Specifications Part 1 - Water Supply, Sewerage and Tube Well Works

Sewer jetting machines and gully emptiers are successful and effective also inremoving blockages.14.23.6 When the above methods are not successful or damage to the sewer issuspected, the location of the blockage can be found by the use of sectionalrods from either end of the blocked sewer. Once this is located, the sewerlength near the blockage can be exposed by open excavation to examine andset right the sewer line. Before puncturing the sewer line, foundation concretefor a new manhole is laid and the walls of the manholes are raised to a heightto contain the sewage.14.23.6.1 The sewer is then punctured and the headed up sewage flows down to normal,after which the top of the sewer is completely broken and a channel formed inthe manhole. The sides of the manhole are then raised upto the ground leveland the manhole completed as in normal construction.14.23.7 If the damage to the sewer is extensive and is caused poor foundation then thestretch between the two manholes may have to be relaid on a properfoundation.14.23.8 In the case of a small diameter sewer which is broken to remove the blockage,repair can be affected by using a piece of pipe one size larger than the onebeing repaired. The patch should be the shape of the cut and near the samesize and should be well cemented on with cement mortar.14.24. S.W. Gully Trap :(See Drawing No.- 17)Gully traps shall conform to IS 651. These shall be sound, free from visibledefects such as fire cracks, or hair cracks. The glaze of the traps shall be freefrom crazing. They shall give a sharp clear tone when struck with light hammer.There shall be no broken blisters.Each gully trap shall have one C.I. grating of square size corresponding to thedimensions of inlet of gully trap. It will also have a water tight C.I. cover withframe inside dimensions 300 x 300 mm the cover weighing not less than 4.50Kg and the frame not less than 2.70 Kg. The grating, cover and frame shall beof sound and good casting and shall have truly square machines seating faces.14.25. Fixing S.W. Gully Trap(See Drawing No.-18 & 19)14.25.1 Excavation: The excavation for gully traps shall be done true to dimensions andlevels as indicated on plans or as directed by the Engineer-in-Charge.14.25.2 Fixing: The gully traps shall be fixed on cement concrete foundation 65 cmsquare and not less than 10 cm thick. The mix for the concrete will be 1:5:10 (1cement : 5 fine sand: 10 graded stone aggregate 40 mm nominal size). Thejointing of gully outlet to the branch drain shall be done similar to jointing ofS.W. pipes described above.Urban Administration & Development Department Page 173