Handbook on plumbing installation

Then replace on the shower rod and spread it out straight to dry. Clean prefabricated shower cabinets with soap and hot water, but never with a gritty abrasive. New shower cabinets usually have fiberglass or acrylic walls which will not withstand heavy scouring powders. If you stand in it to wash the inside walls of the cabinet the receptor should be protected by a heavy cloth or papers.

Chrome plating is a hard and durable finish that requires little attention except for the occasional washing with soap and water. Salt air or other corrosive atmospheres have a destructive effect on chrome. Where chromium- plated fittings are exposed to these agents, it is important to wash them frequently. After they are washed and dried, it is advisable to apply a protective coating such as ordinary furniture wax. Green spots may appear on chromium plating.

If this happens, prevent the rust from spreading by scouring the spots with the same kind of powder which manufacturers recommend for enameled, cast iron fixtures. When the spots have been removed, apply a Fin of wax. Your plumber will be glad to help you select a good cleanser. Therefore, take care of the source—the water heater. If you have a gas or electric water heater, keep the temperature dial setting at or below the suggested Factory Energy Savings Settings listed on the water heater.

Above that mark means excessive wear on the water heater and the potential for scalding. The burner of a gas-fired water heater is easily accessible and should be checked by your plumber periodically to keep it clear of dust or sediment. The flame at full fire should be a light to dark blue. If the flame is more orange or yellow, the gas pressure or air flow needs to be adjusted.

You can keep your water bills low by tempering all hot water as it is used. Letting the hot water faucet run on and on wastes not only water but fuel as well. All domestic water heaters are required to be equipped with a relief valve as a safety feature to prevent damage from excessive pressure and temperature.

There is always danger that this valve may become frozen or corroded from long disuse. For this reason, it is advisable to trip the lever of this valve manually every two or three months to be sure it will operate freely if an emergency arises. Note: The discharge will be hot water that will need to be contained in a pan or bucket or allowed to drain to a floor drain. If you find a leak in your plumbing system shut off the water supply and call your plumbing contractor at once.

Water supply systems are under high pressure. Temporary repairs are only temporary and wrapping the pipe usually fails. Leaks must have immediate attention, since they can progress into a serious break in a hurry. Frozen plumbing pipes, although inconvenient, do not constitute a calamity.

The calamity may come if the pipes are thawed with a blow torch, and if the open flame or the torch is allowed to come too close to combustible material, such as insulation, wooden joists or flooring. Another danger from the use of a torch arises when both ends of a pipe are clogged with ice and when the heat is applied in the center. The application of the heat of the torch at the center of the pipe is likely to cause the water to flash into steam potentially causing an explosion with disastrous results for the user of the torch.

It is far better to adopt the slower and more conservative procedure of melting ice by the use of a blow dryer, or heat gun. Preventing Frozen Pipes. Before the cold freezing weather sets in, make sure that all the garden hoses outside your home are disconnected. Failing to do so can cause not only the hose but also the hose bib to which it is connected, to freeze and be damaged.

This is especially important with anti-freeze hydrants. The hose must be disconnected to make the faucet freeze-proof. Failure to do so will trap water in the faucet body, which then can freeze. If the hose is disconnected, the anti-freeze faucet can properly drain, and this will prevent freezing.

Water pipes which are exposed to freezing temperatures or drafts should be covered with insulation. Whenever possible it is best to drain systems not being used in severely cold weather.

Small water pipes will freeze quicker than will waste or sewer pipes. Never leave a garage door open in severely cold weather, if there is plumbing in the garage. The cold and draft can freeze water lines in minutes. Pipes located in unheated basements or garages should be insulated with a commercial covering. In designing the plumbing system for a new house, a plumbing contractor will endeavor to make it as noiseless as possible.

Manufacturers of plumbing fixings are making every effort to reduce the noise connected with the operation of their equipment, and contractors have been very successful in eliminating much of the noise formerly associated with plumbing systems. Because so much of the noise is due to water traveling at a high velocity, it follows that whatever can be done to reduce the velocity of the water will correspondingly reduce the noise in the system.

It is for this reason that it is so important not to skimp on the size of the water supply piping. Larger pipe will not only provide a more adequate supply of water but will reduce noise. There are three general types of noises found in some of the older plumbing systems.

These are water hammer, whistling and chattering. Water hammer is the thump in the piping heard when faucets or valves are turned off abruptly. There is no excuse for water hammer. It can usually be eliminated by the installation of an air chamber or short length of pipe in the wall where each supply pipe enters a plumbing fixture. In some cases, however, the ordinary type of air chamber will not prevent water hammer.

In such cases, special devices known as shock arrestors should be installed on the main line near the meter or as close as possible to the cause of the noise. Sometimes water hammer is due not to the plumbing in the house in which it is heard but to a condition outside of the house, either along the water main or in a neighboring house.

In such cases, skillful detective work by an experienced master plumber is necessary to ferret out the source of the trouble and to plan corrective methods. Water hammer should not be permitted to go on indefinitely. The noise is only an audible symptom of what is going on in the piping. The piping is being subjected to the wear and tear of a multitude of shock waves. The result will be leaks in piping, tanks or fixtures unless the condition is corrected.

Chattering in the piping may be caused by loose pipes, by pipes rubbing against a metal projection, by worn faucet washers or looseness of other inside parts.

Whistling is caused by the speed of water flowing through piping which is usually too small. A pressure reducing valve will help as will a general straightening out of the plumbing system. Whistling is most common at bends and tees in the pipe. Due to condensation of water vapor in the air, beads of moisture will form in warm weather on any pipes and fixtures containing cold water.

Normally, when not in use, the water and fixtures will worm rapidly to room temperature and the condensation will stop. When a closet tank or other fixture continues to sweat for hours after it has been used, it is a sign that cold water is continuing to flow through it, possibly due to an improper adjustment of the tank valve or a leak.

Sweating pipes can be wrapped with an insulation material which prevents the condensation and formation of moisture. The well-designed and correctly installed plumbing system is odorless. Odors are most likely to arise from leaks in the waste or vent piping or from traps which have lost their water seal.

In an incorrectly installed system, there are, of course, many opportunities for odors to result from defects in the system, particularly if it is not properly vented. Unusual odors should never be ignored. Such odors are often an indication that sewer gas is present. Sewer gas, while not always deadly, is noxious and capable of causing headaches and other minor illnesses.

Sewer gas is foul smelling air and should be prevented from entering the house. If it is suspected that sewer gas is entering through a leak in the piping, a plumber will subject the system to a test either by means of smoke, water or oil of peppermint. The test will indicate the location of the leak. In order to explain how the sewer gas may enter a house through a plumbing fixture, it is necessary to clarify the function of traps and vents.

Every plumbing fixture is the terminus of the city water supply system and the beginning of the city sewerage system. The faucets control the water supply. The traps and vents control the sewer air. They do so by a very simple method. Sewer air will not penetrate a water barrier. Therefore, a device is employed which keeps several inches of water between the house air and the sewer air. This is the trap, which is plainly visible under such plumbing fixtures as sinks and lavatories.

It is built into water closets. In the case of bathtubs and shower cabinets, it is usually concealed in the floor or basement. The arrangement of the meter position s and the door opening of the meter box shall be arranged in such a manner that staff of the Water Authority would not be required to lean inwards to take meter meter readings or carry out maintenance works. The lock of the door to the meter room shall be located at a level between 0.

The door to the meter room shall be equipped with handle to facilitate door opening. The door handle shall be either in the form of long cylindrical or spherical shape to facilitate handling. The top of the board shall not be higher than mm above the floor level and the bottom of the board shall not be lower than mm for an individual meter above the floor level.

This display board shall be constructed of durable plastic or corrosion-resistant plate engraved e ngraved with words and diagrams in black on light colour background. The wordings should be of font size s ize not less than 18 pt. This requirement can be waived for small meter boxes accommodating 3 meters or less.

For meters arranged in groups, no meter position shall be lower than mm nor higher than mm above the floor level. This requirement is also applicable for water meters installed inside meter boxes. For Housing Department estates where corridor meter arrangement is chosen and accepted, individual meter positions shall be at a suitable height not less than mm but not more than mm above the floor level. The meter position of a building supply to a construction site shall be provided within a 16 July 14 meter room or meter box located at the hoarding recess area so that reading and maintenance of the meter can be carried out outside the construction site.

The door of the meter room or meter box shall be made of chicken-wire or provided with see-through glass panel. Details of the meter room or meter box are subject to the approval of the Water Authority.

For a meter installed in a landscape area, it should be installed above ground level with a clear working headroom not less then 2m. A safe pedestrian access to the meter position should be provided. When the meters are sited at roof level, fullway gate valves shall be fitted before meter positions.

For connections up to and including 40 mm diameter, a loose jumper type stopcock shall be provided and placed with spindle in the vertical position at each meter position on the inlet side of the meter where the meter is not sited at roof level and where wher e the pressure is considered adequate.

For connections larger lar ger than 40 mm diameter, a fullway gate valve shall be provided before the meter position and a non-return or check valve fitted on the delivery side as close as possible to the meter position. The purpose of introducing master metering is to detect water leakage and unlawful taking of water before meters.

A master m meter eter room to house the master master meter and its by-pass arrangement should be provided as close to and within the boundary boundary lot as possible. These requirements shall apply to all plumbing plumbing proposals first submitted to the Water Authority after 31 December Also, check meter positions shall be provided in fresh water and TMF inside service and fire service.

There will be 1 master meter installed in each set of connection connection points at the lot or building boundary. Twin or or dual main connections are regarded as one set of connection points.

The length upstream and downstream should not be less than 10 times the nominal diameter of the master meter and 5 times respectively. Please refer to Fig. Also, the metering characteristics of both supplies are different.

Therefore, fire service needs to be separate from the potable supply right at the lot boundary. A typical configuration of master meter is shown in the Figs. For check meter of diameter larger than mm, the straight lengths upstream and downstream are 10 x D and 5 x D respectively.

The designer should provide minimum horizontally perpendicular and longitudinal working clearances at each check meter position. The table below stipulates the minimum horizontally perpendicular working clearance, meaning the shortest distance between the longitudinal centre line of the check meter position and a wall or any edge of a door when opened. Meter Size mm Minimum horizontally perpendicular working 40 50 80 clearance from the wall or any edge of a door when opened where the check meter position is clamped Distance A mm as shown in Fig.

Inside Service 6. However, in order to ensure that consumers can enjoy good quality of water at the taps, building owners have to maintain their plumbing systems properly as well. All domestic supplies and concessionary supplies shall be separately metered.

For different usages of concessionary supplies, please see Section 6. The Water Authority may approve other pipe materials for use in water supplies from time to time. However, this requirement does not apply to pipes and fittings installed prior to 23 December nor to minor repairs to such plumbing works. The Water Authority may also accept pipes and fittings of other standards equivalent to the British Standards. To this end, the consumer or agent 21 21 concerned shall clean and disinfect a newly installed fresh water inside service before it is given a supply supply from the Water Water Supplies Department.

Besides, after repair or maintenance of fresh water inside service, if there is a possibility that extraneous materials can get into the inside service, the inside service shall be cleaned and disinfected before water supply is resumed. The guidelines guidelines below on how how to clean and disinfect the fresh water inside service are set out for general reference: A Newly Installed Fresh Water Inside Service The newly installed fresh water inside service shall be cleaned and disinfected to the satisfaction of the Water Authority in accordance with the following procedures.

Fill the fresh water mains slowly with water water and carry out the required water pressure testing. If the result of the test is satisfactory, clean the fresh water mains internally and flush them with with potable water. For fresh water mains of sizes less than mm mm in diameter, swab to remove the dirt and materials inadvertently left in the water mains and flush them with potable water. The concentration of the solution has to meet the requirement that when the water mains are filled up with water, the free chlorine in the water will be at least 30 ppm.

Keep the water mains under disinfection for at least 24 After disinfection, disinfection, flush the water mains mains thoroughly thoroughly with potable water. The test parameters and the related acceptance criteria are listed in Appendix A3. Any contamination in underground mains may lead to pollution of the government supply. To ensure quality quality control control and minimize the risk of pollution pollution to the government supply, the Water Authority will carry out sampling and analysis for this part of inside service.

If the results are satisfactory, the fresh water mains can be put into If not, not, the above above disinfection and testing procedures procedures shall be carried out again. In this respect, Licensed Plumbers are advised to allow sufficient time for the Waterworks Chemists to carry out sampling and analysis and to avoid arranging disinfection immediately before long public holidays.

Methods Using Chlorine as a disinfectant i Fill the inside service concerned with a homogeneous homogeneous solution of chloride of lime for disinfection.

The concentration concentration of the solution has to meet the requirement that when the inside service is filled up with water, the free chlorine in the water will be at least 30 ppm. After keeping the inside service under disinfection for at least 24 hours, the inside service shall be immediately drained and thoroughly flushed with potable water. If the free residual chlorine measured at the end of the contact period is less than 30 ppm, the disinfection process shall be repeated.

After successful disinfection, the inside service shall be immediately drained and thoroughly flushed with potable water. The Water Authority will advise the applicant of any additional test parameters and related acceptance criteria for water samples i. The test parameters and the related acceptance criteria are listed in Appendix A3 Note: See Note of Paragraph 2 iii above also if non-chlorine based disinfectant is used.

If the results are satisfactory, the fresh water inside service can be put into operation. If not, not, the above above disinfection and testing procedures procedures shall be carried out again.

If an accredited laboratory is arranged to carry out the sampling and analysis, the 2 The accredited laboratory shall be accredited for all the individual parameters listed in Appendix A3. In this respect, Licensed Plumbers are advised to allow sufficient time for the Waterworks Chemists or the accredited laboratory to carry out sampling and analysis and to avoid arranging disinfection immediately before long public holidays.

If the trench is flooded, pump water out of the trench. The concentration of the solution has to meet the requirement that when the water mains are completely filled with water, the free chlorine in the water will be at least 30 ppm. Fill the water mains with water and isolate them when filling is Keep the water mains under disinfection for at least 30 minutes. After disinfection, flush the water mains thoroughly with potable water through a fire hydrant, washout or, if no such facilities are available, through a submain temporarily put out of service.

The concentration of the solution has to meet the requirement that when the inside service is completely filled with water, the free chlorine in the water will be at least 30 ppm. Isolate the inside service when filling is completed and keep the inside service under disinfection for at least 30 minutes. After disinfection, flush the inside service thoroughly with potable water. To minimize the possibility of bacteria growth after putting an inside service into operation, water outlets which are infrequently used or are connected to stagnant water supply pipeworks shall be flushed at full flow for a minimum period of one minute at least on a weekly basis and before use.

For a change in the supplier or supplier's agent for a product by the same manufacturer, it is not necessary to make a re-submission. All fittings to be installed in the water supply plumbing system must fall within one of the above categories in respect of their types and origin as approved by the Water Authority and conform to the waterworks requirements.

Under Category c of compliance of water supply fittings, the Water Authority issues acceptance letters for draw-off taps, stop valves, gate valves, ball valves, mixing valves and combination fittings. To apply for approval of water fittings, the applicant is required to submit a test report original or certified true copy together with 6 copies of the catalogue of the fittings under a covering letter to the Water Authority.

No application form is required. Provision shall be made for checking leakage from any plumbing work laid underground. If the connection is not laid in an exposed manner at the lot boundary, then it shall be laid underground with an adequate cover.

For carriageway a minimum cover of mm is usually required. All underground plumbing works will be inspected by the Water Authority before it is backfilled or covered up. As the treated municipal water supply to the whole territory of Hong Kong conforms chemically and bacteriologically to the Guideline Standards for Drinking Water of the World Health Organisation and is monitored closely by extensive sampling at treatment works, distribution networks and consumers' taps.

They may be installed in an indirect supply system via the storage tank where there is no possibility of contamination of the mains supply, or of the supply to other premises, e. As contaminated water in the filter can backflow to communal water supply system or upstream, the Water Authority does not recommend the installation of any water filter.

When there is installation of any domestic filter or water filter incorporated in water using apparatuses such as drinking fountain etc. The Water Authority does not require any test results of the filters before installation, i. Despite the above, customers should carry out proper maintenance of water tanks and pipes in their buildings so as to maintain the water quality and to reduce the possibility of pollution arising from the use use of water filters.

Regular maintenance of domestic water filters is also equally important. For individual construction sites, metered water supply may either be tapped directly from the mains or from a fire hydrant. In cases of boring works for site investigation and location of sites are not confined to one particular area or the limit of the works area makes it technically impracticable for the installation of building supply meters, the applicant may apply for a meter adaptor adaptor to draw a supply from any fire hydrant hydrant near to the works area.

Supply may be given provided it is technically feasible and Waterworks requirements are met. Applications for metered water supply can be considered and approved with a statement which dissociates the approval from the legal status of the structure if it is technically feasible and Waterworks requirements are met.

An example of such case is the use of mains water for the evaporative type air-conditioning system to serve those areas in hospitals, such as the operating theatres, intensive care units, mortuary etc. The type of evaporative plant used should be of an enclosed design from which wastage of water by splashing is prevented. In order to promote the use of more energy efficient air-conditioning systems in Hong Kong, a pilot scheme for the application to use fresh water for non-domestic air-conditioning in selected areas i.

The pilot scheme is converted to the standing scheme on 1 June Such approval will be withdrawn if in the opinion of the Water Authority the supply situation requires it. Additional connection point may be given only when physical barrier exists preventing extension of the drip feed irrigation system and the distance of two successive connection points exceeds 40 m. This category of concessionary usage must be supplied off tank. Supply may be permitted only if there is no practical alternative.

Recycling of water is required unless it is demonstrated to be impracticable. This category of concessionary usage 31 must be supplied off tank. The purpose of having some of the concessionary supplies to be supplied off tank is to prevent contamination of the supply source through back siphonage. Additional connection point may be given only when physical barrier exists preventing extension of the drip feed irrigation system and the distance of two successive connection points exceeds 40 m.

This category of concessionary usage must be supplied off tank. Supply may be permitted only if there is no practical alternative. Recycling of water is required unless it is demonstrated to be impracticable. The purpose of having some of the concessionary supplies to be supplied off tank is to prevent contamination of the supply source through back siphonage.

Similar provisions should also be considered for other categories. Installation of water points for internal cleansing of open yards and for other miscellaneous domestic purposes in private houses of bungalow type or the like can be permitted as part of the domestic supply.

This will not be taken as a concessionary supply. Pressure type thermal storage heaters other than unvented electric thermal storage water heaters shall be supplied from a separate mains water storage cistern, no matter what the pressure at inlet point should be, except these are installed in flats supplied through the indirect or sump and pump system.

They shall be provided with a vent or an expansion pipe taken from its highest point and discharge in the atmosphere above the storage cistern at sufficient height to prevent a constant outflow of hot water therefrom. For flats supplied from the roof storage cistern of an indirect or sump and pump system , no separate storage for hot water apparatus will be required but the supply to the apparatus shall be by a separate down feed supplying the apparatus only unless the flats on the indirect system are supplied through an oversized down feed pipe, for which case the pipe supplying the hot water apparatus shall be branched from the down feed at a point above the top of the apparatus.

Some heaters, such as gas geysers and instantaneous type electric water heaters, may require a minimum pressure and flow for their proper functioning. When these heaters are to be installed, their suitability shall be checked against the available pressure and flow, especially for the uppermost floors served by the direct system or the indirect system. If mixing valves, water blenders or combination fittings are to be used, the cold water supply to these fixtures shall be drawn from the same source that supplies the hot water apparatus in order to provide a balanced pressure and to obviate the risk of scalding should the supply at the source fail or be restricted for any reason.

The safety devices of unvented storage type electric water heaters are under the control of the Electric Products Safety Regulations administered by the Electrical and Mechanical Services Department.

For the installation of unvented electric thermal storage type water heaters, the drain pipe provided for the relief valves shall be installed in such a manner that the water released from the valves shall be discharged to a safe and visible location. Prior approval must be obtained from the Water Authority. In either case the vent or expansion pipe shall discharge to the atmosphere above the storage cistern at sufficient height to prevent a constant outflow of hot water therefrom.

Such valve shall be set to discharge when the pressure in the boiler exceeds 35 kPa above that of the static pressure of the system.

If mixing valves, water blenders or combination fittings are to be used, the cold water supply to these fixtures shall be drawn by a separate down feed from the same water storage cistern supplying the hot water system. This outlet shall be slightly lower than the feed to the hot water system in order to provide a balanced pressure and obviate the risk of scalding should the mains supply fail or be restricted.

A screwed plug with a removable key shall be provided at the lower part of the system for the purpose of draining down or emptying the system. No stop valve shall be installed in the primary flow or return pipes except when a vent pipe is connected to the boiler and such installation shall only be made under skilled supervision. No tap or other means of drawing off water other than a screwed plug with a removable key for emptying the system for cleansing and repair shall be connected to any part of the hot water system below the top of the hot water cylinder in such a way that the level of water in the cylinder can be lowered.

In a hot water system comprising more than one storage cylinder at different levels, this requirement should apply to the lowest cylinder. The hot water taps shall be fixed at a distance from a hot water apparatus or from a flow and return system not greater than 12m for pipes up to and including 20 mm diameter, 8m for pipes up to 25mm diameter, and 3m for pipes above 25 mm diameter.

To avoid waste of water when repairs are being effected, a stop valve shall be fitted on the cold feed pipe at the outlet from the storage cistern. If the storage cylinder is installed at a lower floor, and additional stop valve shall be fitted near the inlet to the cylinder.

The inside service for flushing water supplied from privately owned wells, nullah intakes, stream intakes or other water source need not comply with the Waterworks requirements. If it is foreseen that flushing supply from government supply system is likely to be required, the flushing system should comply with the Waterworks requirements in order to minimise the modification work required at a later stage.

A water meter shall be installed at each flushing system receiving a temporary mains fresh water TMF supply. TMF flushing supply is normally given to the entire building through a communal meter. Hence, application for flushing supply should be submitted by a representative of the building and application for individual units is not entertained. Salt water flushing supply is also subject to the bulk application but it is not metered.

However, a meter position shall be provided for consumption check and waste detection purposes. It shall be close to the lot boundary or close to the point of connection from the internal distribution mains whichever is applicable. The Water Authority may approve other pipe materials for use in salt water inside service from time to time. Pipes on a salt water inside service shall be made of salt water resistant materials, e.

Every water closet, latrine shall be provided with a flushing cistern which shall have an overflow terminating in a conspicuous position. It is the requirement under Buildings Ordinance that all new buildings shall be provided with a system of plumbing for the supply of water for flushing purposes and every part of such system of plumbing including the storage tank shall be constructed of material that is suitable for use with salt water. The storage tank is used to guard against contamination, accidental interruption of supply and to even out peak demands.

Direct boosting from salt water mains is not permitted. Such flushing supply should be given on a temporary basis and shall revert to salt water supply when this becomes available. When salt water becomes available in areas containing premises using fresh water as a temporary alternative, the Water Authority will inform the consumers that permission to use fresh water will be withdrawn in 3 months' time and salt water will be provided in lieu.

Consumers will also be informed of the estimated cost of the salt water connection. The current Waterworks Regulations require that flushing cisterns shall be of the valveless syphonic type capable of giving a flush between 7.

However, a disadvantage of valveless syphonic type cisterns is that they require a comparatively larger volume of water to generate the necessary flushing effect and a cistern volume of 7.

With the improvement in design and material, valve type flushing devices have become more reliable in their performance. A major advantage of valve type flushing devices is that they can give instantaneous flushing even with a relatively smaller volume of flushing water.

This helps reduce water required for flushing. This allows further reduction in flushing water requirement. An essential requirement on the relaxation on the use of valve type flushing devices is that the design flushing volume should be compatible with the bowl to ensure effective clearance of waste by a single flush. For the use of flushing valves, a good management system ensuring frequent inspection and cleaning of filters is required.

Normally, only public toilet with good management will be considered for the use. Otherwise, the installation of a filter readily accessible for inspection and cleaning is suggested. The Water Authority will proceed to amend the Waterworks Regulations for the above changes. The proposed amendments to the Waterworks Regulations shall not apply to existing flushing apparatuses including valve type flushing cisterns without the approval of the Water Authority installed before the commencement of the new Regulations.

No person shall be required to alter or renew any such flushing apparatuses by virtue of the amendments unless such flushing apparatuses are in the opinion of the Water Authority so defective or in such condition as to cause waste. The identification can be done by following step by step a planned operation procedure and test methods such as chemical tests.

It is also important that any newly laid pipework should not be put into use before it has been inspected and approved by the Water Authority. Fire Service The Director of Fire Services is responsible for approving proposals for installations of or zyxwvutsr alterations to fire services.

Only the plumbing system of the fire service is subject to the requirements of the Water Authority. For installations which are to be connected to government mains, the method of supply and the materials used must be subject to the approval of the Water Authority and their installation should comply with the Waterworks requirements.

The fire service should be designed to guard against contamination, waste and misuse. However, check meter positions shall be provided for consumption check and waste detection purposes.

It is also to remind that use of water from fire service for purposes other than fire fighting is prohibited. The check meter position shall be close to the lot boundary or close to the point of connection from the internal distribution mains whichever is applicable.

The Water Authority may approve other pipe materials for use in fire service from time to time. Pipes on a fresh water fire service shall be made of cast iron, ductile iron, galvanized wrought iron, galvanized steel or copper of approved standards. Consideration can be given zyxwvutsr for the use of wrought iron pipe and black steel pipe without being galvanized, upon application, for a fresh water fire service after a positive air break i. Pipes and fittings on a salt water fire service shall be cast iron, ductile iron and fittings capable of withstanding the corrosive effect of salt water.

The fire service must be entirely independent of other water supply arrangements within the building or development concerned. Such priming arrangements must be approved by the Water Authority prior to installation. All pipeworks before check meter positions shall be exposed or laid in a proper service duct to facilitate inspection and repairs.

Provision shall be made for checking leakage from any pipeworks laid underground. It is designed to: i detect a fire; ii give an alarm; iii attack and contain an outbreak of fire until the arrival of the Fire Services. Drencher system is a system of pipes designed to operate either automatically or manually and provide a curtain of water over buildings which constitute a particular dangerous fire hazard e. Any exemption from this requirement should have the endorsement of the Director of Fire Services.

The licensed plumber and the Authorized Person if applicable shall certify that the pipes and fittings to be installed and any materials to be used for the construction, installation, alteration or removal construction etc. Before commencement of plumbing works, when signing Form WWO 46, the licensed plumber should take all necessary steps to ensure that the pipes and fittings to be installed and any materials to be used shall be as prescribed by the Waterworks Regulations.

WWO46 form should be in A4 size. The original will be disposed of and will not be returned to the LP. This needs to be done before staff of the Water Authority conducts inspection. Interim Inspections and Final Inspections After completion of plumbing works, the licensed plumber concerned is required to report completion to the Water Authority and requests the Water Authority to inspect the completed works via the submission of Form WWO46 Part IV.

The inspection will be an interim inspection when the completed works are only part of the plumbing works such as underground pipeworks or an inside service or a fire service to be concealed. On the other hand, when the completed works are the whole of the plumbing works, the inspection conducted by the Water Authority will be a final inspection. The interim inspection will be carried out on a random basis and applied a risk based approach. Completion of Work xtsnige After completion of plumbing works, the licensed plumber should report completion of work on Part IV of Form WWO 46 and request the Water Authority to arrange for final inspection.

Furthermore, neither the approval of the plumbing proposals nor the granting of the connection to the main and the installation of the part of the fire service or inside service on land held by the Government shall be construed as a ratification of any contravention of any of the provisions of the Waterworks Ordinance or the Waterworks Regulations.

For details, please refer to the website of 4. Generally, works of a minor nature are works which can be completed without the involvement of specialised trade skill that requires specific knowledge and ability acquired through designated training for carrying out the works, and those which do not change the general arrangement of the plumbing installation already approved by the Water Authority, or affect the flow conditions of the plumbing system thus causing possible supply problems.

The following minor alterations and repairs to inside services without dismantling and reinstallation of the water meter within a domestic premises may be exempted as follows:- i Replacement of defective piping, taps, stopcocks, gate valves, ball valves and work of a similar nature.

Minor alterations and repairs to inside services shall conform to waterworks requirement in respect of quality of workmanship and material. For the avoidance of doubt, all plumbing works using soldering for connecting copper pipes shall have the permission of the Water Authority and shall be undertaken by a licensed plumber in accordance with Section 14 and 15 of WWO.

As alterations, addition and extension to the existing plumbing installation may cause a change in the flow conditions in one way or another, it is in the interest of the 4. The addresses and office hours of Customer Enquiry Centres are: 1. Metering 5. General Metering is required to measure water consumed for billing purposes. Meter position shall be provided by the LP employed by the applicant for meter installation while water meters will be provided by the Water Authority.

Water meters may be installed either by the Water Authority or the licensed plumber. The size and location of the water meter will be determined by the Water Authority.

For domestic supply, a meter size of 15mm is usually recommended. For trade and industrial supply, the meter size is determined based on the actual water consumption. Meter Position The meter position for a 15 mm diameter meter shall be constructed to include 20 mm x 15 mm bushes at both sides of the meter position with a mm clear effective length distance piece of 15 mm tube placed in between refer to Fig 3.

The tube shall be hollow with conspicuous holes drilled through the body. A long screw connector shall be provided immediately after the bush at the delivery side. The meter position for meter of all sizes shall also be similarly provided with corresponding fittings of appropriate sizes. All water meters, including vacant meter positions and check meter positions, shall be arranged in groups and housed in meter rooms or meter boxes.

Besides, if the door to the meter room is to be opened at an inward position and it is at the opposite side of the meter group, the minimum perpendicular distance between the outward face of the meter group and the door the point on the door that is nearest to the meter group when it is fully opened shall be mm; b the clear width and height of the door entrance to the meter room shall not be less than mm and mm respectively.

The arrangement of the meter position s and the door opening of the meter box shall be arranged in such a c manner that staff of the Water Authority would not be required to lean inwards to take meter readings or carry out maintenance works. The lock of the door to the meter room shall be located at a level between 0.

The door to the meter room shall be equipped with handle to facilitate door opening. The door handle shall be either in the form of long cylindrical or spherical shape to facilitate handling.

The top of the board shall not be higher than mm above the floor level and the bottom of the board shall not be lower than mm for an individual meter above the floor level. The wordings should be of font size not less than 18 pt. This requirement can be waived for small meter boxes accommodating 3 meters or less. For meters arranged in groups, no meter position shall be lower than mm nor higher than mm above the floor level.

This requirement is also applicable for water meters installed inside meter boxes. For Housing Department estates where corridor meter arrangement is chosen and accepted, individual meter positions shall be at a suitable height not less than mm but not more than mm above the floor level. Details of the meter room or meter box are subject to the approval of the Water Authority.

For a meter installed in a landscape area, it should be installed above ground level with a clear working headroom not less then 2m. A safe pedestrian access to the meter position should be provided. When the meters are sited at roof level, fullway gate valves shall be fitted before meter positions.

For connections up to and including 40 mm diameter, a loose jumper type stopcock shall be provided and placed with spindle in the vertical position at each meter position on the inlet side of the meter where the meter is not sited at roof level and where the pressure is considered adequate. The purpose of introducing master metering is to detect water leakage and unlawful taking of water before meters. The details of implementation of the policy are as follows: a i For all new developments, except single detached village type buildings and single block buildings, plumbing designers shall be required to provide master meter room with master meter position s in the plumbing, submit undertaking Form WWO for the consumership s of master meter s and arrange licensed plumber to install master meter s.

There will be 1 master meter installed in each set of connection points at the lot or building boundary. Twin or dual main connections are regarded as one set of connection points. To ensure accuracy of master meter, the plumbing designer shall provide two lengths of straight pipe, one upstream and one downstream of the master meter. The length upstream and downstream should not be less than 10 times the nominal diameter of the master meter and 5 times respectively.

Please refer to Fig. Also, the metering characteristics of both supplies are different. Therefore, fire service needs to be separate from the potable supply right at the lot xtsnige boundary. A typical configuration of master meter is shown in the Figs. Check Meter Check meter positions shall be provided in fresh water and TMF inside service and fire service. For check meter of diameter or smaller, a straight length of pipe of 5 x D where D is the nominal bore of the meter should be provided upstream of the check meter position and a straight length of pipe of 2 x D at downstream.

For check meter of diameter larger than mm, the straight lengths upstream and downstream are 10 x D and 5 x D respectively. The designer should provide minimum horizontally perpendicular and longitudinal working clearances at each check meter position. The table below stipulates the minimum horizontally perpendicular working clearance, meaning the shortest distance between the longitudinal centre line of the check meter position and a wall or any edge of a door when opened.

Meter Size mm 40 50 80 Minimum horizontally perpendicular working clearance from the wall or any edge of a door when opened where the check meter position is clamped Distance A mm as shown in Fig.

Inside Service 6. Pipe Materials 6. However, this requirement does not apply to pipes and fittings installed prior to 23 December , i. Water Regulations Advisory Scheme or c accredited laboratories acceptable to this Authority. However, in order to ensure that consumers can enjoy good quality of water at the taps, building owners have to maintain their plumbing systems properly as well.

Metering Requirement zyxwvutsr All fresh water supplies to inside service shall be metered. All domestic supplies and concessionary supplies shall be separately metered. For different usages of concessionary supplies, please see Section 6. To this end, the consumer or agent concerned shall clean and disinfect newly installed fresh water inside service before it is put into use.

Besides, after repair or maintenance of fresh water inside service, if there is a possibility that extraneous materials can get into the inside service, the inside service shall be cleaned and disinfected before water supply is resumed. The guidelines on how to clean and disinfect the fresh water inside service and the requirement of water sampling test are set out in WSD Circular Letter No. Plumbing Arrangements 6. Provision shall be made for checking leakage from any plumbing work laid underground.

If the connection is not laid in an exposed manner at the lot boundary, then it shall be laid underground with an adequate cover. For carriageway a minimum cover of mm is usually required. All underground plumbing works government projects are exempted except projects of Housing Authority will be inspected by the Water Authority before it is backfilled or covered up.