Integrity monitoring system for storage tank insulation

In combination with a container for the storage of fluid material at cryogenic temperature, siad container comprising a structural shell having a thermally insulating lining incorporating at least one fluid-impermeable barrier, a detection system for detecting integrity impairment of such barrier in which system there is provided, in each of a plurality of notional zones within the projected area of the said barrier, at least one detector in the form of an electrical conductor which is distributed over said zone and is connected to a source of electric current and to a warning device located outside said container and actuatable in dependence on the electrical current conducting function of such conductor, such conductor being disposed in a physical relationship to said barrier such that said conductor is affected by impairment of the integrity of the barrier causing fluid leakage depthwise of said lining within the zone to which that conductor pertains, whereby the said current-conducting function of such conductor undergoes a change causing actuation of the appertaining warning device.

A container for the storage of fluid material at cryogenic temperature, wherein said container has a structural steel shell having a thermally insulating lining comprising a cellular matrix of elastomeric material providing a primary fluid-impermeable barrier exposed to the container contents and a secondary fluid-impermeable barrier spaced between said primary barrier and said steel shell, said lining also comprising volumes of thermally insulating load-bearing material enclosed in the cells of said matrix;

• and wherein a detection system for detecting impairment of the integrity of at least one said fluid-impervious barrier is provided, such detection system comprising, in each of a plurality of notional zones within the projected area of the said lining, at least one detector in the form of an electrically conductive foil which is distributed over said zone and is connected to a source of electric current and to a warning device outside said container, said foil having a temperature-dependent coefficient of electrical resistance to cause operation of the appertaining warning device in the event of cooling of such foil caused by leakage of cryogenic fluid depthwise of said lining within the zone to which that foil pertains;
• the detectors belonging to different said notional zones being connected to different said warning devices.