In this article we will discuss about the hydrostatic and leakage tests performed for newly laid pipes.
Hydrostatic Test:
After laying the new pipe line, jointing and back filling, it is subjected to the following tests:
(i) Pressure test at a pressure of at least double the maximum working pressure-pipe and joints shall be absolutely watertight under the test.
(ii) Leakage test (to be conducted after the satisfactory completion of the pressure test) at a pressure to be specified by the authority for a duration of two hours.
ADVERTISEMENTS:
During the laying of pipe line, its hydrostatic test is done in parts. In this way any error of workmanship will be found immediately and can be rectified at the minimum cost. Usually the length of the section to be tested is kept up to 500 m.
Leakage Test:
Leakage is defined as the quantity of water to be supplied into the newly laid pipe, or any valved section there of necessary to maintain the specified leakage test pressure after the pipe has been filled with water and the air is expelled.
No pipe line is found to be satisfactory, until the leakage is less than the number of cm2/ h as determined by the following formula:
Q = ND √P/3.3
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Where, Q = allowable leakage in cm2/h
N = Number of joints in the length of the pipe line
D = pipe diameter in mm
P = the average test pressure during the leakage test in kg/cm2.