12. Plumbing & Drainage Systems
12.1 Description of Systems
Plumbing System
In the plumbing system of T.T.T. Building, the flush water supply is an indirect system which can be separated into three parts: from government main to common main and then to flush water sump tank, from flush water sump tank to flush waetr tank, form flush water tank to W.C. and urinal flushing cistern.
Flush water and potable fresh water are supplied from same government main and the flush water is first stored in the 735 litre fibre-glass flush water sump tank at ground floor. Water is then pumped to 1470 litre R.C. flush water tank at the roof through the main riser. There is a level controller in each of the tanks. If there is inefficient water in the flush water tank, the pump will automatically open to supply water from the flush water sump tank to the flush water tank. However, if there is no water in the sump tank, the pump will not operate, thus protecting the pump. The capacity of the water tank at the roof tank is then drawn to the requried floor when needed. PVC pipes are used for the flushing water system.
Rain Water Drainage System
Rain water is mainly collected on the third floor, roof and upper roof. The surface finish is laid to a fall ( 1 to 80 for the two roof ) to allow rain to flow to the surface channel then to the rain water down pipe. After water goes underground, it passes through several manholes to the last manhole ( terminating manhole ) within the site boundary. Further connection to the storm water manhole is made by the government. The rain water pipe is made of cast iron.
Soil and Waste Disposal System
The soil and waste disposal system and the rain water drainage system are independent. The S&W system is similar to the rain water drainage system except that the waste water is from the roof plant rooms, basins, sinks, W.C. and urinals. There are two cast iron soil and waste stack waste pipes in the design, each with a vent pipe. As the waste water flows underground, it passes through several waste water manholes to the last manhole within the site boundary. Further connection to the government waste water manhole and sewer mains is done by the government.
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