Abstract: Systems for fluids (including liquids) and materials with a fluid phase. The material is confined in a primary containment, and a secondary containment is used to keep fluid leaking from the primary containment from the surrounding environs and to keep leachates and other fluids from the primary containment. A safe, non-toxic liquid in the interspace between the two containments is employed in detecting leaks in the containments and can also be employed to protect the containments against chemical attack.

Abstract: Methods of and apparatus for detecting the leakage of fluids from containment vessels. The tank is surrounded by or lined with a generally fluidtight envelope, and a vacuum is applied to hold the envelope against the tank and thereby control and limit to a very small volume the space between the primary containment, be it the vessel or liner, and the envelope. Fluids escaping from the containment vessel collect in that space. Collected fluids are evacuated; and fluid withdrawal information is processed, providing an advisory if a leak occurs or continues and/or information on the magnitude of the leak. An indication of a possible leak can also be obtained by monitoring the pressure in the space between the containment vessel and the encapsulating envelope. A trend-bucking change in that pressure is also an indication of a possible leak. Other installations make use of a second system to detect and evaluate leaks into the installation from the surrounding environs.