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Rerommended Pra[ti[es fie the Testing and Verification of Spill,therfill,Leak detection and Secondary Containment Equipment at UST Fad Aies "a <br /> . . � a <br /> For tight-wrap tanks, use the test method in this . <br /> CAUTION: Use only an air-operated vacu- section, <br /> um source or a vacuum pump powered by <br /> an explosion-proof motor. Vacuum pumps 4,2.6 Fiberglass Tanks. Determine if the inter- <br /> with electrlc rooters that are not eaplu- sdtial space is a "tight-wrap" design or a "110% � <br /> cion-proof may ignite flammable vapors, containment" design. Either type Df fiberglass tank a <br /> If a portable air compressor i9 used, it may use this test or the latest version of Fiberglass <br /> should be located at ]east 20 feet away Tank&Pipe Institute's (FTPI) RF 2007,Fish Test <br /> from the venturkeductor or outsltle any Protocol far besting the Annular Space of Installed <br /> Class I, Division I area. <br /> iT 9 <br /> 4.2.4 Preparation. The procedures in this see, <br /> tion are general in nature and reflect the suggested <br /> N <br /> vacuum levels and hold times for testing tankt <br /> secondary containment areas, Consult tank mann- '' r <br /> faeturer and aut]tority having jurisdiction (AHJ) <br /> guidelines before performing these tests, as their - <br /> requirements may differ. <br /> - r <br /> 'i. f7 <br /> Determine if there is liquid present in the interst.i- <br /> rial space. If liquid is found, determine if the fluid <br /> is water or product, and remove it to the exrent s.. <br /> practicable. � <br /> FiGU RE 4-3. The vacaurn gauge and contra+valve used <br /> The hydrostatic pressure from a high water table for tank iriterst ref testing, <br /> imposes inward pressure on the outer wall of a <br /> TEST, Applying a vacuum to the interstitial space <br /> of the tank creates additional pressure on the outer <br /> wall. These combined forces can damage the <br /> secondary tank wat] when there is a large defined <br /> spact between the primavy and Secondary tanks. r <br /> Consequently, to prevent darnage to the tank, it is <br /> important to observe the water table and associated � <br /> recommended vacuum levels when testing. + <br /> Vent the primary tank to atmosphere during the <br /> test• - <br /> In some installations, the tank interstitial space <br /> may be vented to minimize the buildup of conden- <br /> sation. In these cases, seal off any vent lines to the <br /> tank interstitial space prior to tesvng. <br /> Determine the volume of the tank. This informa- <br /> tion is available from facility records or the auto- <br /> matic tank gauge(ATG) readout. <br /> 4.2.5 Steel Tanks. Determine if the interstitial <br /> space is a"tight-wrap"design or a"110% contain- <br /> merit" design. Tanks with a 110% containment <br /> design should use the latest version of Steel Tank <br /> Institute's (STI) 80 1.2,,Recommended Practice for <br /> Interstitial 1€ghhicss Testing of Existing Under- FIGURE 44. The lulumber's plug protides a leek-tight <br /> ground Double Wal[Steel Tanks for testing. c nnoct�on to draw a vacuorrt on the tank interstitiaf <br /> space. <br /> pei.org 0 <br />