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Recommended Practices for the Testing and Verification of Spill , Overfill , Leak Detection and Secondary Containment Equipment at UST Facilities <br /> sibility of accidentally imposing a high vacuumL <br /> , 77 <br /> that could damage the tank. The use of the valve <br /> is recommended because it limits the vacuum <br /> that can be applied to the interstitial space. ) ; Tank Vacuum , Capacity, Duration , <br /> Type inches Hg gallons hours <br /> • vacuum gauge with a range of 0 inches to 30 < 200000 1 <br /> inches Hg graduated in increments of 0. 5 inches Fiberglass 10 <br /> Hg or less , 20 ,000+ 2 <br /> • toggle valve and vacuum hose ; Steel 6 < 20 ,000 1 <br /> 20,000 + 2 <br /> • stopwatch or other time- measurement device <br /> capable of measuring a 1- second increment; <br /> 4. 2 .9 Pass/Fail Criteria . If there is no loss in <br /> • plumber ' s plug , vacuum level , no liquids are drawn into the inter- <br /> 4 . 2 . 8 Test Procedure. stitial space during the test duration shown in Table <br /> 4 . 1 , and the tank secondary containment area has <br /> 1. Install the plumber ' s plug in the interstitial no additional fluid than at the start of the test , then <br /> riser( s) below any tees . - the tank secondary containment passes the test . <br /> 2 . Connect the vacuum gauge , valve and the If there is any vacuum lost during the test or liquids <br /> vacuum-generating device to the fitting on the are drawn into the interstitial space, then the tank <br /> plumber ' s plug . The valve should be between secondary containment fails the test. <br /> the vacuum source inlet and the pressure <br /> gauge . The gauge should be between the valve <br /> and the fitting so it will read the interstitial vac- <br /> uum when the valve is closed . The automatic <br /> vacuum shutoff valve is located at the inlet of <br /> the vacuum-producing device and should be <br /> set at a minimum of 10 percent and no more <br /> than 2 inches Hg above the test vacuum . <br /> 3 . Ensure all connections are airtight. <br /> 4. Start the vacuum-generating device , and open <br /> the valve . <br /> 5. Pull the vacuum to 10 inches Hg for fiberglass <br /> tanks and 6 inches Hg for steel tanks . Close the <br /> valve . <br /> 6. Allow the vacuum to stabilize for a minimum <br /> of 5 minutes at the specified vacuum level . If <br /> a stable vacuum cannot be maintained , test <br /> equipment shall be inspected for leakage. <br /> Repeat steps 4 and 5 until a stable vacuum is <br /> achieved . If a stable vacuum cannot be main- <br /> tained , the tank secondary containment mteg- <br /> rity test fails . <br /> 7 . When the vacuum level stabilizes , record the <br /> vacuum level and the test start time. <br /> 8. Observe the vacuum level for the period of <br /> time shown in Table 4- 1 . <br /> 9. Record the final time and vacuum level . <br /> 10 . Check the interstitial space for accumulation of <br /> liquids . <br /> pei . org <br />