COMPLIANCE INFO_1996-2006 - Laserfiche WebLink

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E reading. Inspect for leaks by monitoring both gauges for any fluctuations in pressure. If no leaks are detected, release pressure on Lviks by First releasing the air on the interstice. Once air has completely exhausted from the interstice, then release pressure in the primary tank. Refer to the PEI/RP-100 for additional comments. Vacuum Testing of Double Wall Tanks (Type I Construction Only) Some Modem Welding Company Double Wall tanks are shipped with a vacuum between the interstice and primary tank. When a tank is shipped in this manner it is not subject to the air/soap testing method as described earlier. This is provided the tank arrives at the installation site within the following vacuum limits. Tanks shipped under vacuum from Modem Welding Company facilities shall have a vacuum reading of at least 8" Hg. NFPA-30 states that a vacuum of at least 5.3" Hg must be maintained for one hour to confirm tank's tightness. If this minimum vacuum is maintained for one hour, both the inner and outer tank are considered properly tested. Small fluctuations in interstice vacuum are caused by temperature, elevation and barometric pressure changes. It is required that the customer or customer's representathm confirm and sign off on Modem Welding Company's "Bill 49 F-ading" in the presence of delivering driver, that the tank I received at jobsite with the noted vacuum reading. Vacu- # 0 0 - - I b -.IT =-t i Jacketed, secondarily contained underground tanks are shipped with a vacuum between the interstice and primary tank. When a tank is shipped in this manner it is not subject to the air/soap testing method as described earlier. This is provided the tank arrives at the installation site within the following vacuum limits. Tanks shipped from Modem Welding Company facilities shall have a minimum vacuum reading of at least 8" Hg. NFPA-30 states that a vacuum of at least 5.3" Hg must be maintained for one hour to confirm tanles tightness. if this minimum vacuum is maintained for one hour, both the inner and outer tank are considered properly tested. Small fluctuations in interstice vacuum are caused by temperature, elevation and barometric pressure changes. It is required that the customer or customer's representative confirm and sign off on Modem Welding Company's "Bill of Lading" in the presence of delivering driver, that the tank was received at jobsite with the noted vacuum reading. Vacuum readings at time of delivery and just before the tank is covered up must be noted on the installation checklist to implement the warranty of the tank. BACKFILL AND BEDDING REQUIREMENTS Acceptable materials of backfill and bedding are: a. Clean sand which is graded, well granulated, free flowing, non corrosive and inert. Sand must be able to be compacted to 85% compaction density for proper structural support of tank. b. Crushed rock which is well graded, granulated, free flowing, non corrosive and inert. Angular particle size must be no smaller than 1/8" and no larger than 1/2". c. Pea Gravel must be clean, naturally rounded, free flowing, non corrosive and inert, Angular particle size must be no smaller thari 1/8" and no larger than 3/4". All materials must be free of ice and snow when used as backfill material. Crushed rock and pea gravel shall have no more than 3% (by weight) of the material pass through a #8 sieve. Whichever of the three materials used for your excavation, a 85% compaction rate must be achieved. I