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

(iv) No. of slots per m 429(v) % Area of opening at 22.2% inner face17.24.6 Slot size 72.5 x 1.6 mm(i) No. of slots per set 5(ii) No. of sets per row 12(iii) No. of rows per m 13(iv) No. of slots per m 780(v) % Area of opening at 19.2% inner face17.25 Lowering of casing pipe:17.25.1 The lowering and fixing of casing pipe in ordinary tube well and lowering ofcasing assembly in the gravel packed tube wells shall be done in the presenceof authorized representative of the engineer in charge of work.17.25.2 The contractor shall have to ensure that the slotted pipe strainers are loweredat the proper places. The contractor shall see that the joints of the pipes arerigid, water tight and free from kinks. Immediately after lowering the assemblythe contractor shall furnishes a chart showing the aquifers positions in the welland the location ware slotted pipes or strainers are placed.17.25.3 The G. I. casing pipe to be lowered and fixed in intertrappean formation shallbe jointed by welding only. In the case of gravel packed tube well it shall beensured by the contractor that the slotted pipes or screened pipes shall belowered in the tube well at the locations of water bearing aquifers as perdesign. The contractor shall also ensure that joints of the pipes in casingassembly are rigid and water tight and a bail plug is properly fixed in the bottomof casing assembly.17.26 The development of tube well shall be continued during drilling operation. Atthe time of flushing by compressor the discharge from tube well during therecorded on regular intervals for which no separate payment shall be made. Incase of gravel packed tube wells, development by compressor for minimumeight hours after completion of drilling of tube well shall be done and paid for.17.27. The development of ordinary tube wells (other than gravel packed tube well)shall be done by the drilling machines during the drilling operations and noseparate payment for development of such ordinary tube wells shall be made.The development of all type of the tube wells shall be done as per ISspecification (IS 11189-1985)17.28 The tube well shall be disinfected after completion of yield test using bleachingpowder solution as per the direction of Engineer in charge.17.29 The installation of hand pump over the tube well shall be carried out as per ISspecifications IS 15500 (Part 1 to 8) : 2004.Urban Administration & Development Department Page 206