Earlier this year I wrote about the EPA Safety Alert regarding having high expectations of an Excess Flow Valve being a reliable safeguard to stop an uncontrolled flow of a HHC/EHS. This article is another example of how these valves should NOT be considered a safeguard and most certainly should NOT be the sole layer of protection for excess flow from a leaking hose/pipe. About 3:45 a.m. on July 14, 2001, at a chemical plant in Riverview, Michigan, a pipe attached to a fitting on the unloading line of a railroad tank car fractured and separated, causing the release of methyl mercaptan, a poisonous and flammable gas. About 4:09 a.m., shortly after the Fire Department chief arrived on the scene, the methyl mercaptan ignited, engulfing the tank car in flames and sending a fireball about 200 feet into the air. Here is the incident break down…
Do NOT rely on Excess Flow Valves (EFV)
