Abstract: An underground storage tank installation. The excavation is to a predetermined depth to permit placement of a storage tank of desired size therein below ground level. At least a pair of opposing side walls of the excavation are sloped to minimize the danger of collapse. The excavation is provided with a base layer of footing material by appropriate backfill and a double shell storage tank is rested on the base layer in the excavation. Double shell piping conduits and a leak detector is installed between the shell and ground level. Backfill material is placed into the excavation to cover the tank and piping and leak detector structure to a height adjacent ground level. A solid slab is positioned over the tank and the backfill layers with appropriate apertures to permit access to the underground piping conduits and the leak detector. The excavation, backfilling, placement of the tank, piping and detector and pouring of the slab are accomplished without the necessity of personnel entering the excavation.

Abstract: A system to detect leaks, monitor levels, activate alarms, etc. in which a specific material in the system dissolves or disintegrates on contact with a liquid, gas or vapor which is to be monitored.