Appendix A – Hydrostatic Testing
APPENDI APPENDI X A SECTI ECT I ON 4: HYD HY DROSTA ROSTATI TI C TES TE STI NG EXCERPTED FROM A WWA C600 C600-93
AWWA STAND TA NDARD ARD FOR I NSTAL L ATI ON OF DUCTIL DUCTIL EE-II RON WATER M AI NS AND THEI R APPURTENANCES APPURTENANCES AMERICAN NATIO NATI ONAL STANDARD
Effective ffectivedate: Apr. Apr. 1, 1994. First edition diti on approve approved d byAWWA Board Board of Dir Directors May May 8, 1977. 1977. This This editio ition n approv roved J une 6, 1993. Approved by by American National National Standards Institute I nstitute Fe Feb. 9, 1994. 1994.
AMERICAN WATER WORKS ASSOCIATION
6666 West Quincy Avenue, Denver, Colorado 80235
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Appendix A – Hydrostatic Testing
SECTI ECT I ON 4: HYDRO HY DROS STATI TA TI C TES TE STI NG WARNING: The The testing ing methods describe ibed in this section ion are specific for for
wa water-pr -pressure testing. These procedures should not be applied for air-pressure testing because of the serious safety hazards involved.
Sec. Sec. 4.1 Pre Pr essur ssure e and L eakage T est
4.1.1 Te Test restri restricti ction ons. s. 4.1.1.1 Test pressure shall not be less than 1.25 times the working pressure at the highest point along the test section. 4.1.1.2 Test pressure shall not exceed pipe or thrust-restraint design pressures. 4.1.1.3 The hydrostatic test shall be of at least a 2-h duration. 4.1.1.4 Test pressure shall not vary by more than ±5 psi (34.5 kPa) for the duration of the test. 4.1.1.5 Va V alves shall not be be operated in in ei either directi direction on at a dif differenti rential al pressure pressure exceed exceediing the rated rated val valve worki working pressure. pressure. Use U se of a test test pressure greate greater than the rated valve valve pressure can result result in in trapped test pressure between the gates gates of a doubl double-di e-disc sc gate valve. valve. For For tests at these pressure pressures, s, the test setup should include a provision, independent of the valve, to reduce the line pressure pressure to the rated rated valve valve pressure pressure on completi pletion on of the test. The valve can then be be opened enough to equalize the trappe trapped pressure with with the li line pressure, or fully opened if desired. 4.1.1.6 4.1.1.6 The T he test pressure shall not exceed the rated pressure pressure of the val valves when the the pressure boundary of the test section includes closed, resilient-seated gate valves or butterfly valves. 4.1.2 Pressurization. After ter the pipe pipe has been laid, laid, all all newly wly la laid pi pipe or any any valved valved section thereof shall be subjected to a hydrostatic pressure of at least 1.5 times the working pressure at the point of testing. Each valved section of pipe shall be slowly filled with water, and 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) shal shall be appli pplied by by means ans of a pum pump connected connected to the pipe pipe.. V alves alves shall not be operated in either the opening or closing direction at differential pressures above the rated rated pressure. pressure. It I t is is good practice practice to al allow the system to stabi stabillize at the test pressure before conducting the leakage test. 4.1.3 Ai Air removal. Before appl pplying ying the specif cified test test pressu pressure, re, air shall shall be expel xpelled complete pletely from from the the section section of pipi pi ping ng unde under test. If I f permanent nent air vents are not located at all high points, corporation cocks shall be installed at such points so that the air can be expel xpelled as the line is fi filled with with water. ter. A fter ter all all the air has has been _______________ ______________________ _______________ ________________ _______________ _______________ ________________ _______________ ___________ ____ A-2
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Appendix A – Hydrostatic Testing
expel xpelled, the corporati corporation on cocks shal shall be closed and the test test pressure pressure applie ppli ed. At A t the conclusion of the pressure test, the corporation cocks shall be removed and plugged or left in place as required by the specifications. 4.1.4 Exam xamination tion.. A ll expose xposed pi pipe, fi fittings, valves, ves, hydran hydrants, and and joints oints sha shall be examined careful carefullly during during the the test. Any A ny damage or defective defective pi pipe, fittings ttings,, valve valves, hydrants, or joints that are discovered following the pressure test shall be repaired or replaced with sound material, and the test shall be repeated until satisfactory results results are obtai obtaine ned. 4.1.5 4.1.5 Lea Leakage defined. ned. L eakage shal shall be defined ned as the quantity ntity of water water that must be supplied into the newly laid pipe or any valved section thereof to maintain pressure within 5 psi (34.5 kPa) of the specified test pressure after the pipe has been filled with with water water and and the air has been expelled. L eakage shal shall not be measured by a drop in pressure in a test section over a period of time. 4.1.6 Al Allowabl owable leakage kage. No pi pipe installation tion wil will be accepte ccepted d if the leakage kage is grea greater ter than that determined by the following formula: I n inch inch--poun pound d uni units: L
SD P =
133,200
Where: L = allowa all owable leakage, in in gallons ons per hour hour S = le length ngth of pipe pipe teste tested, d, in feet feet D = nominal dia diameter ter of the pipe pipe, in in inches P = average test pressure pressure during during the the leakage test, in in pounds pounds per per square square inch (gauge (gauge)) I n metric tric uni units: Lm
=
SD P
715,317
Where: Lm S D P
= = = =
allowable owable leakage kage, in litres tres per hour hour length ength of pipe pipe tested, in in metres nominal diam diameter ter of the pipe pipe, in in millimetres average test pressure pressure during during the leakage test, in kPa kPa
The These for formulas las are based on an allow llowable lea leakage of 11.65 gpd/mi/ gpd/mi/iin. (1.079 (1.079 L /day/km/mm /day/km/mm) of nominal diam diameter ter at a pressure of 150 psi (1034 kPa). _______________ ______________________ _______________ ________________ _______________ _______________ ________________ _______________ ___________ ____ Brans Branson on West Design Standar Standards ds for Public ubli c Im I mprovements
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Appendix A – Hydrostatic Testing
4.1.6.1 Al A llowabl owable leakag leakage e at various various press pressure ures s is is shown shown in in Tab Tables 6A and 6B 6B. 4.1.6.2 When testing against closed metal-seated valves, an additional leakage per close closed d valve of 0.007 0.0078 8 ga gal/h/i /h/in. (1.2 mL /h/m /h/mm) of nominal valve valve size size sha shall be allowed. 4.1.6.3 4.1.6.3 Whe When hydrants are are in in the test test section, section, the test shall shall be made ade against the main ain valve valve in in the hydrant. 4.1.7 Accep Accepta tance nce of install nstalla ation. tion. A ccepta cceptance shall be determ termiined on the basis sis of allowabl owable leakag leakage e. I f any test of laid pipe pipe discl disclose oses lea leakage kage grea greater ter than tha that specified in Sec. 4.1.6, repairs or replacements shall be accomplished in accordance with the specifications. 4.1.7.1 Al A ll visi visibl ble e lea leaks are to be be repa repaired rega regardle rdless of the amount ount of leakage kage.
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