COLD WATER SUPPLY SYSTEM (PART 2)

Subject: Building Services 1 [ BLD 60403]

LECTURE OVERVIEW

1. Water supply to high rise building

2. Materials for piping

3. Piping and fitting sizing of cold water pipes

4. Sanitary appliances

5. Sanitary appliances for disabled people

1. Water supply to high rise building

Pneumatic Cylinder System

How does it works:

1. Compressed air in the cylinder forces water up to the float valves and drinking water outlets on the upper floor.

2. As the cylinder empties a low pressure switch engages the duty pump.

3. When the pump has refilled the cylinder, a high pressure switch disengages the pump.

4. In the same time, some air is absorbed by the water.

Pneumatic Cylinder System

5. A float switch detects the high water level in the cylinder and activates an air compressor to regulate the correct volume of air.

6. Break pressure cisterns supply from the storage cisterns at the roof level or from the rising main.

2. Material for Piping

PIPE MATERIALS:-

• COPPER

• PLASTIC

• CAST IRON

• CONCRETE

• STEEL

• GALVANISED STEEL

Materials:-

• Suitability.

• Fit for purpose – no adverse affect on the health and safety of the building.

• Consult water supplier at an early stage.

• Check the character of the water supply and ground conditions.

• Some water are aggressive to certain type of soils.

• Water consultant able to advise on local conditions.

Continued:-

• Dissimilar pipe materials should not be connected together.

• Temperature limits for pipes and fittings:-

oCold water installation – 40ºC Degree Celsius.

oHot water installation - 95ºC Degree Celsius.

• Installation should be capable of operating effectively.

Factors affecting choices of materials

1. Effect on water quality

2. Cost, service life and maintenance needs

3. Internal and external corrosion

4. Compatibility of materials

5. Temperature effect. (Plastic)

6. Vibration, stress

7. Internal water pressure.

Copper pipes

• Found at specially constructed service ducts.

• by forming joints and bronze welding them

• specially manufactured brazing fitting

Advantages and Disadvantages of copper pipes

Soft metal, easy to bend.

Installed using less fasteners and connectors

Less hardware used, easier to install.

× Expensive compare with plastic.

× Only suitable for water that has a PH between 6.5 to 8.5. Water come from well may be too acidic.

Plastic pipes

• Widely used for domestic water supply and drainage, waste and vent pipe.

• Polyvinyl chloride (PVC)

• Chlorinated polyvinyl chloride (CPVC)

• Polypropylene (PP)

• Polybutlyene (PB)

• Polyethylene (PE)

• Malaysia Standard Code of Practice for the installation of Piping System and Appliances.

Polyvinyl chloride (PVC) & Chlorinated polyvinyl chloride (CPVC)

• Rigid plastic pipes similar to PVC drain pipes.

• With thicker walls to deal with water pressure

• PVC can be used for cold water only or for ventilation.

• CPVC can be used for hot and cold potable water supply

• Connection – primers and solvent cements are required by code.

PVC & CPVC Pipes

PBT -Polybutylene Terephthalate

• Flexible plastic pipe.

• Attached to barbed fitting.

• Secured in place with copper crimp ring.

PEX - Cross-linked polyethylene

• Mechanically joined fittings.

• Employing barbs and crimped steel or copper fittings.

PEX Aqua – PEX-AL-PEX

• Aluminum sandwich.

• Aluminum pipe sandwiched between layers of PEX and connected with brass compression fittings.

Poly Tanks

• Plastic polyethylene cisterns.

• Underground water tanks, above ground water tanks.

• Made of linear polyethylene

• Suitable as potable water storage tank.

Advantages and Disadvantages of plastic pipe

Light weight, tough, resistant to chemical attack.

Available in large lengths.

Reduce cost of handling, transportation and installation.

Less number of joints facilitate the speed and reduced chances of leakage.

Rust resistant, good elastic properties.

Their adaptability to earth movements.

Smooth internal surface of the pipes offer less friction, it saves the energy in the conveyance of water.

Non-decomposing.

Advantages and Disadvantages of plastic pipe

×Plastic pipes are not installed in high temperature.

×Easily cracked.

×At higher temperatures, the strength of plastic pipes reduces.

Other pipes

• Galvanized iron pipe is a pipe commonly used for potable water and sewage distribution.

• Better pipe materials for underground pipes.

• Stronger and more fracture resistant.

3. Piping and fitting sizing of cold water pipes

Pipe standard BS EN 1057

Malaysia Standard Code MS

• Malaysian Standard MS 1058 (PE pipe and fittings) MS 1063 (PVC pipes) etc.

Standard Pipe Size Schedule

Graphical Symbols for Pipe Fittings

Problem occurs to pipe

• Loss of seal – when a full-bore flow occurs in a main branch discharge pipe, creating a negative pressure in the discharge pipe from the trap.

Loss of seal caused by - Siphonage

1. Self siphonage – as an appliance discharges, the water fill the waste pipe and create a vacuum to draw out the seal.

2. Induced siphonage – the discharge from one appliance draws out the seal in the trap of an adjacent appliance by creating a vacuum in that appliance’s branch pipe.

Self Siphonage

Loss of seal caused by – Back pressure, Capillary action, Wavering out

3. Back pressure – compression occurs due to resistance to flow at the base of a stack. The positive pressure displaces water in the lowest trap.

Loss of seal caused by – Back pressure, Capillary action, Wavering out

4. Capillary action – a piece of rag, string or hair caught on the trap outlet.

5. Wavering out – gusts of wind blowing over the top of the stack can cause a partial vacuum to disturb water seals.

Capillary action Wavering out

To overcome loss of seal problem

• A separate pipe of smaller diameter is attached to the traps, which connects the trap to the vent pipe.

• This pipe is known as anti-siphonage pipe.

• It supplies air to the short branch pipe of the lower fixture, at the time of suction, otherwise it acts as a vent pipe of the lower fixtures.

4. Sanitary Appliances

5. Sanitary appliances for disabled people

5. Sanitary appliances for disabled people • Facilities for disabled people should be provided

within conventional separate sex WC and washroom compartment.

• A suitable compartment contain some appliances fitted with support rails

• Sufficient space to accommodate persons with impaired leg movement and with crutches

• Compartment door opens outwards.

A disabled toilet should have:-

• An emergency release device, operated from the outside

• A horizontal bar for closing, fitted to the inside.

• Passageway width, minimum 1200mm, WC compartment size, minimum 2200x1500mm

• Door into compartment, minimum 1000mm clear width.

• Support/grab rails of 50mm minimum diameter, each side of a wash basin.

• Hinged or drop-drown rail at least 300mm long on the exposed side of a WC.

• WC positioned to allow lateral transfer from a wheelchair.

• WC seat of rigid and robust material, set to a height of 480mm above finished floor level.

• Means for flushing, maximum 1200mm above finished floor level.

• Wash basin height maximum 750mm and reachable whilst seated on WC pan.

• Wash basin taps of the quarter turn lever type, or an electric sensor operated discharge. Water temperature at 35 degree Celsius maximum.

• Emergency alarm cord suspended from the ceiling, as close as possible to a wall.

Thank You

CHILDREN ARE QUICK AND ALWAYS SPEAK THEIR MINDS

Teacher: Donald, what is the chemical formula for water?

Donald: H I J K L M N O. Teacher: what are you talking about?

Donald: Yesterday you said it’s H to O.