Our Industry has implemented the use of safety relief devices to protect equipment and the public since its earlier days. At that time no valves were permitted to be installed upstream of a safety relief. Field personal quickly realized that it was impossible to repair, test or replace these devices without completely venting upstream volumes to perform their task.

There was one safety relief device that was completely overlooked from this practice, the “Storage Tank Thief Hatch”. This occurred for two reasons: The testing was not required for a relief under 5 psig and it was attached directly to the tank with a bolt pattern that does not conform to any valve.

Until now, the Effect inc. patent pending “Hatch Valve” is the long-awaited lock open block valve for a Thief Hatch. This valve will do for the Industry today what the block valve has been accomplishing for high pressure reliefs for 20 years. Thief Hatch repairs and testing can now be performed safely and without venting (emissions).