WATER SUPPLY SYSTEM IN LOW-RISE BUILDING

WATER ON EARTH

Figure 1 : Water on Earth (Source: Astronomy Picture of the Day, APOD from NASA)

The blue spheres in the figure above refers to the relative amount of Earth’s water compared to the Earth’s size. Don’t be surprised that these water spheres look so tiny! The largest sphere represents all the water in, on, and above the Earth; the smaller sphere near Kentucky represents Earth’s freshwater in terms of groundwater, swamp water, lakes and rivers. Do you notice the SUPER TINY sphere near Atlanta, Georgia? Yes, it represents our daily usable surface water sources which is the fresh water from all the lakes and rivers. It is an unbelievable fact that only 0.03 % of total global water is usable for our daily life!

There are two main sources of water: surface water and ground water. Surface water can be found in lakes, rivers, and reservoirs; while ground water lies under the surface of land, where t travels through and fills the openings in rocks (rocks that can store and transmit underground water are called as aquifers). With this little amount of water, yet water is still contaminated by dissolved gasses, suspended solids, biological components, dissolved organics and minerals via 4 main sources of water contamination: Chemical reaction, Biological reaction, Ecological activities and Human activities. 

Figure 2: Overview of World Water Supply System ( Source: UNDP. Data as of 2006)

There are countries around the world which the people there are lacking of clean water. We should be really grateful that we can actually have clean water for safe drinking. Contaminated water has to go through a series of purification process before becoming the clean water we obtain from our taps at home.

Figure 3 : Water Treatment Process (Source: Ir. Abdul Aziz Abas, Technical Director at Jacobs Engineering Group Malaysia)

Process of removing contaminants might varies from regions to regions, however there are a few crucial steps which are indispensable. Aeration: raw water enters an aerator which creates sufficient turbulence to achieve a dissolved oxygen content of 80% saturation at ambient temperature ; Sedimentation : water move slowly so that the heavy 'floc' particles will settle down and deposit on the bottom of the basin; Filtration: water flows through a filter made of many layers of sand, gravel and crushed anthracite, collecting impurities and bacteria in the water; Sterilization: the water is disinfected to destroy any disease-causing bacteria, viruses, and parasites using effective disinfectant (chlorine) before progress to distribution system. 

After various processes of purification and removing contaminants, water finally reach our homes! Have you ever wondered why is there ALWAYS water coming out from the tap? Let’s reveal it now!

Figure 4: Why is there ALWAYS water coming out from the tap? (Source: WLRN Miami, South Florida)

 WATER SUPPLY SYSTEM

Figure 5: Example of building water supply system (Source: Vodovod Kanalizacija)

Building water supply system is a series of pipes, pumps, control devices and equipment that delivers water of suitable quality, amount and pressure to consumer. It includes the traditional way of manual operation by rivers and wells, as well as its advanced installation in either low-rise or high-rise buildings. Water supply system is further divided into hot and cold water supply system.

Cold water system basically provides water for a few purposes, such as drinking, cooking, washing and sanitary. There are two types of cold water supply systems in low rise buildings, namely the direct and indirect supply system.

Figure 6 : Cold water direct supply system

DIRECT SUPPLY SYSTEM

In direct system, water is delivered directly from the mains to fixtures at various floors with required pressure. Normally, water for drinking and cooking purposes is directly supplied using this system as the water that goes through storage tank might be contaminated. There are separate connections to be provided for domestic and non-domestic requirement. This system is cheaper and easier to be installed as it eliminates extra costs of pumps and tanks. Chances for bacterial contamination are further be reduced thus provides us with safe drinking water. However, this is only useful for the building which is not more than two floors. Not to forget that this system is comparatively noisier due to its higher water pressure. Water supply might get affected during peak load hour as well.

Figure 7 : Cold water indirect supply system

INDIRECT SUPPLY SYSTEM

Water goes to the overhead tank and then be redistributed to fixtures at different floor by gravity in indirect supply system. This is commonly ordinary domestic purposes and necessarily employed in isolated work and where municipal service is available. All the plumbing fixtures are supplied with water directly from the tank and are therefore subjected to a constant minimum pressure depending on their distance below the tank. Water tank storage has advantages of its uniform pressure, also minimises expense of fittings and maintaining low-pressure work. The large capacity of cistern provides a reserve of water during water supply disruption.

CASE BUILDING

Figure 8 : Pusat Kesihatan Universiti Teknologi Malaysia (PKU-UTM)

Our case building is Pusat Kesihatan Universiti Teknologi Malaysia (PKU-UTM). It is one of the examples using indirect water supply system as shown in the floor plan below. Water from the mains goes to the tank first before redistributed to other fixtures. Despite, water for drinking purposes is still directly supplied from the mains. 

Figure 9: Part of Pusat Kesihatan UTM Floor Plan with piping indication (Source: Raw Floor Plan from Pejabat Harta Bina UTM)

PARTS OF WATER DISTRIBUTION

Figure 10 :Boundary of water pipes (Source: DC Water and Sewer Authority)

Service pipe

The pipe from the main or other source of potable water supply to the water distribution system of the building served.

Figure 11: Service pipe comprises of communication pipe and supply pipe (Source: Roll On Friday)

Figure 12 : Communication pipe at PKU -UTM

Communication pipe

Communication pipes carry water between the water mains and the boundary of private property.

Figure 13 : Distribution pipe at PKU -UTM

Distribution pipe/ supply pipe

A pipe within the structure or on the premises which conveys water from the water service pipe to the point of utilization

Figure 14: Water Tank at PKU -UTM

Water tank

Water tanks are used to provide storage of water for use in many applications. Ventilation cap is provided to avoid the entry of insects.  

Figure 15 : Riser Pipe at PKU -UTM

Riser pipe

Riser is a vertical metal or plastic supply line that connects a faucet or shower fixture to the water supply stop valve.

Figure 16 : Fire Hydrant at PKU - UTM

Fire Hydrant

In buildings, there may be separated or combined water connections for fire hydrant system and domestic water supplies.

EXTRA INFORMATION~ PIPES MATERIALS

A water pipe is any pipe or tube designed to transport treated drinking water to consumers. They differ according to size:

          ●        Large diameter main pipe (which supply entire town)

          ●        Smaller branch lines that supply a street or group of building

          ●        Smaller diameter pipes located within individual building

We will look at the following types of plumbing materials used in piping for waste lines, water supply pipes, and natural gas supply:

●        PVC (Poly0Vinyl Chloride) for plumbing waste lines

●        Galvanized iron for water supply lines

●        Copper (rigid and flexible) for water supply lines

●        CPVC (Chlorinated Poly-Vinyl Chloride) for water supply lines

●        PEX (Cross-linked Polyethylene) for water supply lines

1)     CPVC

CPVC stands for ​chlorinated polyvinyl chloride. It is often (but not always) a cream-colored or off-white plastic. This type of pipe can stand temperatures up to about 180 F (this depends on the schedule), so it and can be used for hot and cold water.

Prevalent Use: CPVC is used for hot and cold water supply piping.

Advantages of CPVC pipes:

●        Light in weight, tough, resistant to chemical attack and available in large lengths depends on weather and place.

●        The plastic pipes can reduce the cost of handling, transportation and installation.

●        Smooth internal surface of the pipes offers less friction.

Disadvantages of CPVC pipes:

●        They are not installed in high temperature.

2)    PVC

PVC stand for polyvinyl chloride. It is most commonly used for irrigation piping, home, and building supply piping. PVC is normally used for cold water pipes only.

Prevalent Use: Use for sanitary waste lines, vent pipes, and drain traps.
Advantages of PVC pipes:

• PVC pressure pipes are designed theoretically for 50 years but it can last more than 100 years.
• Long term durability and higher resistance
• Excellent resistance to bacteria

Disadvantages of PVC pipes: 

• They cannot be used at high temperature
• PVC pipes do not have the same strength as cast-iron or galvanized irons pipes

3)    PEX

     

PEX stands for cross-linked polyethylene or XLPEl. PEX is commonly used for hot and cold water in homes, and for hydronic heating systems (such as radiant under-floor systems) due to its resistance to hot and cold temperatures. PEX is widely used now for its competitive pricing, ease of use, and the long rolls of piping that it can come in.

Prevalent Use: Water supply and radiant heating pipe

Advantages of PEX:

●        Flexibility enables it to bend around most corners without coupling or fitting.

●        More resistant to bursts.

●        It can withstand extreme temperatures ,creep deformation and chemical attack.

Disadvantages of PEX:

●        The pipe impermeable membrane makes it vulnerable to water contamination.

●        They are susceptible to damage by the sun ultraviolet rays.

4)    Copper Pipe (Rigid & Flexible)

This type of pipe is mostly used for hot and cold water distribution, as well as being regularly used in HVAC systems for refrigerant lines. Copper piping works in both underground and above-ground applications, but copper can be affected by some soils and should be sleeved if used underground.

Prevalent Use: Rigid copper pipes are used for longer runs of water supply, and in some cases as waste lines in the home. Flexible copper is used in short runs, for water supply, and for the water supply tubing for refrigerators and dishwashers. Copper may also be used for gas piping. 

Advantages of cooper pipes:

●        Naturally corrosion-resistant metal.

●        Cooper pipes is also lightweight and easy to carry.

●        Easier to extend over stretcher.

Disadvantages of cooper pipes:

●        The cost of cooper pipes more than plastic pipes.

●        They are not good to install for plumbing systems that draw water from a well.

5)    Galvanized Pipe

Galvanized pipe steel or iron pipe that has been galvanized with a zinc coating. This galvanized coating keeps the water from corroding the pipe. Because of the amount of work that goes into cutting, threading, and installing galvanized pipe, it is rarely used in homes except for limited use in repairs. Galvanized pipe is still considered a safe transport for drinking water and is still seen in larger commercial applications for water distribution.

Prevalent Use: Water supply lines and drain lines in older homes.
Advantages of iron pipes:

• Able to withstand high water pressure well
• Stronger and rugged durable

Disadvantages of iron pipes:

• No resistant to corrosion and scaling with certain types of water
• Not recommended for underground usage

PEEKABOO ~ NEXT WEEK WE'LL BE UPDATING YOU ALLS ON WATER SUPPLY SYSTEM IN HIGH-RISE BUILDINGS AND BASIC SANITARY SYSTEMS!

DON'T MISS THE CHANCE TO KNOW HOW IS YOUR 'DAILY BUSINESS' DISCHARGED FROM THE BUILDING!