INSTALL_2008 - Laserfiche WebLink

Home Browse Search

FIGURE 9 Tanks need a minimum cover depth of 36" backfill OR 18" of backfill plus 6" of reinforced concrete (see figure 9). (fit' diameter tanks) ♦ Tanks need a minimum cover of 38" backfill plus 6" of reinforced concrete. A6. FILTER FABRIC Why use filter fabric? ♦ Filter fabric allows the passage of water but helps pre- vent the migration of gravel backfill into native soil. ♦ 'Filter fabric helps maintain the integrity and stability of backfill materials. When to use filter fabric? Containment Solutions requires the use of filter fabric for the following types of installations: ♦ Areas subject to tidal conditions. ♦ Areas subjected to frequently changing ground water levels. ♦ Unstable soils (muck or landfills, see section A4). ♦ Water conditions with silty soil. For other types of installations, the responsibility for de- termining if a filter fabric is appropriate for a specific tank installation remains with the tank owner or technical repre- sentative. FILTER FABRIC INSTALLATION -- DRY HOLE • Line the sides and bottom with filter fabric. • Overlap adjoining fabric panels at least 12 • Place backfill on top of the filter fabric to hold it in place. FILTER FABRIC INSTALLATION —WET HOLE • Backfill ballast is necessary to sink and hold the filter fabric in place in the bottom of the hole. Suitable brand name filter fabrics are listed below. Call the phone numbers listed for local distributors. Manufacturer Product Phone Reemay, Inc. TYPAR 3401 (800) 284-2780 TYPAR 3341 (615) 847-7000 Amoco Fabrics Amoco CEF 4545 (800) 374-6606 & Fibers (404) 984-4444 Hoechst TREVIRAS1120 (800) 845-7597 Celanese Corp. (hole depth less than 10') (803) 579-5269 TREVIRAS1125 (hole depth greater than 10' deep) DO NOT ♦ Use polyethylene as a filter fabric because it will de- grade over time. A7. ANCHORING It is the responsibility of the tank owner or the owner's technical representative: ♦ To determine if mechanical anchoring is required for a specific job site. ♦ To consider all potential sources of water, such as: ❑ Underground water table. ❑ Rain water runoff, flooding, etc. (which may fill a slow draining tank excavation). What is the purpose of anchoring? Mechanical anchoring is used to secure the tank in condi- tions where the tank could become buoyant (e.g. water in the hole). There are two common methods of mechanical anchoring: ♦ Concrete anchor pad. ♦ Deadman anchors. Note: Both methods require the use of Containment Solu- tions fiberglass anchor straps. When do you need to anchor your tank? If water can enter the hole, Containment Solutions recom- mends that tanks be mechanically anchored unless the minimum burial depth from tank top to grade meets or ex- ceeds the values in the following chart. CONTINUED ON PAGE 10 9