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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 vacuum <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. ) ; 7TYpe <br /> nk Vacuum , Capacity, Duration , <br /> inches Hg gallons hours <br /> • vacuum gauge with a range of 0 inches to 30 <br /> inches Hg graduated in increments of 0. 5 inches Fiberglass 10 20 ,000 1 <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 /> nser(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 integ- <br /> rity test fails. <br /> 7 . When the vacuum level stabilizes , record the <br /> vacuum level and the test start time. <br /> S. 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 />