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i 3 4. EXCAVATION FROM COMPRESSOR PRESSURE RELIEF DEVICE The installing contractor must take all precautions necessary to AIR SUPPLY VALVE protect employees working in or near a tank excavation.These AIR SUPPLY GAUGE RESERVOIR FITTING precautions should include, but are not limited to: SERVICE FITTING •Location and protection of any utility installations near the M excavation before opening the excavation; •Means of securing the walls of the excavation; •Means of preventing exposure of employees to hazardous #` fumes from the excavation; •Protection of employees from hazards associated with water FIGURE 2-4 accumulation in the excavation; •Barricades,etc.to prevent unauthorized vehicle or pedestrian SECONDARY(EXTERNAL)TANK TEST traffic; CAUTION:Do not pressurize the secondary tank(interstitial space) .Inspection of the excavation and surrounding area at least dajly. or the primary tank may rupture and cause tank failure. For additional information on excavation,trenching and shoring t Check the exterior of the tank for monitoring liquid — if liquid is safety practices,consult OSHAs Construction Industry Sttindar8s found,wipe the tank dry and verify that the liquid does not Part 1926,Subpart P. reappear. Lift the tank to check the bottom. Do not roll the tank. The minimum depth of the excavation is normally detefrilfried by DANGER:Do not stand under the tank while it is being lifted. the presence or absence of groundwater and the presence or When the,test is complete, remove the test manifold.Visually absence of traffic at the site.These dimensions are critical to the check the interior of the tank for liquid. Replace the protective successful installation of a tank and are often regulated by code. covers in the service fitting and the reservoir fitting. Refer to: "' x* federal,state and 3. BACKFILL r BEDDING local codes Xerxes tanks must be installed using either pea gravel or crushed •NFPA 30&API 1615 stone which meets the following specifications. •figures 41 to ® J 4-4 below. o 0 GENERAL:The material is washed and free flowing and conforms n brackets s Numberi NOTE: [] s to the specification of ASTM C-33 para.9.1,sizes 6 through 8. No refer umber sa1 more than 5%(by weight)of the material may passthrough a#8 sieve. It is recommended that the supplier certify that the materialDY 6" a conforms to ASTM C-33 and any other applicable specifications. IC36 CONDIT IONS C361 (For additional information, refer to the Xerxes pamphlet Fiberglass Tank Backfill Guidelines.) _ TRAPP1C —_ PEA GRAVEL CRUSHED STONE —�r3/4" 1/2° — 13-1 FIGURE 4-1 Tanks subjected to traffic loads must have a cover depth of at least 18[36]inches of backfill plus 9 inches of asphalt.An acceptable alternative is a minimum of 18[36] inches of backfill plus 6 inches of reinforced concrete. 9 i 6 FIGURE 31 ' FIGURE 3-230 30' =[36' NET 36'. CONDITIONS TRAFFIC PEA GRAVEL:Mix of rountled particles —sizes between 1/8" — I I ' and 3/4". _ — CRUSHED STONE:Mix of angular particles—sizes between 1/8" . NOTE:Numbers in brackets[] and l/2". zrefer to 12'tanks. NOTE:If material which meets these specifications is not available,contact the FIGURE 4-2 Xerxes Technical Service Department for information on approved alternate materials and installation instructions.Using other than approved bedding and back- Tanks subjected t0 traffic loads and high water must have a fill materials without Xerxes'prior written approval will void the tank warranty and may result in tank failure. minimum of 30[36] inches of backfill and either 9 inches of asphalt or 6 inches of reinforced concrete.