 bar

incase of using flush tank system, and 2 bar incase of using flush valve

system.

¾� Pressure regulating valve stations shall be provided to control zone

pressure. Refer to domestic water system flow diagram attached SK-

PLM-01 & SK-PLM-02 for Up Feed & Down Feed systems.

¾� Water treatment system consists of micron type filter and chlorination

system. The chlorination system should be installed to disinfect water

in tanks. Micron filters to be installed just downstream of booster pump

units.

¾� Cooling system: a cooling system consists of heat exchanger; and fed

by cooling media; should be used. The heat exchanger shall be

provided with all means to be protected against cross contamination


from cooling media. cooling media could be chilled water from HVAC

system, or from separate refrigeration system. The tank cooling system

to be provided with a circulating pump to circulate tank water through

the heat exchanger. A leakage alarm system should be provided to

indicate any leakage between domestic water and cooling media.

¾� The water tank shall be located in basement/ground floors and may be

located on roof subject to architect approval. When tank is installed on

roof, one booster pump set should be provided to serve the top five

floors, while the other floors to be gravity served from the tank.

¾� Two tanks may be provided, one at Basement/Ground floor to be sized

for 2/3rd storage requirements, and another tank on the roof to be sized

for 1/3rd storage. A booster pump set shall be provided to serve the top

5 floors.

¾� Water softener system: to maintain proper softening of water required

for laundry, kitchen and boilers (if any), a water softener shall be

provided. The soft water should be stored in a separate tank and

boosted up and distributed to the required points of use.

4.3.2 High Rise Residential Buildings

Same as for Hotels, except that water softener tank might not be required.

4.3.3 Low/Medium rise Residential/Office Building/Retails

Same as for High rise, except that one booster set to serve one vertically

divided zone shall be provided.


¾� Domestic hot water shall be supplied to all fixtures requiring hot water facility

including public toilet lavatories.

¾� Hot water shall be re-circulated where length of hot water supply pipe from

heater to a served outlet exceeds 15 mt.


¾� Hot water shall be generated by using either individual electric water heater of

the storage type to be placed above F.C. in relevant toilet/kitchen or central

water heater (electric / fuel operated).

4.4.1 Hotels

¾� Central hot water facility shall be provided to serve guests, back of the

house, kitchen and laundry.

¾� The central hot water system shall consist of domestic hot water

generator (steam/electric/L.P Gas), and distribution supply network.

Hot water pump shall be provided to circulate water aiming at

maintaining a maximum 5 ºC temperature drop at the furthest outlet of

the system.

¾� The guest room and other areas hot water supply temperature, except

kitchen and laundry, shall be maintained at 60 ºC. Laundry and kitchen

supply to be maintained at 72 ºC.

¾� Either one hot water system shall be used to serve the two temperature

systems, or separate systems shall be used. Incase of one system to

be used, then this system shall be designed at 72 ºC supply

temperature with a branch to be blended with cold water to reach 60 ºC

to serve the lower temperature supply system.

¾� Each return line to be provided with isolating valve and a thermostatic

valve that only opens when temperature in the return line drops below

the required preset temperature.

¾� Hot water pressure zoning to match with domestic cold water zoning.

4.4.2 High Rise Residential Buildings

¾� To be either central system or individual heaters per bathroom/kitchen

or per apartment. Central system to be used where tenants are not to

be charged for domestic cold water.


¾� If using central system, it shall be as same as described in paragraph

4.4.1 for hotels.

¾� The individual system heaters may be located in void above false

ceiling or in the apartment laundry room.

4.4.3 High Rise Office Buildings

¾� Only individual heater per toilet/kitchen to be used.

4.4.4 Retail Malls

¾� Individual heaters to be provided for toilets.

¾� Central hot water similar to one described paragraph 4.4.1 to be used

for large kitchens/lockers within retail mall.

4.5 Chilled Drinking Water System

¾� The minimum number of drinking fountains (water coolers) required in a

building or area of a building is usually governed by code. Most codes today

also have requirements regarding drinking fountains for the handicapped.

¾� Drinking fountains for the handicapped must be projecting type, with

projection of at least 0,45 m and mounted 0,85 to 0,9 m above the floor.

¾� Cafeteria water coolers are usually provided� with push-back glass filling

faucets. Some times they are also provided with a bubbler.

¾� In up-feed risers, connection to the circulating line should be taken, where

possible, at the ceiling below the top branch.

¾� Provide filters on all central units. Provide a minimum of two (each ½ size) for

each system (with as many as required for larger systems) separately valve

each filter.

4.6 Water Treatment

¾� Water softeners shall be resin exchange units (usually with automatic

regeneration) complete with brine tanks, interconnecting piping, and all


required accessories and controls. Normally units are sized on the flow

requirements of the system or equipment served. However, where flow

requirements are high (as for laundry washers), it may be more practical to

base the size of the unit on the average requirements and provide a storage

tank to supply the peak flows.

¾� Hardness to be expressed in grains per gallon as calcium carbonate.

¾� Acceptable periods between regenerations depend on the operating schedule

of system or equipment being served. Minimum should be 1 day.

¾� If 100 percent continuous supply is required, multiple units must be provided

to maintain supply during regeneration of one of the units.

¾� Automatic regeneration can be actuated by the quantity of water used or by a

time clock.

¾� The type of filter used depends on the filtration job it has to do and the

required quality of the effluent.

¾� Filters may be sand, diatomite, cartridge, or carbon type as required by the

application.

4.7 Irrigation System

¾� Select special type heads for trees, shrubbery, strips, edges, etc.

¾� Try to use as many 360° heads as possible in a given system since the costs

for installation of full-circle and part-circle heads are approximately the same

while the area covered is much less. The use of an excessive number of part-

circle heads will thus result in a higher unit price per area sprinkled.

¾� If part-circle heads are used, check to see if the watering density is different

from the full-circle heads. If there is a substantial difference, the part-circle

heads should be valved on a separate zone to permit the varying of the time

cycle to avoid over-watering or under-watering. Varying densities with part-

circle heads may occur with any type of spray head.

¾� Sections should be fed as near the center as practical to minimize pipe sizes.


¾� When manual sectional valves are used, they should be located so that the

operator will not be wet by the spray, and they should be easily located.

¾� Each section (zone) should be pitched to and provided with an automatic

drain valve.

5. OUTLINE SPECIFICATION

Detailed specifications shall be prepared by consultant during design stages. The

following are just an outline of required specification.

5.1 Rainwater

¾� Rainwater piping inside the buildings shall be uPVC.

¾� Roof drains shall be cast iron with large sump and flange, removable non-

clogging dome or flush mounted strainer and flashing clamp device.


¾� All waste drain and vent pipes are proposed shall be no-hub cast iron uPVC

with mechanical coupling or uPVC.

¾� Inspection chambers shall be reinforced concrete and complete with cast iron

cover. Inspection chambers deeper than one meter shall be provided with

steps.

¾� European water closets shall be floor or wall mounted type with flush valve for

toilets of public nature and flush tank in private toilets.

¾� Lavatories shall be vitreous china wall hung/counter mounted/pedestal type

as shown on project plans with chrome plated faucets/mixers.

¾� Drinking fountains shall be wall hung with integral cooler and stainless steel

splash back.

¾� Kitchen sinks shall be stainless steel.

¾� Bathtubs and shower trays shall be steel with baked enamel finish and

provided with showerhead.


¾� All internal piping shall be uPVC to BS. 4514 except waste piping which shall

be to BS. 5255. All under ground piping shall be to BS. 4660.

¾� Any manhole located in garage, driveway or other traffic areas shall be

provided with heavy duty covers, manholes and access chambers shall be lay

out according to consultant’s scheme. Covers provided shall be suitable for

the loads they are subjected to, and in accordance with BS. 497.

¾� An inspection chamber / manhole / gully trap constructed in covered area

shall be dry type and provided with recessed double seal type cover.

¾� If inspection chambers / manholes are in agricultural land, manhole covers

should be raised 75 mm above the natural ground level.

¾� Flexible polyethylene drain pipes shall not be used for a/c condensed drain

piping.

¾� Vent pipes from manholes and vertical stacks shall be extended 2 meters

above the roof. The end of which shall be fitted with vent cowls.

5.3 Domestic Cold Water

¾� Water piping inside the buildings shall be copper up to toilet areas where

high-pressure cPVC shall be used.

¾� Plumbing fixtures shall be equipped with chromium-plated faucets/mixers.


¾� Hot water piping shall be copper up to toilets where CPVC pipes shall be use.

¾� Insulation for hot water piping shall be pre-moulded and bonded fibreglass

applied to all the system piping including re-circulation system piping (if used).

¾� Individual hot water heaters shall be electric vertical or horizontal storage type

complete with maintenance access, thermometer, relief valve and controls.

¾� Hot water circulation pump (if used) shall be single stage close coupled

centrifugal in-line type.


¾� Service water heating system shall be equipped with temperature controls

that allow for storage temperature adjustment from 49 deg. C or lower to a

maximum temperature compatible with the intended use or unless otherwise

the manufacturer’s installation instruction specify a higher minimum

thermostat setting to minimize condensation and resulting corrosion.

hydraulics design guidelines

Documents