Earlier this week we got called out concerning a fire/explosion in a Chemetron Series 3000 Oxygen Manifold.
The overview of the incident is as follows:
The manifold went into alarm for "Secondary Bank In Use" when the right bank became empty. The master alarm was silenced, and the employee went into the manifold room. The employee put on gloves, silenced the local audible alarm inside the box and then closed the box. The right bank had two cylinders hooked up one was in use, which was now depleted, and the other full cylinder was in the off position. The employee then shut the empty cylinder, and opened the full cylinder with the right hand. The left hand then immediately went up to protect the face from the rapidly expanding fire/explosion. The employee left the room and went for help. Fortunately, for all involved, only minor injuries were reported. There is a sprinkler head directly above the manifold, and it did not go off. There were smoke detectors in the room. I saw them being replaced later that morning, but do not know if they annunciated upon the room filling with smoke. The fire seemed to self extinguish once the consumables were spent. It is believed that this all occurred almost instantaneously.
The current theory is the ignition source was the typically very hot solenoid. It was noted by personnel that there was a leak inside the (oxygen) manifold. The fuel would be the plastic parts. The pigtail and header looked brand new inside so it does not seem like the ignition source was from the cylinder.
Any thoughts/input?