INSPECTION OF BUILDING DRAINAGE SYSTEM
The following points should be observed for the inspection of building drainage system.
1. The flow through the drains should be observed by opening the inspection chambers, gully traps. 2. If there are any damp spots, they should be detected as the indicated leakages.
3. The water closets, flushing cisterns, traps should be examined.
4. Emission of bad smell if any from the sanitary block should be detected.
5. A detailed survey of the entire system is made and then completely checked.
TESTING OF DRAINAGE SYSTEM
The following are the tests, which commonly employed
(a) Air test: In this test, air is blown into the drain after plugging the ends. This soap solution is then applied. The formation of bubbles indicates leakages.
(b) Hydraulic test or water test: The drain is plugged at the lower inspection chamber and the water is filled under the pressure of 0.015 W/mm". There should not be any visible drop in water level within ten minutes.
(c) Smell Test: Air is mixed with some smelling gas and is allowed to pass through the drainage pipe leaky joints can be detected by smelling.
(d) Colour-water test: Colour water is added from one side. The leakage can be easily seen.
(e) Smoke test: This test is used to detect leakage of rain water pipes and other vertical waste pipes. It this test smoke is forced into the pipe. Leakage can be detected by smell or vision of the smoke through the joint.
MAINTENANCE OF BUILDING DRAINAGE SYSTEM
The house drainage system should be properly maintained and cleaned at regular intervals for its efficient working. The following points should be carefully noted:
(a) Entry of undesired elements: The substance like sand, grit, decayed fruits, pieces of cloth, leaves should not allowed into the sewers and collected separately.
(b) Flushing: In order to maintain the house drainage system in proper working order, it is advisable to flush it once or twice a day.
(c) Inspection: The various units of house drainage system should inspected at regular intervals and damaged pipes/washer of leaky taps should be replaced.
(d) Use of disinfectants: To maintain good sanitary conditions in the building. phenol or disinfectants should be used.