Testing For Pipe Lines
After laying and joining, the pipeline has to be tested for leakage. Following procedure is adopted for testing. The pipe is slowly charged along with water so in which all air is expelled from the pipe by giving a 25 mm inlet with a stop cock and allowed to stand filled with water for a few days and then tested under pressure. The test pressure is usually 5 kg/cm2 or maximum working pressure plus 50 per cent, whichever is greater. The pressure is applied by means of a manually operated test pump or in case of long pipes, or pipes of large diameter, by a power-driven test pump. The test pump having been stopped, a test pressure will managed itself without measurable loss for at least half an hour. The pipe is tested in sections as the work of laying proceeds. It is preferable to keep the joints exposed for inspection during the testing. An open end of the pipe is temporarily closed for testing under moderate pressure by fitting a watertight expanding plug which is available within the market. The end of the pipe and the plug is secured through struts to resist the end thrust of water pressure in the pipes. Air should not be used for testing water mains. The test should be completed always along with water.