My workshop blew up

Report in New Zealand news:-

Six students were injured when a blast ripped through an engineering classroom about 1pm yesterday.

Four of the students were rushed to hospital in a critical condition although all but one had improved by today and had been taken off the critical list.

The blast is thought to have been caused by acetylene leaking from gas bottles stored in a room behind the classroom. _______________________________________________________________________ I set this metal shop up years ago and taught metalshop in it for several years. I was terribly distressed today to hear of this accident. It has made headline news on our national TV and the sight of my beloved workshop with tin snips driven into the wall, all the windows blown out by the blast and pools of blood on the floor had me near to tears.

Question If acetylene was leaking into the room would you not smell it and be warned? Would it stay at floor level and not be detected? It appears the blast was ignited by sparks fron an angle grinder.

I must replace my old rubber acetylene hoses which are cracking.

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You're not supposed to store acetylene inside a building. They were violating standard safety procedures. Bottles should be stored outside under a shed roof to keep the sun off. Acetylene has the widest explosive range of any fuel gas when mixed with air/oxygen. Bugs

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An combo alarm for CO and explosive gas sells for less than $50. I'm surprised that building codes don't require them in every building where LPG, NG, or other flammable gasses are used. Last month a resort lodge in Panoia Colorado was completely leveled, with 11 dead from a propane leak in the basement. One of the guests complained about smelling gas, but a teenager at the front desk told him not to worry, it was just a little sewer gas...

And yes, they were idiots to store the acetylene tanks > Report in New Zealand news:-

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Tim Killian

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David Billington

One of the volunteer volunteer firefighter's found his stepson was one of the 7 injured by the explosion.

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I don't know about acetylene, but sometimes we miss smells when they come on gradually. Once, many years ago, my friend and his wife came to spend a few days in my home. At one point, I left them to go do some food shopping. When I returned, I was horrified to find the house smelling strongly of gas, with them sitting calmly in my living room. (they were both smokers, but thankfully, had not chosen that moment to light up) When we sorted things out, I discovered that they had decided to pop our supper into the oven. They were not familar with old gas ovens and had no idea what that pack of kitchen matches was for. I was very lucky to find my friends still there and my house still intact!


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Vaughn Simon

Could be the diaphragm in the regulator. We had one leak and burned a guy, when he lit his torch again after returning from lunch. Company policy now is to turn off all tanks and bleed the pressure off all regulators when not in use.

Richard W.

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Richard W.

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carl mciver

EveryONE should do a static bleed down check on their OA system when they first turn it on. It could save you some singed gonads. Bugs

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How does one do that? My dad gave me a small, older OA rig last year. I think I've used it once.

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Rex B

I don't know what the other poster had in mind, but the way I checked out my O/A rig when I first got it was as follows:

I cleaned off the cylinder valve threads and seats first

Mounted the regulators

Connected the hoses

Made sure the pressure adjustment handles on the regulators were unscrewed

The torch handle valves were closed

I then cracked the acetylene tank main valve until the pressure showed on the high-side gauge and turned it off again. When I initially did this, it bled off fast to zero, I had a leak. Soapy water confirmed this. I looked at the connector seat on the regulator's tank fitting, it had a small nick or gouge. A trip to the welding supply got a replacement CGA fitting. Repeating the test, the high-side gauge stayed up for about a half-hour. I did this with the oxygen tank, too, no problems there. The fitting was like a $5 part and it took about 10 minutes to replace.

To check hoses and handle, I cracked the tank valves again, screwed the regulator pressure adjustments in until I had about 10 lbs on the low-side gauges, then closed the tank valves. The old hoses were badly weathered, so I had replaced them without checking them first, cheap insurance. The pressure with the new hoses stayed up for as long as I was willing to wait, so the connections and handle valves were good, as was the regulator. If pressure had bled down, it would have been soapy water time again.

It's really easy to pick up nicks on the seating parts of the regulator and hose fittings, particularly if the outfit has been used by a contractor's workforce. Some of the stuff I've seen come into the welding supply for repair looked like it was used for playing football, after dunking it in tar.

They used to sell screw-on caps for the tank-side fittings on the regulators, I've seen them in old books, wish I could find a source. I've got some old plastic pipe caps/plugs I use on mine, plus I keep the regulators in plastic boxes to keep the dust off. I had some plastic file card boxes that were just big enough to hold one regulator. I don't store the tanks with the regulators mounted and I stick the valve caps back on, too.

If you use quick-connects on your O/A hoses, these need the soapy water check every so often, too. The O-rings can get worn and the fitting will leak.


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