Accidents in the process industry are mostly related to procedures that do not occur frequently and at the same time can have catastrophic results when performed incorrectly. 75% of the accidents in the process industry happen during startups, shutdowns and maintenance. In 50% of these accidents, one root cause is incorrect operation of manual isolation valves. Valve interlocks are mostly used on Pressure Relief Valves (PSV), but there are many applications where valve interlocks are an added value by protecting people, the environment or company assets.
Pigging operations are generally recognized as highly dangerous and even deadly. Operators can come in contact with dangerous gases, often under high pressure. Valve interlocks avoid human error and subsequently, dangerous incidents.
Inert Gas systems are often used on vessels like a FPSO to create safe storage at sea. Typically, at least one of the valves connecting the vessel to the inert gas system needs to be open at all times. By implementing mechanical valve interlocks on the block valves one line is always guaranteed to be open at all times.