BANGLADESH POWER DEVELOPMENT BOARD TENDER ... - BPDB

Trenching for pipes shall be excavated with sufficient width to allow adequateworking space for pipe jointing. Backfilling of trenches to a height 300 mm abovethe top of the pipes using selected materials shall be hand packed and wellrammed against the side of the pipes.The laying of each length of drain is to be commenced at the lower end andsocketed pipes shall be laid with their sockets at the higher end Each pipe is to beaccurately levelled and securely held in position be fore the joint is made.All surface water channels shall be made from concrete grade B as described inSection 17.6.The Contractor shall keep sumps, drains, trenches and ditches free from water atall times until, in the opinion of the Board, the concrete works has hardened.Man-holes, inspection chambers and catch-pits shall be constructed.17.9 Sewage Works17.9.1 GeneralAs there is no existing government central sewage treatment system operating inthe vicinity of the Site, individual septic tanks shall be provided in the Site.17.9.2 Sewer, Manholes And Septic TanksPipes proposed for use in the sewer shall be approved by the Board, cast ironpipes and fittings complying in all respects with B.S.78 and/or B.S.437 shall beused. Manholes or inspection chambers with covers shall be provided at everychange in direction or gradient to satisfy the requirement of the Local Authority.The sewer shall be laid accurately to the design levels and gradient. Each lengthof sewer shall be carefully water tested to the satisfaction of the Board before theconcrete haunching is placed and before the trench is back filled. Septic tanksshall be constructed in accordance with the details shown on the approveddrawings.17.10 Water Reticulation System17.10.1 Internal Water Reticulation SystemThe water supply system shall be designed to serve a dual purpose of providingpotable water for domestic consumption, fire-fighting and plant.17.10.2 Water RequirementThe system shall be designed to meet the project requirement as follows:1. PlumbingThe facilities for general plumbing comprises two (2) deep wells not less than 120m in depth with pump and G.I pipes of appropriate sizes connecting the supply tothe internal plumbing facilities provided for electrical building connection withexisting water supply system at a suitable point. The supply system shall beGhorasal 200 MW to 300 MW Gas Turbine Peaking Power Plant Project (Vol-2 of 3)181