HYDROSTATIC PRESSURE TEST All newly laid pipe or any valved section thereof should be subjected to hydrostatic pressure of at least 1.5 times the working pressure at the point of testing. TEST PRESSURES SHOULD MEET THE FOLLOWING CRITERIA: Be no less than 1.25 times the working pressure at the highest point along the test section Exceed no pipe, fitting, or thrust-restraint design pressures Be at least two hours in duration Vary by no more than +/- 5 psi (34.5 kPa) for the duration of the test Exceed no more than twice the rated pressure of the valves or hydrants when the pressure boundary of the test section includes closed metal-seated valves or hydrants valves should not be operated in either direction at differential pressure exceeding the rated pressure hydrants in a test section should only be tested with the main valve of the hydrant closed Not exceed the rated pressure of the valves when the pressure boundary of the test section includes closed resilient seated gate valves, or rubber-seated butterfly valves Each valved section of pipe should be slowly filled. The specified test pressure, based on the elevation of the lowest point of the line or section under test and corrected to the elevation of the test gauge, is applied by means of a pump connected to the pipe. Valves should not be operated in either the opening or closing direction at differential pressures above the rated pressure. It is good practice to allow the system to stabilize at the test pressure before conducting the leakage test. Before applying the specified test pressure, air must be completely expelled from the section of the piping being tested. If permanent air vents are not located at all high points, corporation stops shall be installed at such points so that the air can be expelled as the system is filled with water. After all the air has been expelled, the corporation stops are closed and the test pressure applied. At the conclusion of the pressure test, the corporation stops should be removed and plugged or left in place as required by the specifications. Any exposed pipe, fittings, valves, hydrants, and joints should be carefully examined during the pressure test. Any damaged or defective pipe, fittings, valves, or hydrants discovered as the result of the pressure test should be repaired with sound material and the test repeated until satisfactory results are obtained. TESTING ALLOWANCE The testing allowance is defined as the quantity of water that must be supplied (make-up water) to any installed pipeline, or valved section thereof, to maintain pressure within 5 psi 34.5 kPa of the specified test pressure after the air in the pipeline has been expelled and the pipe has been filled with water. The testing allowance is not measured by a drop in pressure in a test section over a period of time. No pipe installation should be accepted if the amount of make-up water is greater than that determined using the following formula: When testing against closed metal seated valves, an additional amount of make-up water per closed valve of 1.2 mL/h/mm of nominal valve size is allowed. When hydrants are in the test section, the test should be made against the main valve in the hydrant. Acceptance of an installation is determined on the basis of the testing allowance. If any test shows an amount of make-up water greater than that allowed, the installer is responsible for locating and repairing any leaks, as necessary, until the test result is within the specified allowance. All visible leaks must be repaired regardless of the amount of leakage.