The Mechanical Training Centre (MTC) is a vocational training centre run jointly by His Majesty's Government of Nepal and the Government of Switzerland through the Directorate for Technical and Vocational Education (Nepal) and Helvetas Nepal.

SKAT, Swiss Center, for Appropriate Technology, is a documentation centre and consultancy group which is engaged in promoting Appropriate Technology in the Third World. Its mail-order bookshop with more than 1200 publications in stock and its publishing help to fulfill this aim.

First Edition

1976

Second Edition

1979, expanded content

Third Edition

1982, slightly revised

Fourth edition

1988, revised and expanded, co-published
by MTC and SKAT

Authors

Andreas Bachmann & Heinz Waldvogel

Editor

MTC (Mechanical Training Centre, Balaju,

Kathmandu/Nepal)

Publishers

MTC, Balaju, Kathmandu/Nepal
SKAT, St. Gallen/Switzerland

Copyright

Material of this publication may be freely quoted, translated or otherwise used. Acknowledgement is requested.

Comments

Questions and comments are welcome at MTC

Distributors

in Nepal:
Mechanical Training Centre
P.O. Box 4897
Kathmandu/Nepal

outside Nepal:
SKAT, Varnbuelstrasse 14
CH- 9000 St. Gallen/Switzerland
and
KODIS, Wartstrasse 6
CH- 8400 Winterthur/Switzerland

ISBN

3 908001 12 9

2.100

REQUIREMENTS

Installations between the distribution pipes and the water consumer must fulfill the following requirements in order to maintain a pure and high quality water supply.

2.110

Hygienic requirements - The water must stay free of pollution or anything else harmful to health. Examples:

- Absorbing dirty substances,

Also to be avoided are:

- the heating of water from the pipes (sun, fire, etc.)

2.120

Technical requirements - The installation and all connected apparatus must be to adapted to the existing mains and flow pressure (from the distribution pipes) guarantee to guarantee an adequate quantity of water.

3.101

Main - means a pipe laid by the water authority for the purpose of giving a general supply of water but does not include a communication or service pipe.

3.102

Communication pipe - means that part of a service pipe which lies between the main and the boundary of the street in which the main is laid.

3.103

Consumer - means a person supplied with water by the water authority.

3.104

Meter - includes an appliance or device used to measure or ascertain amounts of water taken or used from the water authority's waterworks.

3.105

Service pipe - means any portion of any pipe or any fittings from the water authority's mains to any premises which conveys or is capable of conveying water under pressure.

3.106

Supply pipe - means any portion of any pipe which is not a communication pipe.

3.107

Storage tank - means any tank for containing water supplied by the water authority or by the consumer, other than a flushing tank or hot water tank.

3.108

Flushing tank- means a tank with a discharging apparatus for flushing a water closet, sink, urinal or drain.

3.109

Cylinder- means a cylindrical closed vessel capable of holding water under pressure.

3.110

Water fittings- includes pipes and parts to change direction, branches, etc., (other than mains) taps, cocks, valves, etc.

3.111.

Apparatus- includes water closets, wash basins, bath tubs, kitchen sinks, machines, tanks and other similar devices. Usually they have a drain for connection to the waste water system.

3.112

Stop cock - includes stop tap, stop valve, angle valve and any other device for stopping the flow of water in a line of pipes.

3.113

Ball cock - means flow operated valve for controlling the inflow of water to a tank.

3.114

Overflow pipe - means a pipe so fixed that the discharge of water may readily be seen.

3.115

Waterworks- includes all catchment areas, reservoirs, wells, boreholes., dams, weirs, tanks, cisterns, tunnels, filter beds, conduits, aqueducts, fountains, standposts, sluices, valves, hydrants, pumps, prime movers and all other structures or appliances used or constructed for the collection, storage, conveyance, supply, measurement or regulation of water, and which have been constructed by or on behalf of the water authority and are the property thereof or which shall hereafter be used or constructed by the water suthority.

3.116

Premises - includes dwellings, buildings, lands and leasements whether open or enclosed, and whether public or private.

3.117

Catchment area - means any surface of land or other area which collects rainfall for the purpose of the waterworks.

4.100

FUNDAMENTAL RULES

4.101

Continuous supply from the mains - the water authority will endeavour to maintain continous supply of potable water to consumers but will not be liable for compensation in respect of loss or damage caused by or attributable to any failure or disruption or supply.

4.102

Security - The quality of the water supplied must remain uncontaminated. And the installations made by the plumber must be carried out with greatest care, according to this manual.

4.103

Skill and supervision - Practical work should be done only by specially trained persons. To attain this manual's standard, the installation should be supervised during construction and in operating conditions.

4.104

Materials - all materials installed should be of good quality to guarantee proper, trouble-free function and long life for the installation.

4.105

Apparatus - The sanitary apparatus supplied must be of standard make and connected with the septic or sewer systems. Protection against the exit of the poisonous and bad smelling gases must be ensured by means of siphon or trap.

4.106

Existing installations - Should also conform to the rules of this manual. If safety is not guaranteed, repairs should be done immediately.

4.200

PROTECTION FROM DAMAGE FROM FROST

Every water fitting, whether inside or outside a building, should be placed so as to reduce the risk of damage by frost.

4.300

SUPPORT OF PIPES

Every pipe shall be properly supported and so arranged as to avoid air locks or reverberation.

4.400

PROTECTION AGAINST WATER HAMMER

Both in choice of apparatus and design of the installation, consideration should be given to the avoidance of water hammer.

4.410

Plug valves - should not be used, except for draining purposes.

4.420

Spring loaded flushing systems - (as for closets, urinals) should be avoided, instead cisterns should be utilized. If a spring loaded flushing system is necessary then it should be installed so that there is no possibility of a cross connection between the drinking water and the waste water system.

4.500

PROTECTION FROM DAMAGE FROM OTHER CAUSES

Every water fitting should be so placed as to be readily accessible for purposes of examination and repair.

4.510

Dissimilar metals - water fittings of unlike metals should not be used unless effective measures are taken to prevent deterioration.

4.600

DIRECT CONNECTION OF TOWN SUPPLY

With pipes from private water supplies is not allowed.

4.700

PREVENTION OF WATER POLLUTION

4.710

Principles

4.720

The entire installation has to be assembled so that there is no possibility of back siphonage or back-flow of foul water or sewage or any form of pollution to the installed water system.

4.730

Pipes are not to be laid through sewers, - etc: No pipe shall pass into or through any ashpit, manure pit, sewer drain, cesspool, trash chute or through any manhole.

4.740

Cross connections - from the drinking water with the waste water system are prohibited.

4.750

Waterworks have to be kept clean. It is not permissible to deposit any earth, material, liquid or any dead creature in such manner or place that it may be washed, fall or be carried into the waterworks. However, nothing in this section shall be analysed as prohibiting or restricting:

a) any method of cultivation of land which is in accordance with the principle of good husbandry; or

b) the reasonable use of oil or tar on any highway maintainable at the public expense, so long as all reasonable steps are taken for preventing the pollution of any part or any water of the waterworks.

4.800

APPROVED MANUFACTURE

All pipes and fittings which carry water supplied by the water authority must comply with their regulations and be of approved manufacture.

4.810

Costs of replacement - All water installations have to be of good quality. It is required that water is kept clean and is not contaminated in any way, also including through defective installation. Consumption has to be within reasonable limits and must be measured properly. Although water is supplied by the water authority, alteration or renewal of pipelines and fittings may be charged to the consumer.

4.820

Entry into premises - The water authority may enter into premises into which pipes have been laid for the supply of water:

a) to inspect any supply pipe

b) to regulate and repair any supply pipe or meter as circumstances may require

c) to ascertain consumption

4.900

DISTRIBUTION OF WATER FROM OTHER SOURCES

The concerned person should apply to the water authority for a licence if the water has to be supplied from under ground or from a river, lake or pond lying within the distribution area of the water authority.

However, a license may not be required for the under mentioned conditions which should be checked for approval with the concerned water authority:

a) If somebody wishes to take water supply of up to 5,000 liters (or the proper quantity approved by the water authority) for household purposes.

b) If some land owner wishes to take the water supply for cultivation of his own land from the nearest source attached to his land.

4.910

Responsibilities of waterworks - Waterworks are under the responsibility of the water authority for the following:

a) operation of waterworks

b) maintain the quality of water supply

c) grant permission to draw off, divert or take water from any stream or waters by which the waterworks are supplied, or

d) arrange to open or shut any valve, hydrant or stopcock belonging to the water authority

5.100

COMMUNICATION AND SERVICE PIPES (water authority)

All communication pipes at present existing or here-after constructed should vest in the water authority and the water authority should at it's own expense, carry out any necessary works of maintenance, repair or renewal of such pipes.

Figure

5.110

Provision and maintenance of fittings - The water authority may provide and sell or hire any water fittings and may install, repair or alter any water fitting, whether supplied by it or not and may provide any materials and do any work required in connection with the installation, repair or alteration of water fittings, making reasonable charge therefore.

5.120

Stopcocks on pipe lines - every pipe supplying water to a building shall be fitted with a stopcock adjacent to the water meter; near to the ground tank; or inside and as near as possible to the point where it enters the building.

5.130

Water authority regulations prohibit the installation of a suction pump directly into the main supply pipe lines.

Figure

5.200

SERVICE AND SUPPLY PIPES (Consumer)

5.210

Costs relating to supply pipes - The cost of constructing, altering or repairing all supply pipes shall be borne by the consumer.

5.220

Stand posts - No person should erect a standpost for conveying water (supplied by the water authority) for the occupants of more than one building or of separately occupied parts of a building unless the pipe is provided with a non-concussive self-closing tap.

5.230

Drinking troughs - Every pipe supplying water to a drinking trough or drinking bowl for animals and poultry should be fitted with an approved ball cock for controlling the inflow of water so as to prevent overflow.

5.240

Tap and stop cock pressure requirements - Every draw-off tap and every stop cock not of the ordinary screwdown pattern shall be capable of withstanding a hydraulic test pressure of at least 20 kgs/cm2 and shall be of approved manufacture.

5.250

Location of stop cock - every stop cock should be so placed that it can be readily operated by the means by which it is designed to be operated.

6.100

PRINCIPLES

The provision, size and the placement of all water meters, both for domestic and industrial premises should be approved by the water authority.

6.200

POSITION

A water meter should, in general, be installed inside the consumer's boundry wall in a secure and readily accessible position.

6.300

INSTALLATION

Water meters, in general, are to be supplied by the water authority. A stop cock should be fitted on the supply side of the meter and the meter itself should be

fitted between unions or flanges for easy replacement.

6.400

ACCURACY OF METERS

The accuracy of water meters has always to be maintained. No person is permitted to:

a) alter or cause or permit to be altered any supply pipe with intent to avoid the accurate measurement of water;

b) willfully or negligently interfer with or injure any meter;

c) dishonestly alter the index of any meter used by the water authority; or

Handling of water meters, including repairs and replacements, are under the rules and regulations of the water authority.

7.100

PRINCIPLES

7.110

Materials for storage tanks - Every storage tank should be watertight and of adequate strength and should be constructed of galvanized iron or steel, copper, ferro-cement, concrete or other approved materials, and should be provided with a cover of an approved pattern.

7.120

Protection from corrosion of storage tank - Every tank should be suitably protected from corrosion.

7.130

Capacity of storage tanks- Every storage tank should have a capacity of not less than 100 liters and if used for hot water systems of not less than 200 liters.

7.140

Placing of storage tanks - Every storage tank should be so placed and equipped that it can be readily inspected and cleansed, and not be liable to any contamination.

7.150

Storage tank support - Every storage tank should be adequately supported and suitably covered.

7.160

Every storage tank should be provided with a:

a) Manhole, having a diameter of at least 50 cm, the edge of which is at least 20 cm above the tank top. The manhole should be provided with a cover which can be securely fastened;

b) Device, for the control of the inflow of water, so designed as to prevent overflow (e.g. ball cock or electrical pump-switch);

c) Overflow, which should be of a larger diameter than the inlet pipe and be at least 2 cm below the inlet level;

d) Ventilation pipe;

e) Drain valve if possible

f) Stopcock, to be fitted to each draw-off pipe, as near to the storage tank as possible (on tanks exceeding 20 liters capacity).

7.170

Ball cocks

7.171

Every ball cock shall be securely and rigidly fixed to the tank it serves.

7.172

The ball cock should be fitted in such a position that:

a) It discharges at a level higher than the level of the overflow;

b) can easily be checked and repaired from the top, and without necessarily draining the water tank.

7.173

Every ball cock should be of approved manufacture and comply with the following requirements:

a) Working pressure of 15 kg/cm2 with every medium pressure valve of 10 kg/cm2 and every low pressure valve of 5 kg/cm2.

b) Every ball cock of the piston type should have a suitable washer of approved materials.

7.200

LOW LEVEL STORAGE TANKS

7.210

Principles

No storage tank should be buried or sunk in the ground unless there is sufficient space around for the purposes of maintenance and the detection of leaks. This shall not apply to a concrete tank designed and constructed to an approved standard.

When possible, tanks should be installed above ground level.

In the case of sunken tanks special precautions should be taken to avoid flooding. In particular, the manhole should be above any possible flood level.

Low level tanks should be secured with fastened manholes, having inlets with a control device (ball cock) and an overflow. Where possible, a drain-out system should be fitted which should include a drain cock or plug.

7.300

ROOF TANKS

7.310

Placement - Roof tanks shall be securely placed on top of the house installation, taking into account the structural requirements to carry the heavy weight. Tanks have to remain easily accessible for inspection and maintenance. They shall be placed on adequate battens, leaving gaps for air circulation beneath.

7.320

Tanks inside the building - roof tanks inside the building require a safety tray made of watertight design, having side walls of not less than 10 cm in height. Such trays need to be of greater surface area in order to securely collect overflowing water from the tank. A separate drain is required for the safety tray. Such tanks also require to be on battens leaving gaps for air circulation and prevention of condensed water accumulation.

7.330

The inlet requires a control device

a) A ball cock when connected directly to a pressurized system (town supply).

7.340

The supply outlet should be positioned 5 to 10 cm above the bottom of the tank.

7.350

A drain out should be provided and arranged so that there is no direct connection with the waste water system.

7.360

Roof tanks require an overflow, the diameter to be larger than that of the inflow. The level of the overflow to be at least 2 cm below the level of inlet.

7.400

PUMPS

7.410

For installations in buildings pumps are normally used to move the drinking water from the ground tank to the roof tank, i.e., where the pressure from the mains is insufficient.

7.420

Alternatively pressure boosters, with cylinder and pump could be used, where there is continuous electricity supply.

7.430

The most common type of centrifugal pump used in such small installations is of the “monobloc” type, powered by electricity.

7.440

Pumps and motors should be securely mounted on concrete blocks, preferably higher than the surrounding floor or ground level. Pumps should also be provided with a roofing, in order to protect the electric motor and it's connection from rain water.

7.450

Pumps, as other devices fitted to the pipeworks, should always remain easily accessible for maintenance, and always be fitted with flanges or unions for easy removal.

7.460

Pump connections. These can be divided in two groups:

a) Suction or inlet pipework

b) Delivery or discharge pipework

Further there are differences in:

c) Gravity-fed installation (= efficient and trouble-free) (Ref: table no 1/11)

d) Suction-fed installation (Ref: table No 1/12)

7.470

Suction pipe - This pipework should be kept as short as possible and have a gradual rise towards the pump (to avoid air locks in the suction line). Diameters of such suction pipework should be the same as of the pump inlet connection or preferably be of the next larger diameter.

It is suggested to install a tee-piece near to the entrance of the pump, fitted with a valve and a funnel to enable initial priming, when required.

7.471

Foot valve, strainer - Suction pipes require a foot valve. It maintains water in the suction line on completion of pumping, reducing the need to prime the pump when pumping is recommenced. A swing type valve is recommended. A strainer is often incorporated in this type of foot valve.

7.480

Delivery pipework. The diameter of such pipes should be the same as of the pump exit connection. The pipes should be fitted in a straight line and where bends are required use those with a long radius to minimize frictional losses.

Pipes should be arranged so that there is a gradual rise from the pumps towards to the roof tank to enable automatic air release at the highest point, i.e. at the tank inlet.

7.490

Adjacent to the pump a non-return valve is to be fitted. This valve prevents the water of the delivery pipe from draining back through the pump casing when the pump is turned off.

Non-return valves: A swing type valve is the most suitable, since it offers less restriction to the flow as compared to the under-and-over type.

7.500

DOUBLE-PUMP INSTALLATION

For larger buildings at least two pumps should be fitted, having the necessary bypass pipeworks and valves. These pumps should be run alternately, giving security for continuous water supply.

8.100

PRINCIPLES

The pipelines (pipes and connections) should be protected against corrosion.

8.200

PIPES IN THE GROUND/SOIL

Pipes, fittings and valves should be protected with an inert insulation.

Before the corrosion protector is applied to the pipes, all rust, tinder, dirt and all other impurities have to be removed.

The protection of pipes should be ensured by providing a suitable pipe cover.

Possibilities:

a) Steel pipes, galvanized pipes - galvanization is not sufficient as outer protection, it tends to be damaged during installation. Bitumen paint and a layer of hessian can protect the pipes.

b) Cast-Iron - in a very aggressive soil even cast-iron pipes have to be protected against corrosion. (clay soil, pipes in refill of building rubbish).

c) Plastic pipes need no protection against corrosion, but they should be well protected against mechanical destruction and if necessary should be laid in sand. No stone or rock should be used in the first stage of refilling.

8.300

PIPES IN BUILDINGS:

If the pipes are visible, galvanized pipes will be used. Copper and stainless steel need no additional protection.

8.310

Pipes in the walls (under plaster): galvanized steel pipes must be protected with an anti-rust paint and with a wrapping or bandage, which must remain completely dry.

9.100

MATERIALS

9.110

a) Laying in soils:

- welded or seamless steelpipes, galvanized, (called G.I. pipes)

- jointless steelpipes, internally coated

- cast-iron pipes (called G.I. pipes)

- H.D.Pe (only best quality and made specially for water pressure pipelines to be used).

- Ductile iron pipes

Prohibited:

- Plastic pipes as used in conduits for electrical installations.

- the use of lead pipes (poisonous)

9.120

b) Installation in buildings:

- welded or seamless steel pipes, galvanized (G.I. pipes)

- copper

Prohibited: lead pipes

9.200

PIPE CONNECTIONS

9.210

The pipe connections should be made in such a way that the strength of the pipe material should not be weakened connections as follows:

- Thread connections, welding connections

- hard soldering, compression joints

- screw socket connections

- connections with flanges and gaskets

- connections with sockets and lead.

9.220

Thread connections - fittings of good quality are necessary for thread connections with steel pipes (G.I. pipes).

9.230

The fittings have to be leak-proof. The thread must be cut exactly at to right angles all branch directions. They must also have full threads without much space. After cutting the pipes, the inside burr (spin) must be removed.

9.240

Thread cutting - lubrication oil of acceptable quality shall be used for thread cutters
(No old mobil oil!)

9.250

Thread joint - non-poisonous materials shall be used, such as hemp and joining paste (compound) or teflon tape. No putty: the use of putty is prohibited.

Cautions: Red and white lead jointing compounds should not be used in pipe joints for health reasons (white lead was very often used, but it is a health risk).

Connections with flanges - Flange connections shall be used for pipes of 2” diameter and above. Flanges are often also used on pumps and other machines. The flange surface shall be parallel.

Other pipe connections - Caulked socket connections (lead joints). Lead joints should contain, after finishing the connection, jute rope in 2/3 of the socket, and lead in 1/3 of the socket.

Before caulking the rope inside the sockets, ensure that the pipes are well pushed together into the sockets, so that the rope does not enter into the pipes. Also check that the ring-type joint has been properly centered (centric-placement).

The joint should be poured in one casting as fast as possible.

Nominal

Diameter

Approx. weight per meter in kg

Useful length of thread in mm

i.d.*

o.d.

1/2

16

21.3

1.2

13

3/4

21.6

26.9

1.5

15

1”

27.2

33.7

2.4

17

1 ¹/₄”

35.9

42.4

3.1

19

1 ¹/₂”

41.8

48.3

3.6

19

2”

53.0

60.3

5.0

24

2 ¹/₂”

68.8

76.1

6.5

27

3”

80.8

88.9

8.4

30

10.100

LAYING IN SOILS

Pipelines must be placed as deep in the ground as possible so that they do not get damaged through mechanical forces, e.g. traffic. The covering should be, if possible, at least 1 meter deep.

Pipelines underground should be installed on a rising alignment so that the pipeline can be drained and air be released from the water system.

If the soil is yielding, the pipes must be protected, e.g. cast iron pipes break easily through settlement of poorly consolidated soil.

Water pipelines must be at a higher level than the sewerage systems (waste water lines), so that leakage from foul water may never enter the drinking water system.

Cast iron pipes are vulnerable to any movement and must be protected by being surrounded with an elastic substance when passing through walls.

If there are valves outside the building, they must be protected, have a waterproof signboard, and be indicated with marker plates.

For pipelines laid in the ground: bends should be used in preference to elbows.

10.200

PIPELINES INSIDE THE BUILDING

10.210

Layout - The pipelines should be laid as straight as possible, and change of direction made by means of elbows with a small radius.

10.220

No bending - G.I. pipes must not be bent (by bending the galvanization may split off and cause corrosion).

10.230

Drainage - A drain valve must be installed at the lowest point of the whole installation.

10.240

Pipe closure - Pipe covers have to be made of pressure resistant and watertight materials, such as: metal, plastic or other suitable materials. A cover can be a plug, cap, blind flange, etc., however, other stoppings (as for example wooden plugs) are not permissible. Completed installations, but not connected inside pipelines, must be closed with such covers.

10.250

Building strength - The building must not be weakened through the installation of pipelines and other sanitary requirements, (slits, openings, cutting of reinforcement iron, etc.). Therefore, care must be taken to avoid weakening the structure when breaking holes. Particular care must be taken not to cut reinforcing material.

10.260

Exposed pipelines

10.261

Water pipelines must be installed beneath the electric installations, where possible. (Condensed water may cause danger to the electric installations).

10.262

Pipelines passing through floors exposed to high moisture (kitchens, bathrooms) must be protected by waterproofing fitted closely to the pipe (Ref: Table 1/8)

10.263

Pipes should be firmly fixed with clamps, pipe carriers or suspension fixtures. In general these should be spaced at 1.5 m intervals, but account should be taken of the diameter and weight of the pipe.

10.270

Concealed pipelines (under plaster)

10.271

G.I. pipes and fittings (in protective wrapping) may only be covered with non-corrosive material such as cement plaster.

10.272

Any water connection liable to leakage (e.g. union, flange connection, valve) should not be concealed.

10.273

Hot water pipes require special attention for reasons of expansion and contraction, and also for reduction of heat losses (insulation).

11.100

COLD WATER

11.110

Distribution lines: Each house should have at least two separate lines, each having a gate valve. They should be connected near to the water meter or adjacent to the roof tank. One line to be for the kitchens and the other for the bathrooms, so as to allow separate sections to be cut off without interrupting the supply to the other section.

11.111

Additionally, in low pressure systems, there may be another separate distribution line with a valve for the hot water system. Fitted also near to the roof tank or adjacent to the water meter.

11.120

Branch lines - Houses designed for more than one family, and apartments, as well as hotels, hospitals, laboratories, etc., require a separate service valve for each unit (e.g. per one bathroom in a hotel), so as to allow convenient repairs, without interrupting the others' water supply.

11.200

HOT WATER SYSTEMS

11.210

Hot water systems, in general, should be installed in the same way as cold water systems. However, more attention is required to the change of length through temperature variation (expansion, contraction), as well as for proper insulation.

11.211

Hot water systems are more liable to corrosion than cold water systems.

11.212

Hot water heaters should operate at temperatures of approx. 60° Centigrade, but not exceeding 70° C.

11.230

Domestic installations: The water is heated in water heaters (by electricity, gas, solar, etc.). They should be centrally positioned, so that the hot water is quickly available at the users' taps. These direct systems supply bath, kitchen sink, wash basin, etc. This system is commonly used in Nepal for domestic requirements and in hotels, hospitals, etc.

11.240

Centralized systems: Water is heated and stored centrally and distributed throughout the building by means of pipework with good insulation. In order to quickly receive hot water at the users' places these systems require constant circulation by means of a circulation pump, (or probably through thermosyphon, provided the hot tank is placed in the ground floor). These systems require much attention to good insulation to reduce heavy heat losses in the pipelines.

11.250

Hot water tanks should be positioned so that:

- the hot water reaches the taps within 20 to 30 seconds;

- they remain easily accessible for maintenance and repairs;

- heat loss is reduced, therefore tanks are fitted inside the building only.

11.260

Hot water taps should always be fitted in mixing arrangements, i.e. to have one spout outlet for both, cold and hot water. Such mixing taps require attention to guarantee proper function and safety to the house installation:

a) Hot water connections to mixing taps should always be on the left side (and with vertical mixers the hot tap below).

b) Mixing taps must always have one open outlet in order to avoid internal hot water circulation into the cold water line, i.e. without intervening valve between the mixing valve and the outlet.

Figure

Figure

c) For successful shower installations it is required that the pressure must be adequate. Note that telephonic showers have large losses in pressure and should be installed only where pressure is above 5 meters head, otherwise a metal pipe should be fitted.

11.300

HOT WATER TANK CONNECTIONS

11.310

Hot water tanks may be connected to the supply lines only if adequate security measures are taken into consideration (non-return valve, safety valve, pressure reducer, etc.). The source of energy (electricity, solar, gas, etc.), makes no difference for the above requirements.

11.320

A hot water tank must always remain filled with water; i.e. not to be drained when cold water pipelines are without water.

11.330

Pressure of supply line and limits of tank operation pressure are to be checked prior to installation. Where the pressure in the cold water line exceeds 30 kg/cm2, and where the heater is not designed to operate at high pressure, a pressure reducing valve or a separate feed tank (with ball valve) has to be fitted in the cold water system.

11.340

A stop valve must be fitted in the cold water line adjacent to the heater to allow it to be removed for repair without draining the entire line.

11.350

Inlet and supply connections to heaters must be fitted with unions, and the cold water inlet must lead to the bottom of the heater.

11.360

A drain branch should be fitted between the stop valve and the apparatus (or the non-return valve, if such is installed), which should be provided with a drain cock operated with an open-end spanner or a stop valve or plug. Note: drain outlets may not be connected directly to the waste water system.

11.370

Non return valve - A non-return valve is to be fitted in the cold water line, adjacent to the stop cock valve.

11.380

A safety valve is to be fitted between the non-return valve and the heater (and not having under any circumstances any stop valve fitted between!)

11.381

Safety valves should be provided with a drain outlet, which must not be connected directly to the waste water system.
Safety valves should release pressure if there is an increase in pressure of 0.5 to 1 kg/cm2 above normal working pressure in the line.

11.390

For smaller heaters up to 7 kW/hr one safety valve of 1/2” diameter is sufficient. Larger capacity heaters require larger safety valves (note: lever-arm safety devices are not permissible).

11.400

HOT WATER TANK CONNECTIONS TO ROOF TANKS

11.410

It is recommended to have separate cold water lines from the roof tank to each water heater. This system does not require a non-return valve (which often leaks and/or reduces an easy flow of water). The hot water tank will remain filled with water, even when the roof tank is empty (safety of electric heating element). A separate stop cock is required, adjacent to roof tank.

11.420

Over-pressure is to be released by means of a safety valve. Instead of a safety valve, a vent pipe can be fitted to allow excess pressure to escape. A vent pipe also acts as a anti-vacuum and so ensures an easy flow of hot water. This has its importance, especially in low pressure systems.

11.430

In buildings having more than two storeys or where it is not practical to provide separate water supply piping from the roof tank to each hot water tank, there must be fitted between the stop valve and the heater in a readily accessible position: a non-return valve and a safety valve between the non-return valve and the heater.

11.440

Hot water tanks must be fitted with unions, and have a drain branch in the cold water inlet pipeline. Drain outlets must never be connected directly to the waste water systems!

11.500

ECONOMICAL HOT WATER INSTALLATIONS

11.510

In order to achieve economical utilization of hot water systems great care is required at the planning phase. It is essential to reduce heat losses to the minimum. When installing hot water tanks and pipe-lines the following points should therefore be observed:

a) Use well-insulated hot water tanks only, having a minimum of 50 mm thickness (or preferably 75 mm) of good quality insulating material.

b) Where possible, keep the hot water tank inside the building, especially in areas where freezing can happen.

c) Keep the hot water supply pipes as short as possible, especially to the kitchen sink. The sink is used more frequently than other apparatus and a near-by water heater is therefore an energy-saving and economical solution.

When having a solar water heater system at a distance from the kitchen sink, an additional small water heater fitted near the sink could prove economical by using preheated water from the solar system.

d) Instead of using one pipeline of larger diameter it might be better to have several lines of smaller diameters, leading from the hot water tank to the various hot water taps.

e) Insulation of hot water pipes is required especially where the exit is directly from the top of the hot water tank. To reduce the heat losses at least the first vertical pipe and part of the horizontal pipe require an insulating cover (This situation often occurs with solar water heater installations).

11.600

SAFETY

11.610

Electric hot water tanks must be fitted properly to guarantee complete safety.

a) Installation away from direct water sprinkling: shower, bath tubs, rain, etc.

b) Electric connections (earth, fuse, switch, etc.) as per rules and regulations through specialized persons only.

c) Water heater not to be damaged when pipe system is without water supply. (Water tank always to remain filled with water - and draining possible only by opening of special valves).

Purpose

medium consumption/day

maximum consumption/day

Liter/person at 60-65 °C

Liter/person at 60-65 °C

modest domestic

20- 40

30- 60

comfortable standard

40- 60

60- 90

high standard

60-120

90-180

children hostel

40- 60

60- 80

hospital (town)

70-100

100-150

hostel (luxery)

upto 200

upto 300

Consumption

Quantity in ltrs.

Temperature °C

bathtub

150-200

40

shower (ca. 5-6 min.)

40-60
(20 - 30)

40

bidet (for 1 filling)

25

40

washbasin (1 filling)

6- 8

40

kitchen (1 filling)

25-30

50-60

dish washing machine

15-25

55

12.110

Each individual piece of apparatus in the installation must be controlled by it's own stop valve (angle valve, etc.). The connection between the stop valve and the apparatus should enable easy repair of the apparatus and valves, or easy removal for replacement.

12.120

Every draw off point (wash basin, closet, floor drain, etc.) must be connected to the waste water system with trapped outlets.

12.130

Open containers with direct connection to the drinking water system and without automatic inflow regulation must have the lower edge of the drinking water outlet to be at least 2 cm higher that the overflow, (Ref: Table: 1/7). If the inlet must be introduced under water level (fishbasin, swimming pool, etc.) a special interruption system must be introduced to obtain 2 cm space in order to prevent back-siphoning.

12.140

Closet/Urinal Flushing in principle, water closets and urinals shall be flushed by means of cisterns only. Where in special cases valves for direct flushing are fitted, it is absolutely essential that a back-flow prevention is included in the flushing pipe (e.g. vacuum breaker), to make any siphoning from the pan into the drinking water pipelines impossible. Note that such a flushing system requires pipes with large diameter, and could be troublesome when flushing in low-pressure systems.

12.150

No pipe other than flushing pipe leading from a flushing tank shall be connected so that it can deliver water to any water closet pan or urinal.

12.160

Volume of flush no flushing tank or other flushing apparatus serving a water closet pan shall give a flush of more than 10 liters (or of more than 5 liters per stall of a urinal).

12.170

Fixing of non-return valves these valves are fitted to prevent return flow of drinking water (i.e. opposite direction of supply). They are required with: hot water systems, pumps, foot valves, machines, thermo-regulated valves, pressure boosters, water treatment plants, etc. Note: direct connections with other mediums than drinking water are prohibited by any means. Direct connections are not permitted by use of non-return valves!

12.180

Connections of machines are to be made of high-pressure resitant flexible tubes, and preferably in rooms only having a floor drain (for prevention of damage by water flooding). A stop cock must be fitted before such a flexible tube.

12.190

Concealed fixtures - valves shall preferably be fitted in the open, and remain accessible for repair and easy replacement. Where concealed installations are required only specially designed valves for these purposes shall be utilized.

13.110

FIRE HYDRANTS SHOULD BE SITED IN A BUILDING ON ADVICE OF THE FIRE AUTHORITY

13.120

Installations of fire hydrant pipelines require separate distribution lines, to ensure an adequate supply of water for the fire hydrants. In case of low pressure systems adequate roof tank capacity and pipelines of larger diameters must be provided.

13.130

A connection from the fire hydrant to regularly used sanitary apparatus (water closet) should be made in order to provide for water renewal. For pressure lines this should be at the highest point of the building and for low pressure systems at the lowest point.

13.140

A minimum of 3” diameter pipe should be installed for fire hydrants.

13.150

The fire hose (e.g canvas) has to be long enough to be able to cover the entire area with water.

13.160

The hydrant locations have to be near doors and stairs, in order to secure operation and escape.

13.170

The hydrants must be accessable to all people in the building (for 24 hours a day): no locks on cabinets. The fire hydrants need a large “F” sign on doors of cabinets.

14.100

To secure regular water supply and avoid damage, pipelines fitted in places with sub-zero temperatures require special attention. Security can partly be achieved by proper installation, however, when systems inside the buildings are left without room heating they need to be drained.

The following should be observed:

a) Feed line from mains to be underground (1 meter deep) Pipelines have to be inside the building as much as possible.

b) Main valve to be inside the house, having a drain valve at the lowest point. The drain valve has to be operated before freezing conditions occur, and must be left open until system is refilled.

c) All pipes to be fitted with constant slope towards either the taps or the lowest drain point. A proper ventilation is also required to guarantee a through drainage (top-most valve or ventilation pipe).

d) Pipelines not to be concealed in outer walls.

e) Consider whether pipes could be fitted on walls or in ducts - keeping distance from walls by means of clamps - and insulation added where required.

f) Pipelines not to pass through shafts, chimneys, etc., and to remain accessible as much as possible.

g) Hot water tanks to be fitted inside the house, with easy draining facility.

h) Pipelines and valves exposed to outside temperatures (pump line, pipeline in roof, vent pipe) probably require good pipe insulation.

i) The use of G.I. pipes in the house is recommended, they could be thawed by flame heat. (HDPe pipes have the advantages as they will not crack in normal circumstances, but if they freeze they cannot be thawed by flame heat).

k) Water storage tanks and pipelines may require lagging to prevent freezing of the water, especially when fitted in cold roofs. The insulation shall be of inorganic materials.

15.100

Proper dimensioning is essential to guarantee a trouble-free supply of water, in sufficient quantity and with sound controls.

15.200

THE DIMENSIONS CAN BE CALCULATED IN TWO WAYS:

1) With tables (see table 15.460) for procedure for normal house installations,

2) Through calculation.

15.300

FOR NORMAL INSTALLATIONS THE FOLLOWING LOSSES OF HEAD CAN BE ACCEPTED:

- The flow-pressure (dynamic pressure) may not be less than approx. 0.5 kg/cm2 (7 lb/in2) and the total loss of head in the entire installation may not be more than 1 kg/cm2 (14 lb/in2).

15.400

NORMAL HOUSE INSTALLATIONS

Loading values of taps and aparatus

Utility

valve diameter

units

Washbasin, hand washbasin, bidet, flushing cistern, single tap

1/2”

0.5

Kitchen sink, service sink, dish washing machine, laundry trough, wash sink

1/2”

1.0

Bath mixer, shower mixer, wash fountain, washing machine (up to 6 kg)

1/2”

2.0

15.420

Hot and cold water connections must be taken into account separately for calculating the connection value even though they may be at a joint mixer.
For example: 1 washbasin 1/2”

Coldwater 0.5 U
Warmwater 0.5 U
Total Units 1.0 U

15.430

Water heater connection-dimensions will be according to the loading unit of the apparatus, i.e. the total of all units connected to the hot water system. For example: 4.0. U = 3/4”, or 8.0. U = 1”

15.440

One loading unit (1.0.U) corresponds to a medium water consumption of 10 liters/minute. In respect to quantities of 5 liters/minute, or less, the unit is taken as 0.5 U.

15.450

For installations with high simultaneous draw-off (schools, canteens, hotels, etc.), a higher consumption must be considered, e.g. by doubling the value of the units.

15.460

TABLE FOR DIMENSIONING WITH UNITS

15.461

A) For systems with roof tanks (Head less than 40 meters)

LOADING VALUES AND DIAMETERS (G.I. PIPES)

PIPE DIAMETER IN INCHES

MAX. LOADING UNITS

1/2

0.5 - 2.0

3/4

2.5 - 4.0

1

4.5 - 10.0

1 ¹/₄

10.5 - 20.0

1 ¹/₂

20.5 - 40.0

2

40.5 - 100.0

0.5 UNIT

1.0 UNIT

2.0 UNIT

´

15.462

B) For systems with pressure
(Head above 40 meters)

LOADING VALUES AND DIAMETERS (G.I. PIPES