COMPLIANCE INFO_2006-2008 - Laserfiche WebLink

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Piping system layout Trenching,bedding and backfilling Although fiberglass pipe has excellent strength,it must be protected against impact which may occur from improper handling or during backfilling. • Provide a trench width equal to the pipe diameter plus six inches on each side. Separate multiple lines by at least 4 inches.Refer to Fig.6-1. • Provide a minimum of 18 inches of select backfill between the top of the pipe and unpaved ground surfaces. • Provide a minimum of inches of select backfill between the top of the pipe and reinforced concrete pavement(4 inches minimum thickness). • Provide a minimum of inches of select backfill between the top of the pipe and asphalt pavement(2 inches minimum thickness). • Slope the trench bottom evenly from the dispensers back to sumps or tanks at a minimum'A in/ft of slope.The use of"batter boards"is a very good way to achieve a proper slope. • The trench bottom must be free of hard or sharp objects. • Grade the trench bottom with at least 6 inches of select backfill to provide firm,even support forthe pipe.Compact the subgrade well to prevent differential settling. • Protect the pipe from impact during backfilling and abrasion during operation by surrounding it with a minimum of four inches of select backfill such as washed sand,pea gravel(3/4-inch maximum)or crushed stone(1h-inch maximum). None- .> AWmrc ° P 2(min) ConcreteB 0 4( ) _ 18(min) 4(min) Fig.6-1.Use only select materials for Select back - _ 6(min) bedding and backfilling Dualoy 30001L fuel - handling systems.Native materials are rarely ® suitable and should not be used. JJ' Native 4(min) 6(min) soil Fig.6-2.During layout,bonding and inspection,support the piping on 2x4 blocks to keep the joints clean and to keep bedding out ofthe pipe. 7