Plumbing and Sanitary Services

Building Services

Plumbing And Sanitary Services 2011/12 Semester 2

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Scope of Lecture Types of pipe and valve §  Water supply system § 

§  §  §  § 

§ 

Mode of water supply Water contamination Cleaning and sterilisation for water supply system Water conservation measures

Sanitary plumbing system §  §  § 

Definitions of terms Traps and trap seal Types of sanitary plumbing system

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Pipe materials Commonly used piping materials in building plumbing/sanitary systems: §  §  §  §  §  §  § 

Cast iron pipe Ductile iron pipe Galvanised steel pipe Concrete pipe Copper pipe Stainless steel pipe UPVC pipe

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§ 

Cast Iron Pipe §  §  § 

High strength and load bearing capacity Heavy and subjected to internal and external corrosion Lesser strength than ductile iron pipe

§  Ductile Iron Pipe §  §  § 

High resistance to facture and unaffected by extraneous shock and vibration Internal lined with cement Coated externally with bituminous

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§  Galvanised mild steel pipe (BS 1387) §  § 

High tensile strength Black mild steel coated with Zinc

§  Concrete pipe §  §  § 

Strong, durable and corrosion-resistant Smooth interior Heavy

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§  Copper pipe (BS EN 1057) §  §  §  §  § 

Resistance to corrosion Light and easily bend Easy to joint, and concealed in wall Commonly used by contractor for plumbing system Relatively higher material cost

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§  Stainless steel pipe §  §  §  §  § 

A low carbon steel pipe containing chromium and nickel Rigid and harder to bend as compared to copper Good resistance to corrosion Used widely because of its hardness, light and aesthetic appearance High material cost

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§  UPVC pipe (SS 141) § 

Unplasticized polyvinyl chloride §  Resistance to most corrosion §  Light weight §  Pipe can be easily cut, joined and installed §  Not suitable for hot water and exposure to sunlight for long hour §  Lesser strength as compared to steel pipe §  Low resistance to impact load

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Copper pipe (Fig from Crane)

Steel pipe (Fig from Nippon Steel)

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Ductile iron pipe

UPVC pipe (Fig from SNOW)

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n  Choice of piping materials n  Considerations when selecting : n  n  n  n  n  n  n 

Operating fluid pressure Temperature of the fluid Impact of external load Resistance to corrosion, internally and externally No deleterious effect on the water conveyed Ease of installation, exposed and concealed Durability

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n  Method of pipe joining n  Copper pipe n 

Cold method (Compression Joint) §  Non – manipulative (Type A) §  Manipulative (Type B)

n 

Hot method (Brazing or Capillary Joint)

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n  Copper pipe - compression joint n 

Non – manipulative n 

n 

Requires no special preparation. Joints should not be concealed in wall or buried in the ground. For surface fixing or readily accessible space (Example in service duct)

Manipulative type n 

The tube end has to be formed – using special tools. This joint maybe used for underground installation. Fitting must be dezincification resistant

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n  Copper pipe – Brazing

or Capillary Joint n 

The brazing filler rod is fed and drawn by the capillary action into the whole joint.

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n  Methods of jointing UPVC Pipes n  Solvent n  Flange n  Screw and thread n  Welding n  Mechanical rubber rings joint

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n  UPVC pipe – Solvent Joint n 

n  n 

Joints by using jointing solvents. Joints maybe of the spigot and socket type, having socket formed integral with the pipe or alternatively, separate sleeve may be used The internal surfaces of the socket fitting and the pipe end should be degreased with a cleaning agent When joining, ensure that the place is well ventilated. A setting time of this joint is 24 hrs, after the setting time can the pipe be subjected to pressure test

Building Services – Plumbing and Sanitary Services UPVC Pipe – Solvent Joint

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n  Methods of jointing Ductile Iron Pipe n  Flange joint n 

n 

n 

n 

A rigid joint and unlike push-on joint will not absorb longitudinal or lateral movement. Sealed with the aid of gaskets. Used when the place is restricted and pipe can not be rotated or screwed during fixing. Normally used for pump discharge and at meters

Push – on or Rubber ring joint n  n  n 

Used when pipe is laid underground Joint is flexible and tolerance of some deflections Not recommended for pressure pipe, such as pump discharge pipe

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Ductile Iron Pipe : Push-on joint

Building Services – Plumbing and Sanitary Services Flange joint

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Cast Iron Pipe – Hubless Joint

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n  Jointing between dissimilar materials n 

n 

Avoid joining dissimilar materials where possible to avoid electrolytic corrosion (when two or more metals come in the presence of moisture or water, an electric current is created between the metals through the water and as a result, one of the metals will corrode) However, when dissimilar pipes have to be used, there are available approved unions made of electrically nonconducting materials for jointing. For example, copper unions can be used for the following connections: n  n 

Copper pipe and steel pipe Copper pipe and UPVC pipe

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n  Valves n 

Valves are used in piping systems to regulate the flow of fluid. Common types of valve used in building plumbing and sanitary systems are : n  Stop valves §  §  §  §  n 

Gate valve Globe valve Ball valve Butterfly valve

Check valves §  Single check valve §  Double check valve

n  n  n 

Pressure regulating valves Vaccum relief valves Air release valves

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n  Gate valve n  Used for on-off control n  Low resistance to flow when fully open n  Not suitable for controlling flow rate

n  Fig from Toyo

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n  Globe valve n  Used for on/off and throttling operations

n  Fig from Toyo

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n  Ball valve n 

Use for on-off and throttling purposes

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n  Butterfly valve n  Used for isolating and regulating flow

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n  Check valve n  Allow fluid to flow in one direction only n  To prevent backflow

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n  Double check valve n 

n 

Consist of 2 springloaded check valves and an isolating valve at each side Used to prevent backflow

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n  Pressure regulating

valve n 

To regulate the pressure inside pipe to a pre-set level

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n  Vacuum relief valve n  Allow air to enter into the piping system when it is being emptied or subjected to vacuum n  Used to prevent backsiphonage action within the water system

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n  Air release valve n  Allow trapped air in the piping system to escape

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n  Water supply system n  Basically 3 modes of water supply to residential and commercial buildings n 

Direct water supply from PUB main §  Level of highest fitting less than 25 m above mean sea level

n 

Indirect supply through high level storage tank §  Level of highest fitting more than 25 m but less than 37 m above mean sea level

n 

Indirect supply via low level tank to high level tank by water pumps. §  Level of highest fitting more than 37 m above mean sea level

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n  Water tank construction n 

Material n  n  n 

n 

Glass reinforced Polyester (GRP) Stainless steel Reinforced concrete

Associated piping and accessories n  n  n  n  n  n  n  n 

Ball float valve Level indicator Access panel Overflow pipe Warning pipe Vent pipe Drain pipe Cat ladder

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n  Water tank construction n 

n 

n 

Storage tank with storage capacity of more than 5000 litres must be provided with compartments and the necessary pipe work. This is to enable no interruption of water supply during tank cleaning and maintenance Warning pipe of 25mm diameter shall be provided if the storage capacity is 4500 litres and above. Overflow pipe shall be located not less than 50mm below the invert of the overflow pipe and discharge at a conspicuous position The diameter of overflow pipe shall not be less than the inlet pipe diameter.

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n  Security of water storage tanks n  No unauthorised personnel has access to water tanks and its ancillary equipment as well as the premises where these are located n  Storage tanks and its ancillary equipment as well as the premises where these are kept properly locked at all times

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n  Security fence for water

tank

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n  Security fencing for water

tank

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n  Cleaning and sterilization of water tank n  All potable water storage, associated piping and ancillary equipment must be sterilized before use. Sterilization (disinfection) will be accomplished following procedures and requirements of Code of Practice on Water Service (CP : 2005, page 33)

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n  All new water storage tanks shall be sterilized before use. Tank

that has undergone repair work shall also be sterilised n  The sterilisation shall be undertaken by a licensed plumber n  Service pipe should be sterilised together with the mains n  Copy of test results of water samples, certifying that the water is suitable for drinking, shall be submitted to the Authority

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n  Sample of laboratory

result

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n  Prevention of water contamination n  All water service installation for potable drinking water shall be constructed in a manner that will not have any possibility of water contamination or cross-connection with non potable system

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n  Probable causes for water contamination n  n  n  n  n  n  n  n  n  n  n 

Potable pipe installed or laid under waste /soil pipe Waste /soil pipe running above water tank Broken netting for overflow pipe/ warning pipe at water storage tank Damaged tank/tank cover Missing air vent cover Incorrect pipe/fitting Prolonged water stagnation Cross connection Backflow Lack of regular inspection and maintenance Unlocked or damaged security barrier for water tank

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n  Water contamination –

backflow

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n  Water contamination – backflow n 

Caused by back -siphonage

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n  Methods for backflow prevention n  Air gap n 

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n 

n 

Physical separation between a potable and non-potable system by a air space Example : Separation between the tap and the overflow rim of the basin Air gap should be used whenever possible before other types of device is considered

Backflow prevention devices n  n 

Vaccum breaker Double check valve

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n 

Prevention by maintaining an air gap

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Back flow prevention device

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n  Water conservation measures n  The need to conserve water n  n 

n 

Limited water source Water consumption has been rising

Water supply (Singapore) n  n  n 

Imported water – from Malaysia Local water catchment NEWater §  Clean water produced from treating used water by advanced dualmembrane and utraviolet technologies

n 

Desalinated water §  Remove salt content from sea water

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n  Water conservation measures n  Toilets /Washrooms n  n  n 

Install low capacity flushing cisterns 3.5 litres to 4.5 litres) Public toilets need to be fitted with flush valve For non-domestic premises, need to install §  Self-closing delayed-action taps at all wash basins §  Self –closing delayed-action shower taps at shower points §  Constant flow regulators at all wash basin mixers, shower mixer and bib taps

n 

Home Programme §  Water saving bag for water closet cistern §  Thimble for water taps

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n  Water conservation measures n  Other areas n 

Plants §  Use drought resistance plants or plants that fit naturally into the existing climatic conditions and require little irrigation §  Group plants by their water needs such as plants that need high, moderate or little irrigation

n 

Irrigation §  Use recycled water, NEWater or rainwater §  Drip irrigation §  Rain sensor to turn off irrigation system

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Water conservation measures

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Water conservation measures

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n  Sanitary System – Definition of terms n  n 

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n 

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Stack : means a main vertical discharge or venting pipe Ventilating pipe : means a pipe provided to limit the pressure fluctuations within the discharge pipe system Discharge pipe : means a pipe which conveys the discharges from sanitary appliances Depth of seal : means the depth of water which would have to be removed from a fully discharge trap before air could pass freely through the trap Trap means a fitting or part of an appliance or pipe arranged to retain water so as to prevent the passage of foul air

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n 

Sanitary System – Definition of terms (Cont’d) n 

n 

Sanitary plumbing system : means a network or sanitary pipe work above the ground comprises one or more discharge pipes, discharge stack, ventilation pipes, ventilating stacks and fittings for the conveyance of sewage from premises to a sanitary drainage Sanitary drainage system : means a network or underground pipes comprising drain-lines, branch drainlines, fittings and inspection chambers for the conveyance of sewerage within any premises to a sewerage system

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n 

Sanitary System – Definition of terms (Cont’d) n 

Sewerage system : means a system of sewers, pumping station, sewerage treatment plants and treatment works for the collection, treatment and disposal of sewage and recovery of industrial water and include any industrial water main and pipe, drain-line, grease trap, septic tank etc

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n 

Sanitary System – Definition of terms (Cont’d) n 

n 

Waste discharge : means used water not contaminated by soil water or trade effluents , can be taken as the discharge from basins, baths, sinks, drinking fountains, washing machines Soil discharge : means discharge from a soil appliance such as water closets, urinals, and bidets

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n  Traps, vent and water seals n  Traps n 

n 

A trap can be a a fitting or part of an appliance in the case of a water closet pan and arranged to retain water, call the water seal The water seal prevents foul smells from the drains entering the room, the depth of the seal is usually between 50 to 75mm. All traps should be accessible and provided with access cover or cleaning eye to facilitate cleaning

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n  Trap and water seal

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n  Trap Venting n 

n  n  n  n 

A vent is a pipe or opening that brings outside air into the plumbing system and equalizes the pressure on both sides of the trap to prevent trap seal loss A trap provides a water seal that keeps sewer gas from entering the building through a waste outlet It is necessary to design a horizontal drainage pipe to flow half full of waste and half full of air In optimal flow, the pipe will be approximately one-third full of waste with the remaining space occupied by air In the case of vertical pipe, the fluid flow is on the wetted perimeter of the pipe, making the flow look similar to a doughnut

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n  Types of trap n  P trap n  S trap n  Bottle trap

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n  Water seal in a trap can be lost viz : n  n  n  n  n  n  n  n 

Evaporation Self-siphonage Induced siphonage Leakage or mechanical damage Wavering out Momentum Compression Capillary

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Loss of water seal

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n  Types of sanitary plumbing system n 

Single Stack system n 

Non –Ventilated Stack System §  For buildings up to 6 storeys

n 

Ventilated Stack System §  For buildings from 7 to 30 storeys

n 

Fully Ventilated System n 

Two arrangements : §  6 storeys and below §  7 storeys and above

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n  Single Stack System – Non-Ventilated Stack System n  Use where there are single appliances connected to a discharge stack or where the sanitary appliances/ fittings are closely grouped round a discharge stack which is large enough to limit pressure fluctuations without the need for a ventilating stack n  Permit soil and waste water to discharge into a common pipe n  For buildings up to 6 storeys

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n 

Non- ventilated stack system

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n  Single Stack System - Ventilated Stack System n  Requires ventilating stack n  The ventilating stack is also connected to the sanitary drainage system n  Use where there are single appliances connected to a discharge stack or where close grouping of sanitary appliances around the discharge stack n  For buildings from 7 to 30 storeys high n  Traps seals are safeguarded by extending the stack(s) to atmosphere and by cross connecting the ventilating stack

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n 

Ventilated stack system

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n  Fully ventilated system n  Fully ventilated system is used where there are large numbers of sanitary appliance in range or they are widely dispersed n  The system permits the discharges from the soil and waste appliances to be connected into a branch discharge pipe and discharged to a common discharge stack n  The individual soil appliances are individually vented and connected to the main vent stack, which runs side by side to the main discharge stack

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n  Fully ventilated – six storeys and below n  The system uses a separate discharge and ventilating stack, individual traps/soil sanitary appliance is connected directly to the discharge pipe or stack that need to be provided with branch ventilating pipe, which is connected to ventilating stack n  The vent pipe starts at the 2nd level of the building soil appliances, connect to the main stack and terminates to the discharge stack at a point not less than 150mm above the spill over level of topmost soil appliance of floor trap

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n  n 

Fully ventilated system - for six storey or lower

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n  Fully ventilated – seven storeys and above n  The ventilating stack is also connected to the sanitary drainage system

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n  n  n 

Fully ventilated system - for seven storeys or higher

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n  Anti-siphonage pipe and ventilation stack n 

Use of Anti-siphonage Pipes (Ventilating Pipe) is to ventilate the trap in order to :

n 

n 

Prevent the loss of water seals due to induced sighonage and compression Prevent the accumulation of foul gases in the trap

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End of Slides