02.07 What equipment is needed to outfit underground tanks?

Most underground tank installations require the specification and installation of these devices:

1. Tank hold down straps. The straps are specified and provided by the tank manufacturer to resist bouyancy loads from groundwater.
2. Tank sumps and penetration seals for pipe and conduit. Tank sumps are typically fiberglass or steel. They are typically single wall except in California where they are double wall. The sumps are bonded to a collar on the tank shell that surrounds the tank openings or it is bolted to a tank manhole cover. Rubber assemblies of various designs are used to seal pipe and conduit penetrations into the sump.
3. Manway frames and covers protect the sump risers and other tank equipment risers. They are typically designed to resist vehicle loads and to transfer these loads to the surface concrete slab or manway collar. The manway frames and covers are isolated from the sump risers which are not themselves load bearing, and they also allow for minor settlement of the slab at grade without causing a load on the tank sump. Specialized manyway frames and covers incorporate fill pipe access and spill containers. Manway covers are commonly steel, however composite lightweight or hinged and lift-assist covers are increasingly used for ergonomic considerations.
4. Fill Point Adapters / caps, spill containers, and overfill prevention valves. Fill adapters allow for the connection and sealing of fuel delivery hoses. The fill connection point is located within a 5-15 gallon spill container which is typically a bellowed plastic construction with a water tight load bearing cover. The overfill prevention valve is a mechanical float type valve in the fill pipe within the tank. The float closes the fill pipe at a maximum 90% tank fluid level.
5. Leak sensors for tank interstice, tank sumps, and piping sumps, tank level transmitters, and sometimes electronic line leak detectors are installed at the tank and wired to the tank monitor control panel.
6. Submersible fuel pumps where used are installed through a 4 inch tank opening with a short riser pipe.
7. Suction systems typically use foot valves to maintain pump suction prime, and extractor fittings at the top of the tank for footvalve servicing.
8. Vent caps are.