Laserfiche WebLink
5 Trenching' bedding <br />RECOMMENDED PRACTICES <br />and backfilling <br />Although fiberglass pipe has excellent strength, it must be protected against impact <br />which may occur from improper handling or during backfilling. <br />• Provide a trench width equal to the pipe diameter plus six inches on each side. <br />Separate multiple lines by at least 4 inches. Refer to Fig. 5-1. <br />• Provide a minimum of 18 inches of select backfill between the top of the pipe <br />►' <br />and unpaved ground surfaces. <br />• Provide a minimum of 4 inches of select backfill between the top of the pipe and <br />reinforced concrete pavement (4 inches minimum thickness). <br />• Provide a minimum of 8 inches of select backfill between the top of the pipe and <br />^.� <br />asphalt pavement (2 inches minimum thickness). <br />y• <br />Slope the trench bottom evenly from the dispensers back to sumps or tanks at a <br />RECDEIVED <br />minimum's in/ft. <br />JUL1 1 <br />• Maintain the trench bottom free of hard or sharp objects. <br />• Grade the trench bottom with at least 6 inches of select backfill to provide firm, <br />ENVIRONMENTAL HEALTH <br />even support for the pipe. Compact the subgrade well to prevent differential <br />PERMIT / SERVICES <br />settling. <br />• Protect the pipe from impact during backfilling and abrasion during operation by <br />surrounding it with four to six inches of select backfill such as washed sand, pea <br />gravel (3/4-inch maximum) or crushed stone (1h-inch maximum).' <br />• Wrap pipe lying near concrete with rubber or foam padding to avoid direct <br />contact with the concrete. <br />IF""" <br />Fig. 5-1. Use only select materials <br />for bedding and backfilling <br />Dualoy 3000/L fuel handling <br />systems. Native materials <br />are rarely suitable and <br />should not be used. <br />6 Dry fitting contained <br />primary piping <br />(i <br />Fig. 6-1. During layout, bonding <br />and inspection, support the piping <br />on 2x4 blocks to keep the joints <br />clean and to keep bedding <br />out of the pipe. <br />None <br />Asphalt 2 (min) <br />Concrete <br />4 (min) 18 (min) <br />o ,zl, o .� <br />8 (min) <br />4 (min) O O O <br />6 (min) <br />Native — ---- <br />soil%/����«i — -- <br />Select backfill <br />4 (min) 6 (min) <br />RECOMMENDED PRACTICES <br />• Have island forms, boxes, and shear valves in place before dry fitting. <br />• Lay out and dry fit primary and containment piping at the same time. <br />• Allow sufficient clearance when dry fitting the primary to accommodate the <br />-- containment fittings. <br />Dimensions of containment <br />fittings may be found at the end <br />of this document. <br />3 <br />