6.4.2 Laying and Jointing

Before laying the pipes, the detailed map of the area showing the alignment sluice valves scour valvesm, air valves and fire hydrants along with the existing intercepting sewers, telephone and electric cables and gas pipes will have to be studied. Care should be taken to avoid damage to the existing sewer, telephone and electric cables and gas pipes. The Pipe line may be laid on the side of the street where the population is dense. Pipes are laid underground with a cover of 1 meter on the top of the pipe.

Laying of cast iron pipes for water supply purposes has been generally governed by the regulations laid down by the various municipalities and corporations. These regulations are intended to ensure proper laying of pipes giving due consideration to economy and safety workers engaged in laying.

6.4.2.1 EXCAVATION AND PREPARATION OF TRENCH

Excavation may be done by hand or by machine. The trench shall be so dug that pipe may be laid to the required gradient and at the required depth. Whe the pipe line is under a road way a minimum cover of 1.0m is recommended for adoption. The width of the trench at bottom shall provide not less than 200 mm clearance on both sides of the pipe. Additional width shall be provided at positions of sockets and flanges for jointing. Depths of pits at such places shall also be sufficient to permit fininshing of joints.

6.4.2.2 LAYING

While unloading pipes shall not be thrown down but may be unloaded on timber skids. Pipes shall not be dragged along concrete and similar pavements to avoid damage to pipes.

6.4.2.3 DETECTION OF CRACKS IN PIPES

The pipe and fittings shall be inspected for defects and be rung with a light hammer, preferably while susupended, to detect cracks. Smearing the outside with chalk dust helps the location of cracks. If doubt persists further confirmation may be obtained by pouring a little kerosene on the inside of the pipe at the suspected spot. If a crack is present the kerosene seeps through and shows on the outer surface.

Any pipe found unsuitable after inspection before laying shall be rejected.