EXAMINATION A. Examine roughing-in for underground fuel storage tanks to verify actual locations. B. Proceed with installation only after unsatisfactory conditions have been corrected. 3.2 EARTHWORK A. Excavate to sufficient depth for a minimum of 36 inches of earth cover from top of tank to finished grade. Extend excavation at least 12 inches around perimeter of tank. B. Backfill excavation per tank manufacturer’s instructions. C. Install filter mat between top of backfill material and earth fill. 3.3 FUEL UST INSTALLATION A. Install in strict accordance with the most recent manufacturer installation instructions, and in accordance with NFPA, PEI/RP100, and authority having jurisdiction. B. Set tie-down eyelets for hold-down straps in concrete-ballast base and tie to reinforcing steel. C. Place 6 inches of clean sand or pea gravel on top of concrete-ballast base. D. Set tank on fill materials and install hold-down straps. E. Connect piping.F. Install tank leak-detection and monitoring devices. G. Install containment sumps. H. Install FRP USTs with FRP hold-down straps, manhole extensions, and manhole risers. I. Test tanks according to Field Quality Control below. 3.4 LABELING AND IDENTIFYING A. Install detectable warning tape directly above UST, 12 inches below finished grade, except 6 inches below subgrade under pavements and slabs. 1. Terminate tracer wire in an accessible area, and identify as "tracer wire" for future use with plastic-laminate sign. 2. Install over edges of each UST. 3.5 FIELD QUALITY CONTROL A. Tanks to be tested in accordance with NFPA 30, 21.5. Subject to approval of the authority having jurisdiction, maintaining the factory interstitial vacuum minimum 5.3” Hg from factory up until completion of backfill may preclude testing according to NFPA 30, 21.5.2.1. 1. Check, document, and report to engineer and authority having jurisdiction the gauge pressure reading upon arrival of tank. 2. Check, document, and report to engineer and authority having jurisdiction the gauge pressure reading upon completion of hoisting tank into position. 3. Check, document, and report to engineer and authority having jurisdiction the gauge pressure reading upon completion of backfill operations. 4. If vacuum is less than min code required 5.3” Hg at any test, then stop installation process at that point and conduct tests in accordance with NFPA 30, 21.5.2.7. B. Perform the following tests and inspections with the assistance of a factory-authorized service representative: 1. Tanks: Minimum hydrostatic or compressed-air test pressures for fuel storage tanks not meeting requirements as above and approval of authority having jurisdiction: a. Double-Wall Tanks: 1) Inner Tanks: Per manufacturer instructions and NFPA 30, 21.5.2.7.1. 2) Interstitial Space: Per manufacturer instructions and NFPA 30, 21.5.2.7.1. b. Where vertical height of fill and vent pipes is such that the static head imposed on the bottom of the tank is greater than 10 psig, hydrostatically test the tank and fill and vent pipes to a pressure equal to the static head thus imposed.
