Specifications Part 1 - Water Supply, Sewerage and Tube Well Works

3. Water of approved quality for testing shall be arranged by the Contractor.2.7 Testing at siteThe following tests are to be carried out after a new pipe is laid, jointed andpartially back filled. Portions of the line shall be tested by subjecting thepressure test as the laying progresses before the entire line is completed (thetest stretch should be generally exceed 500m), to identify any error ofworkmanship which can be detected and corrected at minimum cost. For allthese tests water of approved quality has to be arranged by the Contractor.2.8 Pressure testPressure test at a pressure of at least double the maximum working pressureshall be carried out. Pipes and joints shall be absolutely water tight under thetest. The procedure for pressure testing shall be as follows:2.8.1 Each valved section of the pipe shall be slowly filled with water and all air shallbe expelled from the pipe through the hydrants and blow offs. If these are notavailable at high places, necessary taping may be made at points of highestelevation before the test is made and plugs inserted after the tests have beencompleted.2.8.2 Sufficient backfill shall be placed on the pipe to resist the movement due topressure while testing. Trench shall be partially backfilled such that the joints,couplings, valves, hydrants or any other fittings shall be left exposed forobservations during testing. The specified pressure based on the elevation ofthe lowest point of the line or section under test and corrected to the elevationof the test gauge, shall be applied by means of a pump not be less than 5minutes.2.9 Leakage testAfter the successful completion of the pressure test. Leakage test shall beconducted at a pressure to be specified by the Engineer for a duration of twohours. The procedure for Leakage test shall be as follows:2.9.1 Leakage is defined as the quantity of water to be supplied into the newly laidpipe, or any valved section thereof, necessary to maintain the specifiedleakage test pressure after the pipe has been filled with water and the airexpelled.2.9.2 No pipe installation shall be accepted until the leakage is less than the numberof cm³/hr. as determined by the following formula:qL =whereqL = the allowable leakage in cm³/hr.N = number of joints in the length of the pipe line.D = diameter of pipe in mm, andP = average test pressure during the leakage testing kg/cm².Urban Administration & Development Department Page 27