Testing the Relief Valve

Part of my duties, while I worked offshore, was to assist in testing the safety equipment on the platforms. We tested the high and low pilots on the wells, the fire loops and the relief valves on the separators.

The separators were pressure vessels about 5 feet in diameter and 15 feet tall. The gas came through an inlet at the bottom and was forced up through numerous trays inside the separators. As the gas passed through the small holes in the trays, the moisture would condensate on the bottoms of the trays and drip to the bottom of the separator. The drier gas went out the top and the moisture was collected at the bottom as condensate; a clear flammable liquid. The separators had floats attached to valves. When the liquid reached a certain level, the higher pressure of the gas would force the liquid into the liquid pipe, after the floats opened a valve.

At the top of each separator were two flanges. One flange was for a rupture disk, which was a piece of metal designed to rupture at a pressure below that of the vessel. It was the fail-safe, when all else failed. The other flange mounted a relief valve to the separator. This was calibrated to relieve pressure. My job was to hook up a hose from the high pressure of the well to the valve, and turn a nut to calibrate the valve.

Access to the top of the separator was by a ladder. There was a tiny platform on which I would stand to hook up the hose and perform my task. After placing ear muffs to prevent hearing damage - due to the noise when 1200 psi gas was released to atmosphere - the safety man on the platform would pressure up the hose until the valve released. If the pressure at relief was wrong, I calibrated the valve until it was right.

One winter day, while working on the platforms, the temperature reached the point it was too hot to wear a coat zipped up, but too cold to go without. We were calibrating a relief valve, so I climbed up the separator, hooked up the hose and waited, while the safety man pressured up the hose.

I was soon rewarded with the deafening blast of gas and a new sensation: floating horizontally, while I held on to the top of the ladder. It was like one of those cartoons, when Wiley Coyote held on for dear life. Within seconds it was over and I found myself standing on the tiny platform; shaking like a coon dog passing a peach seed.

My coat, which was unzipped, caught the full brunt of 1200 psi gas shooting out of a 4 inch pipe. I'm sure a physicist could figure out exactly what force was exerted and I can attest it's substantial. If my reflexes hadn't kicked in, I would have been launched in an arc that would have ended 30 feet down into the Gulf of Mexico - if I missed everything on the way down.

From that point on, I was obsessive when we checked relief valves. Nothing was loose and I was damn sure to stand as far to the side as possible. I was lucky one time. Nothing guaranteed I'd be lucky again.