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0 • <br /> 3. BACKFILL AND BEDDING Refer to: <br /> ® �! <br /> Xerxes tanks must be installed using either pea gravel or crushed •federal,state and local <br /> codes 6 <br /> • stone which meets the following specifications. •NFPA 30&API 1615 <br /> GENERAL:The material is washed,free flowing and free of • figures 4-1 to 4-4 below. <br /> ice,snow and debris. It conforms to the specification of ASTM [36'[ 6 <br /> NOTE:Numbers in brackets[] coNOIRn oNs [367 <br /> C-33 par.9.1,sizes 6 through 8.No more than 5%(by weight)of refer t:Nu foot tanks. <br /> the material may pass through a#8 sieve. It is recommended that TRAFFIC <br /> the supplier certify that the material conforms to ASTM C-33 and <br /> any other applicable specifications.(For additional information, z" <br /> refer to the Xerxes pamphlet Fiberglass Tank Backfill Guidelines.) = — <br /> FIGURE 4-1 <br /> PEA GRAVEL CRUSHED STONE Tanks subjected to traffic loads must have a cover depth of at <br /> 1 iz" least 18[36]inches of backfill plus 9 inches of asphalt.An <br /> 3/4" acceptable alternative is a minimum of 18 36 Inches of backfill <br /> �{ plus 6 inches of reinforced concrete. <br /> ® � ® NOTE:Numbers in brackets[] <br /> 9" ° 6" refer tol2 foot tanks. <br /> 30" NET [36"] <br /> —[36] CONDITIONS <br /> TRAFFIC <br /> FIGURE 3-1 FIGURE 3-2 _ — <br /> iz"_ <br /> PEA GRAVEL:Mix of rounded particles-sizes between 1/8"and <br /> 3/4". FIGURE 4-2 <br /> CRUSHED STONE:Mix of angular particles-sizes between 1/8" Tanks subjected to traffic loads and high water must have a <br /> • and 1/2". minimum of 30[36]inches of backfill and either 9 inches of <br /> NOTE:If material which meets these specifications is not available,contact the asphalt or 6 inches of reinforced concrete. <br /> Xerxes Technical Service Department for information on approved alternate <br /> materials and installation instructions.Using other than approved bedding and NOTE:Numbers in brackets[] <br /> backfill materials without Xerxes prior written approval will void the tank warranty refer to 12 foot tanks. <br /> and may result in tank failure. 4- <br /> 4.-EXCAVATION PARAMETERS [487 DRV 12 <br /> CONDITIONS [367 <br /> The installing contractor must take all precautions necessary to RAFIC <br /> protect employees working in or near a tank excavation.These <br /> precautions should include,but are not limited to: <br /> • Location and protection of any utility installations near the 2 <br /> excavation before opening the excavation; FIGURE 4-3 <br /> • Means of securing the walls of the excavation; Tanks not subjected to traffic loads must have a minimum cover <br /> • Means of preventing exposure of employees to hazardous depth of 24[48]inches of backfill,or 12[36]inches of backfill plus <br /> fumes from the excavation; 4 inches of reinforced concrete or 6 inches of asphalt. <br /> • Protection of employees from hazards associated with water <br /> accumulation in the excavation; <br /> • Barricades,etc.to prevent unauthorized vehicle or NOTE:Numbers in brackets[j <br /> pedestrian traffic; refer to 12 foot tanks. <br /> • Inspection of the excavation and surrounding area at[east <br /> daily. 36 <br /> [487 VET <br /> CONDIilON6 <br /> For additional information on excavation,trenching and shoring <br /> NO <br /> safety practices,consult OSHA's Construction Industry Standards RAFFIC <br /> Part 1926,Subpart P. <br /> The minimum depth of the excavation is normally determined by — 12- <br /> • the presence or absence of groundwater and the presence or <br /> absence of traffic at the site.These dimensions are critical to the FIGURE 4-4 <br /> successful installation of a tank and are often regulated by code. Tanks in high water areas not subjected to traffic loads must have <br /> a minimum of 36[48]inches of backfill covering. <br />