SERVICES 1

(ABC007)

Learning Outcome 1

1.1    Explain the variouis water sources and common reticulation systems
The two main water sources are catchment water (catchment area is a protected area generally no buildings here), collected in dams and ground water. Usually dams are at higher elevations and the water is gravity fed to major outlets (reservoirs and then to water towers). Pumps may be needed if the elevation is insufficient. In remote areas the roof is used to collect rainwater for human consumption, and small dams or untreated groundwater is used for normal utilization.
          An intricate pipe network is used in cities for the distribution to the consumer. The primary feeders form the skeleton of the distribution system. Secondary feeders carry large quantities of water to the various areas and from here smaller distribution mains forms a grid over the area to be served. Feeder mains are often looped to reduce shutdowns. The flow in pipes is turbulent and friction losses depend upon the roughness of the pipe, the velocity and the diameter.

1.2    Describe common domestic installations
The supply of water to residential building is usually provided through water towers. They provide a pressure of a minimum of 15 meter head. The Water Corporation installs a water meter and from here the builder is responsible for the domestic installation (see Figure 1).

1.3    State the relevant materials used for the distribution of water throughout installation
There is a large range of piping used for water supply. A variety of materials can be used but according to the BCA (Part 1.2.2) evidence of suitability must be given. The most common materials for pipes are:

·   Cast iron
·   Fibre cement
·   Galvanised iron
·   Copper
·   Plastic
·   Reinforced concrete

However, all piping must comply with the Metropolitan Water Supply, Sewerage, and Drainage Act.

1.4    Explain the necessity for the installation of water storage tanks in buildings relative to the public water supply and reservoir heights &
1.5    Describe how pumps are used to maintain water levels in storage tanks, including single and two stage pumping
As mentioned in 1.2 the Water Corporation provides us with a minimum of 15 meter head. It will be  obvious that no water can be drawn from an outlet at a higher level than the water tower. Therefore multi storey buildings must have storage tanks or a pneumatic or pressurised system to supply water at higher levels. Pumps are used to fill the storage tanks. The pump should not be connected directly to the mains, and break tanks should be installed. The size of the break tank must be correctly designed to prevent stagnation of the water. To ensure a constant supply a second pump is needed for back up. Pumps must be capable to overcome the static lift, friction losses in the pipe work and any other resistance. From the storage tanks the water is gravity fed to the outlets.
         A pneumatic unit incorporates pumps, pressure vessels, air compressor and a control panel usually mounted on a common base. The pump cycle is controlled by the change of air or gas pressure which occur when water is drawn off and subsequently replaced A given volume of water can therefore be removed for a given change in pressure.


1.6    Describe the possible interconnection of water storage tanks for fire protection and the importance of non return valves
In high-rise buildings water storage tanks for normal consumption and storage tanks for fire fighting purposes can be interconnected to provide a sufficient amount of water (flow rate see AS 2419). According to, AS 2118.6 there are two separate storage tanks required, or two mains interconnected, or one main and one on site storage tank. If a swimming pool is found on the top floor of a high-rise building the water is most likely used for fire fighting purposes (an example is Observation City in Scarborough). If water storage tanks for normal consumption and storage tanks for fire fighting purposes are interconnected than a non return valve is required to prevent back-flow into the system and avoid contamination.

Learning Outcome 2

2.1    Explain the location of the Corporation's sewer lines
Main sewer lines are commonly found in the street reserve or at the back of a property boundary. The latter has the advantage the no street crossing is needed for the sewer and the two adjacent properties can be served from the same sewer. The attached plan shows an outline of a combined system. The builder will get a plan with the exact location of the sewer free of charge from the Water Corporation. Flimsy

2.2    State the relevant materials used for sewage and drainage disposal

Materials used are:
·       UPVC (Unplasticised PVC - AS 1260)
·       Polypropylene (used inside the building only, no exposure to sunlight)
·       Cast Iron (AS 1631)
·       Copper ,AS 1432 and Brass AS 1567 (Copper Alloy {copper & zinc})
·       Galvanised Steel (AS1074)
·       Vitrified Clay (AS 1741)
·       Concrete
          All Material must be tested, and when new property sewers are laid, or existing extended, repaired or replaced this work must also be tested and must comply with the Metropolitan Water Supply, Sewerage, and Drainage Act. Three type tests can be applied:
·       Hydrostatic water or smoke to test soundness of joints for leaks.
·       Mirror to check straightness and obstruction.
·       Slide to test alignment of lips and obstructions.

2.3    Describe the characteristics and design criteria for the installation of commonly used traps and plumbing fixtures for both waste and prohibited discharges.
Traps must be installed in drainage and waste systems to prevent the discharge of noxious gases from the sewer through plumbing fixtures into the house. The traps are so designed that an amount of water stays in a U-shaped bend (see Figure blow). Internal traps are those mounted to fixtures inside the building; external traps are fitted to the drainage system outside the building. The formation of sewer gases produces an increase pressure in the system, and to ensure that the water-seal does not break a minimum 75 mm waster-seal is needed. There are a number of ways in which a trap may loose its water-seal. Syphonage is the most common causes of loss of seal in traps, and this can be prevented if vent pipes are used. When fixtures are not used for some time, the water in the trap will gradually evaporate unless the trap is periodically replenished with water. However, loss of seal in traps can be attributed to other causes as well.
          The depositing of prohibited discharges into a property sewer is not allowed. Prohibited discharges are grease, dust, ashes, rubbish, petrol, oil, etc., and special traps are needed to collect these discharges. Also rain- roof- or surface water cannot be discharged into the property sewer.

2.4    Define the term plumbing duct;

          explain the various types of plumbing ducts
Most commercial buildings are designed to have special ducts to house the services. These ducts should be designed to provide easy access for service installation and minimum disruption to other building activities as well as easy access for maintenance and repair. The size, position and quantity, of vertical ducts will depend on the building classification, se and complexity. There are three types of ducts
·            Vertical
·            Horizontal
·            Lateral
            list and describe those items and services that may be housed within plumbing            ducts
          The vertical ducts connecting the various floor levels may house wastewater, fresh water (hot & colt), air conditioning, fire fighting appliances, electrical cables, telephone etc. The size must be large enough to allow an operative to stand inside while attending the services.
          The horizontal duct group generally includes major services ways such as walkways and crawlways and occurs at ground or sub-ground level. These horizontal ducts contain the bulk of the pipe and cable services from the supplier to the consumer. Some buildings like hospitals and factories have horizontal ducts in the basement or below to transfer the services from the various verticals within the building. These walkways have there own lighting system and electrical power points and access is provided at regular interval.
          Lateral distribution of services on each floor may often be via suspended ceilings. There is a variety of ceiling systems available and the most common is panel type that allows easy access to the ceiling void by removing the panels from the suspension framework. Sometimes in commercial buildings there may be one lateral duct on each floor to service both male and female toilets. Both toile areas backing onto the full length of the duct.
          The designer should position the plumbing fixtures in such ways that pipe length is minimised. The services should be concentrated in certain areas.

2.5       Define the roles of:
Hydraulic engineer
          Are not required to all plumbing installation but are mostly engaged in high-rise designs to calculate stresses, friction losses, impact & pressure in relation to water, waste & soil, flow & falls etc. and decide on pipe material & diameters and also the provision of valves & ventilation.
Plumbing consultant
          Should be consulted, preferably at the design stage for all commercial plumbing work. Depending on the complexity of the requirements, s/he may design the entire plumbing concept but is restricted to the extent of works design within high-rise buildings, and a hydraulic engineer may need to be consulted

2.6    Explain the relationship and positioning of Inspection Openings (IO’s) and access ports.
As most pipes and fittings of a house drain are laid underground, provision must be maid for inspection, testing and cleaning of the draining system. There can never be too many IO’s. IO’s for maintenance and inspection must be provided:
·            On each WC or slop hopper  branch
·            At intervals not more than 30 meters
·            At the connection to the Authority’s sewer.
·            At each end of any straight run of drain
·            On inclined jump-ups.
The requirements for maintenance and visual inspection are shown below. Other IO’s may be required in other places by other Sewerage Authorities.

2.7    Explain the method for disposing of sewage from fixtures situated below the level of the Corporation sewer line or the property sewer in  both commercial and domestic situations
Sometimes it is necessary to install plumbing fixtures at levels and locations below the property sewer. The wastes and/or discharges are conveyed to a temporary storage system and then pumped up to and into the property sewer There are two individual types, one for the purposes of all wastes, that is sewage and waste water, and the other for the purposes of waste water only. In both cases pumps are used to raise the waste to the required level.
          Float switches are required to activate a pumps (submersible or outside the collection chamber) to pump sewage out. The attached sketch shows the procedure.

2.8    Discuss septic tanks and soakage systems used in applications other than domestic situations
In areas that are outside a proclaimed sewered area or where connection to a sewage system is impractical, the best alternative is a septic tank system and disposal of the effluent below ground. The septic tank is in fact a mini sewage treatment plant. It is watertight, usually made of concrete, and it treats all household wastewater from bathroom, toilet, kitchen, and laundry. Many residential houses in Perth are still on septic systems. Most systems have two connected cylindrical tanks, concrete tops with inspection openings above both inlets and outlets.
          When wastewater passes through the tanks, heavy solids such as faecial material, food scraps and sands sink to the bottom and form sludge. Light material such as grease, fats and some paper products float to the top and form a scum. Most of the sludge and scum accumulate in the first tank, but some will always carry over to the second tank. Solids are broken down by bacterial action.
          The effluent passes from the second tank into as soil absorption system. All soakage units must be fitted with a flow alteration device irrespective of the soil type and absorptive capacity of that soil. Soakage units are soakwells, leach drains and French drains.
          The control of a septic tank and soakage system installation is the responsibility of the Public Health Department of WA. The septic tank & soakage system or for short aerobic treatment unit is an apparatus for treating sewage either wholly or partially by aerobic means and includes any associated effluent disposal system.

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          Installation of a septic system need the approval of the Health Department

Learning Outcome 3

3.1                Explain the principals of the collection and disposal of rainwater from all type of buildings
Collection of rainwater depends on the amount of rainfall, in litre per minutes onto a roof-catchment area. The rainwater from roof areas is collected in gutters of different shape and material (sizes depend on catchment area). Downpipes (round or rectangular), connected to gutters, convey the rainwater to a lower roof or ground level. If they end onto a lower roof then a spreader should be used.
A direct connection to the storm water drainpipe should be avoided. A graded sump should be used that is connected to the storm-water drain. The storm-water drain runs into a soakwell (soil must have good soakage qualities) or is connected to a storm water drainage system.
*(Secrete gutters should not be used, use other type of flashing)

Commercial buildings have often box gutters with rainwater heads.
They are used as a transition piece to transfer water from a wide gutter to a smaller downpipe of sufficient cross-sectional area.

The waterproof membrane of commercial buildings that have flat roofs is graded towards an internal rainwater sump. The internal sump is joined to a concealed downpipe (housed in a duct or build-in in columns).
Two third of the external wall cladding of high rise buildings is also subjected to rainwater and that should be properly disposed of. For this reason it is not only necessary to have an overhead cover at entrances but also a sufficient drainage around the building.
Material selection for gutters and downpipes is influenced by the amount of salt or atmospheric pollution in the air.

3.2          Discuss the drainage of paved areas and requirements for installing silt pits.
Paved areas must be graded towards an appropriate surface water drainage system to allow the disposal of rainwater. The surface water can be drained into soakwells, usually covered with a cast iron grade (see page 88) or gutters covered with an approved grating.
Paved areas for residential buildings should be a minimum of 50 mm below the floor level and must have a fall away from the building. The area may be drained directly to the garden.
* It is essential that paved areas for commercial purposes are properly drained. If the soil has poor drainage qualities then the storm water should be disposed into a street drainage system. A direct discharge is not allowed and a silt trap must be installed (see page 89). The construction of the silt trap must be in accordance with the Water Corporations drawings and be sized to the requirements of the Corporation.

DECATHLON II puts the lid on surface water drainage, permanently

3.2          Discuss the drainage of paved areas and requirements for installing silt pits.
Paved areas must be graded towards an appropriate surface water drainage system to allow the disposal of rainwater. The surface water can be drained into soakwells, usually covered with a cast iron grade (see page 88) or gutters covered with an approved grating.
Paved areas for residential buildings should be a minimum of 50 mm below the floor level and must have a fall away from the building. The area may be drained directly to the garden.
It is essential that paved areas for commercial purposes are properly drained. If the soil has poor drainage qualities then the storm water should be disposed into a street drainage system. A direct discharge is not allowed and a silt trap must be installed (see page 89) The construction of the silt trap must be in accordance with the Water Corporations drawings and be sized to the requirements of the Corporation.

3.3          Describe the various soakage units according to soil type for disposal of rainwater and from roof and paved areas.
When it rains, some of the rainwater runs off, some is absorbed in the ground, and some of it seeps through the soil until it reaches the water table. The run-off from buildings and paved areas may be drained into stormwater drain or soakwells.
A soakage unit can be a perforated pipe lay in a sub-surface rubble drain filled with aggregates of various sizes, or a prefabricated perforated concrete or PVC unit.
For residential buildings PVC units diameter 600 mm and 900 mm in depth are used for small roof areas. Two down pipes may be connected for each soakage unit in well-drained soil. Lager units must be used for soils with poor drainage qualities. Clay soils, for example, can be more or less impervious and require special care. In such cases lager soakage units or rubble drains are needed. The length and size of rubble drain trenches with perforated pipes, or the size of the soakwell depends on the drainage quality of the soil. For Perth soils prefabricated concrete soakwells usually 1200 mm in diameter and 1200 mm in height, are often used if poorer drainage quality is encountered.


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