Oxyfuel flashback arrestors?

I had a close call with an acetylene torch. Back in the late 90's I was part of a team, renovating a floor of the Knickerbocker Club in NYC. in one of the rooms there was a heavy piece of steel angle protruding a few inches from the concrete floor, in a place that was formerly a wall but now was to be open space. It was about 6"x4" and a ½" thick, someone proposed grinding it off but that would have taken a while and we only had one cutoff disc. Earlier, I had noticed a Oxy-Acetylene rig in the clubs shop, so I offered to torch it off. The club's head of maintenance brought up the torch rig which appeared older but hardly, if ever used. It was already set up for cutting so I just checked the connections and started cutting the steel. I got most of it off and was going back to knock off a bit that was still sticking out. Suddenly there was a loud whistling sound and flames were shooting out from the base of the torch, one of the most heart-stopping moments in my life! I immediately shut the tank valve and it stoped. Upon examination it there were plastic seal washers where the hoses connected to the torch, the one on the acetylene side was split. I had never seen these before, I doubt they belonged there. Maintenance guy said the torch had been there when he was hired about 15 years prior and that he had never seen anyone use it. I don't know if it was a flashback or the leaking gas simply ignited from the torch. Either way, it was a very learned lesson.
 
Away back in the old days, I had a crew hanging a new conduit run over the annealing ovens. The ovens were cool, the conduit was for an upgrade to the oven controls. A spark(?) burned through the acetyline hose at the regulator and it caught fire. The regulator burned down to the tank, increasing the flame. I notified the crew up on the staging. They ran. As did I. We notified the appropriate people and then hung around the mouth of the oven, watching. The salesman from the welding supply house calmly walked up to the torch buggy and valved off the oxygen tank. He then wheeled the buggy out to the "pipe run" to an open area and let it burn out. We were told there was no explosion hazard and with the oxygen off in an open area, no real fire hazard.

Shortly thereafter I acquired my own torch rig for home use. As soon as the arresters came available, I acquired a set and mounted them on the torch. Just another sea story from the old (pre OSHA) mill.

.
 
Something interesting I learned in the fire service on dealing with propane tanks was not to put out a fire coming out of a leaking tank if it couldn't be turned off. This is counter intuitive to what one would think. The thought behind this is that the gas being heavier than air if leaking and not being burnt off will settle in low areas and create an explosive condition. One thing I still remember to this day when the Roseville train yards blew up was the mushroom cloud from the propane tank cars that bleved. They looked just like the classic nuclear explosion mushroom we see in pictures.
 
Is there PM one can perform that will minimize the risk of these types of events?

I bought my setup only a few years ago, but I would hate to experience anything like this because I failed to inspect my gear.
 
The most important thing to check for are leaks. Never use any oil or oil based sealants on the oxygen . Common sense goes a long ways in preventing any problems. Check the surrounding for anything flamable.
 
Get a little folding tip cleaner and keep the tip clean. Little hot specks can cause flashbacks or even worse plug the orifice. If the tip gets wallowed out from too much enthusiastic cleaning, replace it. Don't get the tip too close to the work, since something might blow back into it. When working in a confined crevice which is hot, avoid getting the tip too hot to discourage burnback. Keep the flow rate at the minimum suggested in the manual, else there isn't enough gas flow to cool the tip, and again troubles can occur. The rule about avoiding oil-based fluids is very strict on the high pressure side of the regulator and less strict on the low pressure side. Still, don't allow grease to accumulate on the hoses, and oxygen-safe soap or sealant is safer (get these at the welding store).
 
Looks like I'll be investing in the Victor Journeyman Edge 2.0 kit. Cyberweld.com has it for basically Victor's wholesale price ($535) which is barely more than what some places charge for the original Journeyman 450 kit - but the new one comes with a hose, extra welding tips, and a few more things -- including a tip cleaner
 
Back
Top