Mel E Posted October 8, 2007 Share Posted October 8, 2007 Twive last week, a major motorway and a very busy dual carriageway were closed for an extended period (the latter for almost 24 hours) because vans carrying gas bottles caught fire. The fires were rapidly extinguished, but the Fire Service then waited for the gas bottle to cool down. (Ironically, the acetylene and oxygen bottles near Colchester were in a Fire Service van!) This is happening more and more frequently. How long before action is taken? My idea to solve the problem is as follows: all bottles containing a nominated gas would have to be stored in a compartment that could withstand fire 'attack' for, say 30 minutes. This would inevitably thicken the compartment walls somewhat, but not a lot - a domestic fire proof safe can typically withstand 1000C for 60 minutes without the contents being damaged. I am ignoring the lorry-load of gas - either liquid or cylinders - as special regulations already apply. The question is: would such a compartment add significantly to the cost of a motorhome? It would only be necessary for Propane (bottled at 7 Bar) as Butane is bottled at 2 Bar (twice atmospheric pressure) and so probably not on the list of proscribed gases - even when very hot. Mel E ==== Link to comment Share on other sites More sharing options...
trooper Posted October 8, 2007 Share Posted October 8, 2007 I saw that report,Bleading stupid, once the fire is out and the gas is cooled down a bit, its not going to explode, on a differant subject, years ago I saw a photo in a trade book put out by shell on the safety of fuel oil, of a wooden shed had burnt down completely and the 600 gal diesal tank which was inside still ok, Lets go back to commen sense. cheers Link to comment Share on other sites More sharing options...
davenewellhome Posted October 8, 2007 Share Posted October 8, 2007 I believe this is why the recomendations are for the gas lockers of motorhomes to be lined with sheet steel. Not sure how long this gives as fire protection though. D. Link to comment Share on other sites More sharing options...
colin Posted October 9, 2007 Share Posted October 9, 2007 Acetylene is a whole lot different from a lot of other compressed gasses, it inherently unstable and the cylinders have a 'catylist'? which stops it from exploding when it is in the cylinder under normal conditions, I'm not sure about when they have been 'cooked' in a fire but if there is a 'flash back' in the cylinder they can explode hours later. Link to comment Share on other sites More sharing options...
Fetch Carry Posted October 9, 2007 Share Posted October 9, 2007 Would imagine that the oxygen also in that situation could be dangerous Link to comment Share on other sites More sharing options...
Clive Posted October 9, 2007 Share Posted October 9, 2007 I understand that Acetelene is disolved in acetone which is held in a sponge inside the bottle. A bit like carbonated water but a tad more potent! Oxygen, Propane Butane are just compressed. Some revert back to liquids at relatively low presures and some (like oxygen) do not. Hence the very different bottle pressures for Oxygen and acetelene bottles. How many people turn their gas supply OFF at the bottle when traveling? Or how many don,t? Link to comment Share on other sites More sharing options...
colin Posted October 9, 2007 Share Posted October 9, 2007 A read of this will give you an idea of the problem http://www.london-fire.gov.uk/news/media/BCGA.pdf Question is should road have been closed so long? proboly not, but the cylinder would have to been left there for quite some time being monitored untill it was stable and could be moved. Link to comment Share on other sites More sharing options...
Charlieme Posted October 9, 2007 Share Posted October 9, 2007 A few facts on Acetylene It is very versatile but there are dangers that must be adhered to. In any empty space with a pressure above 9 - 15psi acetylene is explosive if subjected to a knock. Acetylene is therefore absorbed in liquid acetone or dimethylformamide at 25 times its own volume for storage purposes and transportation, Cylinders for transportation contain a porous rock material such as calcium silicate. The cylinders are rated at 250 psi. Acetylene cylinders must be stored outdoors. Leaking gas can be ignited by electrical sparks. Acetylene cylinders must always be stored or transported upright. Bottles that have travelled lying down should stand for 2 hours upright before using to prevent acetone leaking from the torch or other hand equipment. Acetone is a clear liquid and can be detected by a sweet smell. Acetone is also flammable and can leak from a cylinder if laid sideways. Acetylene is lighter than air (just) but will vary depending on air movement. Acetylene is explosive if mixed with oxygen from 2 to 82%. Acetylene should not be allowed to come into contact with copper when it produces copper acetylide an explosive compound. Copper acetylide is an intermediate in several organic chemistry reactions. Apologies for the lengthy details, I believe it’s complete. PS Still working with it at 80 Link to comment Share on other sites More sharing options...
davenewellhome Posted October 9, 2007 Share Posted October 9, 2007 Very interesting Bill and Colin. Bill, I'm a little intrigued about the copper part of your answer as torch nozzles for use with acetylene are usually made of copper. I'm certainly not contradicting you as I definitely don't know the answer but perhaps you can clarify this point for me. D. Link to comment Share on other sites More sharing options...
famcunni Posted October 9, 2007 Share Posted October 9, 2007 Have a look at You Tube under BLEVE (boiling liquid expanding vapour explosion) and you will see why fires involving cylinders are taken seriously. Ok these involve big quantities but even small quantities can produce enough of a blast to kill. If your gas locker does happen to catch fire move everyone as far away as possible (at least 200 to 300 yards away) and wait for the fire brigade. Scary stuff but true. Link to comment Share on other sites More sharing options...
Charlieme Posted October 9, 2007 Share Posted October 9, 2007 Copper acetylide Yes the nozzles or tips are copper but the swan neck leading to the tip is brass as you would know, the regulators also for example, are made of a particular "Brass" mixture, I think its 60/40 % From reading the technical info relating to copper tubing I assume that copper nozzles being heated regularly and very short in length don't come under the same danger hazard There is a lot of technical info on the net, type in 'copper acetylide'. I've extracted one small sentence as follows "Copper acetylide can form inside pipes made of copper or an alloy with high copper content, which may result in violent explosion" This is the reason for the 60/40 brass mixture in components I'm not sure why they refer (in particular) to copper pipes but it certainly is a fact that years ago we always used copper tubing to repair damaged gas hoses. Being a bunch of teenagers who didnt care a lot, we just used whatever was available. We experienced many moments of "fun" as we called it. I dare not describe on here all the 'games' we got up to. We worked at Gatwick Airport, it was wartime. we could imitate very loud machine gun fire to frighten the females (known as dope girls) due to their painting aircraft linen all day with cellulose. I believe the most important safety issue is to understand "The gas", its weight and molecular size etc, this includes Oxygen and others gasses of course. They were wonderful days! Link to comment Share on other sites More sharing options...
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