Safety on deck.
Explosion protection for LNG transportation and storage around the world
Highly recognisable, even from a distance, LNG transport vessels are often equipped with spherical tanks measuring at least 40 m in diameter. They typically have a load volume of 125,000 to 150,000 m³ – the largest can even hold 266,000 m³. In modern designs, huge storage facilities within the ship's hull are used, featuring a thin membrane layer made of Invar steel that is surrounded by an insulating layer.
In these situations, the highly flammable LNG demands strict safety requirements. For LNG transport, type "2G" tankers (IGC code) are used and comprehensive explosion protection is a crucial part of their design. Among other things, the IGC regulates the design of electrical equipment, fire protection equipment and extinguishing equipment, as well as ventilation systems and gas detection systems.
Onboard tankers, in accordance with the standard IEC 60092-502, a zone classification (Zone 0 to Zone 2) similar to that used on land according to IECEx and ATEX is used. The zone inside the tanks and conduits is, of course, Zone 0. Pump rooms and the area around outlet valves, for instance, are classified as Zone 1. Spaces that are 1.5 to 3 m away from Zone 1 are classified as Zone 2. Products with the types of protection typically used on land can be used in these zones. R. STAHL's extremely comprehensive explosion protection portfolio provides safe solutions that have been optimised in terms of their cost and function, correspond to marine standards, and are suitable for every application onboard an LNG tanker. These include, for instance, remote I/O stations, HMIs, isolators, light fittings and alarm systems, which all have been granted the required certifications. Pumps that are installed in filling retention systems are equipped with many elements, including load disconnect switches with AC3 switching capacity. Safety switches are used to disconnect safely from the power supply when necessary, such as during the degassing process.