Abstract: A vessel for containing an electro-conductive fluid, the vessel having a laminated wall structure and including an outer structural shell, an inner corrosion-resistant lining made of electrically non-conductive material, constituting a barrier between the structural shell and electro-conductive fluid in the vessel. An electrically resistive medium is mounted between the structural shell and the corrosion-resistant lining, the resistive medium carrying an array of electrodes mounted in spaced apart relationship at fixed and known locations. A main electrode is mounted in the vessel extending into the electro-conductive fluid which forms an electric path between the main electrode and the resistive medium in occurence of a fault in the corrosion-resistant liner, such that electro-conductive fluid is allowed to contact the resistive medium. An electronic controller impresses a voltage difference across electrodes of the array for causing electric current to circulate through the resistive medium.

Abstract: A laminated vessel or pipe having an outer wall of fibreglass reinforced polyester, an inner wall of corrosion resistant thermoplastic and an electrical conductive layer between the inner and outer walls. A probe of inert material is inserted into the tank or pipe and is connected to a source of electrical power and with an alarm system and the electrical circuit is completed with a connection to the electrical conductive layer in the vessel or pipe.