GAIL (India) Limited

83and space left all round the pipes for inspection by the Consultant / Engineer-in-charge. The inside of thesewer must be left absolutely clear in bore and free from cement mortar or other obstructions throughout itentire length, and shall efficiently drain and discharge.III)TESTINGa) All lengths of the sewer drain shall be fully tested for water tightness by means of water pressuremaintained for not less than 30 minutes. Testing shall be carried out from manhole to manhole. All pipesshall be subjected to a test pressure of atleast 1.5 M head of water. The test pressure shall, however, notexceed 6 M head at any point. The pipes shall be plugged preferably with standard design plugs withrubber plugs on both sides. The upper end shall, however, be connected to a pipe for filling with waterand getting the required head poured at one time.b) Sewer lines shall be tested for a straightness by :-i) Inserting a smooth ball 12 mm less than the internal diameter of the pipe.In the absence of obstruction such as yarn or mortar projecting at the joints the ball should roll down theinvert of the pipe and emerge at the lower end.ii)iii)iv)Means of a mirror at one end and a lamp at the other end. If the pipe line is straight the full circle of lightwill be seen otherwise obstructions or deviations will be apparent.The contractor shall give a smoke test to the drain and sewer at his own expense and charges, if directedby the Consultant / Engineer-in-charge.A test register shall be maintained which shall be signed and dated by the Contractor, Consultant/Engineer-in-charge.4.3 MASONRY WORKMasonry work for manhole, chambers, specific tanks and such other works as required shall beconstructed from local best quality bricks in cement mortar 1:5 mix (1 cement: 5 coarse sand) or asspecified in the schedule of quantities All joints shall be properly raked to receive plaster.4.4 TESTINGAll pipes shall be tested to a hydraulic test of 1.5 M head for atleast 30 minutes at the highest point in thesection under test. Test shall be carried out similar to those for stoneware pipes given above. The smoketest shall be carried out by the contractor, if directed by the Consultant, at the expense and charges of thecontractor. A test register shall be maintained which shall be signed and dated by the contractor. Theworks failing during the test have to be redone by the contractor and nothing extra shall be payable to hison this account. The cement wasted in dismantling and redoing works shall be recovered from thecontractor at double the recovery rates4.5 LEAD CAULKED JOINTS FOR C.I. PIPESThe exterior of the socket and exterior of the spigot shall be thoroughly cleaned and dried up. The spigotshall be inserted into the socket right up to the back of the socket and carefully centred by 2 or 3 times ofspun yarn well caulked into the back of the socket. No piece of the yarn shall be shorter than thecircumstance of the pipe The depth of pig lead for various diameters of C.I. pipes and specials shall be asfollows:-Normal sizeof pipe in mm100 mm150 mm200 mm250mmDepth of leadjoint in mm45505050