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| Proforma Safety, LLC Proforma PSI…when performance counts. Valve Blowout Due to Hydrates An employee was injured recently when a ½ inch valve blew out due to trapped pressure, reinforcing the need to thoroughly examine operations being preformed when a system has pressure on it. Two employees were changing out a 1/2" needle valve for a 1/2" ball valve on the production well 'B' annulus management system pipe work. The system had been isolated and the valve opened to check for residual pressure, with an insignificant amount of pressure released and stopped almost immediately. The men believed the system to be safe and began work to remove the valve. After 1 1/4 turns, there was a release of trapped pressure which caused the valve to be ejected from the pipe and thrown across the deck, catching one employee on the side of his neck and face, causing numerous small lacerations and redness. It is believed that formation of hydrates within the system caused the buildup of pressure. The primary learning from this accident was that potential risks from hydrates or trapped pressure had not been identified, and the original annulus management design did not identify problem with use of needles valve in 'dirty service'. To confirm system pressure, one would have to rely on opening of a single needle valve. In addition, the position of the injured individual caused him to be struck by released pressure. To avoid such an incident, personnel should be made aware
of risks due to hydrate formation and should review the way
in which system pressure is checked prior to commencement
of tasks involving breaking containment. In addition, personnel
should not use needle valves to depressurize in systems where
it’s possible that hydrates have built up. The experience,
competency and training of all personnel involved with work
on pressure systems should be evaluated, and appropriate caution
taken when positioning personnel to work on pressure systems.
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