RFQ023, Annex II - Technical Specifications of water supply.pdf

Technical Specification
ANNEX-II
Testing of the underground water pipes
After laying, jointing and anchoring, the pipe shall be slowly and carefully charged with
water, so that all air is expelled, allowed to stand full for several days and then tested under
pressure.
A long main shall be tested in sections as the work of laying proceeds, and it is an advantage
to leave the joints exposed for inspection during the testing.
The open end of the pipe may be temporarily closed for testing under moderate pressure by
fitting a blank flange. The end of the pipe shall be secured by struts or otherwise, to assist the
end thrust of the water pressure in the pipe.
The test pressure shall be applied by means of manually operated test pump or, in the case of
long pipes or pipes large diameter, by a power-driven test pump, which shall be left
unattended. In either case precautions shall be taken to ensure that the required pressure is not
exceeded. Pressure gauges shall preferably be recalibrated before the test.
1.3.2. Above ground water pipe
Polyvinyl chloride (PVC) pressure pipes, joints and fittings shall comply with TIS-172523, as
fabricated by Siam Pipe Industry Co., Ltd. or equivalents approved, and comply with the
relevant provisions as set out below:
Water Supply: Class PVC 13.5
All PVC pipes and fittings shall be from a single manufacturer and shall be designed,
fabricated, and installed in accordance with the best practices and methods and shall comply
with these Specifications.
Sizes indicated on the Drawings are the nominal sizes.
All PVC pipes and fittings shall be provided with an ultra violet inhibitor.
1.3.3. Pumping system.
Pumping system cover all the pumps set installed in water supply network to process the
system properly and supply water to serve all the buildings inside Correction Center 1 (CC1):
- Transfer pump (TP-01/02) with capacity 2x4 l/s of flow at 15m of head installed at pond
to convey water from pond to treat by injecting alum and passing through slow sand filter
to store at underground treated water tanks.
- Back wash pump (BP-01) with capacity 8 l/s of flow at 30m of head installed at pump
room near the elevated water tank to back wash the slow sand filter in case the sand filter
not in good condition.
- Transfer pump (TP-03/04) with capacity 2x8 l/s of flow at 20m of head installed at pump
room near elevated tank to convey water from underground treated water tanks to elevated
tank to supply to distribution network.
Plumbing Works Page: 4