PIPE LAYING PROCEDURE

A Vision To Clear Solutions.

Laying of mains and pipes on site

            Exaction and killing – The bottoms of the trench excavations shall be carefully prepared so that the barrels of the pipes, when laid, are well bedded for their whole length on a firm surface and are true to line and gradient. The width of the excavation shall be sufficient to allow the pipes to be properly laid and jointed, joints holes being made where necessary.

 In the refilling of the trenches, the pipes shall be surrounded with fine selected   material, well rammed so as to resist subsequent movement of the pipes.

 No stones shall be in contact with the pipes, and when the excavation is in rock, the bottom shall be cut deep enough to permit the pipes to be bedded on a layer of fine selected material, or (especially where there is a steep gradient) on a layer of concrete.

  Preparing Pipes for Laying Underground

The pipes shall be carefully cleared of all foreign matter before being laid. They shall be thoroughly brushed out internally with a well-fitting hard brush, and after laying the open end shall be temporarily plugged to prevent ingress of water, soil, etc, precaution shall be taken to prevent floatation of the plugged pipes, should the trench become flooded.

Any coating, sheathing or wrapping of the pipes shall be examined for damage and repaired, where necessary, and shall also be made continuous over the joints.

            Concrete Pipes and Cast Iron Pipes – Pipes should be laid in accordance with the requirements given in IS: 783-1959* and IS: 3114-1965, respectively.

 Laying Underground Mains

            Where the trench is on a slope, pipe laying shall proceed in and uphill’ direction to facilitate joint making. Except in the case of small pipes under low pressure, thrust blocks of concrete shall be formed at all bends to transmit the hydraulic thrust on to undisturbed ground and to spread it over a sufficient area. Why the hydraulic thrust is in a upward direction, anchor-blocks of sufficient weight shall be provided to which the pipes shall be secured with steel straps. The displacing forces in the mains due to end and radial thrust on bends are given below.

 In the process of installing or repairing any part of a plumbing installation, the finished. Floors, walls, ceilings, tile-work or any other part .of the building or premises, which shall be changed or replaced, shall be left in a safe structural condition in accordance with. All exterior openings provided for the passage of pipe shall be properly sealed. Water service pipes or any underground water pipes shall not be run or laid in the same trench as the building sewer or drainage pipe. Where this is unavoidable, the following conditions shall be fulfilled. The bottom of the water service pipe, at all points, shall be at least 30 cm above the top of the sewer line at its highest point.

 The water service pipe shall be placed on a solid shelf excavated at one side of the common trench. The number of joints in the service pipe shall be kept to a minimum.

The materials and joints of sewer and water service pipe shall be installed in such a manner and shall possess the necessary strength and durability so as to prevent the escape of solids, liquids, and gases there from due to temperature changes, settlement, vibrations and superimposed loads.

 The service pipe shall. Pass into or beneath the building at a depth below the external ground level of not less than O-75 m (provided the foundation is deeper than 0.75 m) and at its point of entry through the structure should be accommodated in a sleeve which should have previously been solidly built in. The space between the pipe and the sleeve shall be filled with bituminous or other suitable material for a minimum length of 15 cm at both ends. Care shall be taken to ensure that before the pipeline is charged all piping and fittings are clean internally, and free from particles of sand or soil, metal fittings chips, etc, which besides causing obstruction& may: lead to failure by corrosion.

 Securing and Supporting of Pipes

            Lead piping of not more than 25 mm bore, in vertical runs, may be secured direct to brick walls (other than external walls) by iron pipe clamps driven into the wall joints, or may be secured to wooden battens or other wood work by iron or brass clips with ears for screw fixing, the clamps or clips or holder bats being at not more than 90 cm intervals. Damage to the piping by the clamps shall be prevented by the insertion of small lead pads. Copper piping shall be secured by copper or copper-alloy clips direct to wood work, or by similar bracket-clips built-in to walls or screwed to plugs. Wrought iron and steel piping shall be secured in a manner similar to that used for copper piping, except that the clips shall be of iron or steel. Plastic pipes should be secured and supported in accordance with the recommendations given in IS: 7634 (Part 2)-1975* and IS: 7634 (Part 3)-19757.

 Spacing of Fixings for Internal Piping

            Fixing on internal pipes shall be spaced at regular intervals as given in Appendix F- IS 2065.