Underground LPG Tank Fittings
Although the tank fittings, valves and connections are the same among propane tanks, their placement on the tank is different. Above ground propane tanks will generally have the relief valve and liquid withdrawal valve placed outside of the dome usually on opposite ends of the tank. On an underground tank, all fittings and connections are centrally positioned to be protected by the dome walls and cover. For obvious reasons, it’s not legal to bury a propane tank designed and designated as an above ground propane tank.
Protection from the Elements
Because underground propane tanks are exposed to a completely different set of conditions and elements, certain precautionary and protective measures must be in place to prolong the service life of an underground propane tank.
Tank Coating and Backfill
The outer surface of an underground propane tank is in constant contact with an environment that can be extremely damaging. For this reason the outer surface of the container must have a protective coating and be covered with a material that will not be harmful to the shell of the underground propane tank. Although propane tanks designed for underground use are coated with a protective material at their point of manufacture, the container can be compromised during installation if the backfill is made up of rocks and/or abrasive materials. Underground tanks are designed to exist in harsh environments but if the backfill is made up of a material such as gravel (which can cut through the tanks protective coating), the anode bag may not adequately protect the tank from underground currents. For this reason, sand or firm earth free of rocks and abrasives should be used to cover an underground tank after installation.
Underground Tank Location
Underground propane tanks should be in a place where they are not going to be underneath any sort of vehicular traffic. For instance, a propane tank placed under where a driveway is to be installed is not a good idea and nor is it legal. The underground tank should be placed in a location where it is not going to be underneath anything other than dirt and earth.