Oxy-Acetylene In Garage/Residential Environment

[hotrodder]

Personally i've never understood the paranoia with acetylene, pure oxygen on the other hand... not stenched like fuel gases so a leak isn't immediately obvious but an O2 enriched environment ain't exactly safe
FWIW while max flame temp with propane is a bit lower (stil waaaaay higher than melting point of steel) oxy propane produces more BTUs of heat than oxy acetylene, less in the primary flame but waaaaaay more in the secondary/outer flame. That's part of the reason why oxy propane is no good for welding, the main one is it's stoichiometric O2-fuel ratio. Acetylene is unique(?) in that combustion in the secondary flame uses O2 from the surrounding air creating a kinda shielding effect that prevents oxidised welds
ETA obviously none of that is useful when trying to convince insurance companies or landlords that you need acetylene

 

[Brad93]

Pure oxygen is pretty dangerous, flash fire/explosions frm the smallest amount of fuel.

 

[brightspark]

the only time ive ever crapped myself with gas was i lost a full 10lb bottle of propane the torch was on the floor turned off but the regulator wasnt . i must have stood on the torch and knocked it on and lost the lot then i found out where it went al -in my pit--7 foot deep and 10 foot long. ohh s...hit . opened all the doors and blew it all -out with a large fan another learnt lesson

 

[doubleboost]

Slightly off subject
A bloke in the ship yard cooled himself down with the oxy from a cutting torch
He lit a cigarete on the bus going home
His clothes were saturated with O2 he could not be put out and died

 

[Screwdriver]

Er no. If it's flammable you need the triangle to make a bang, therefore shed full of flammable gas = no bang.

Plus it will all be at ambient pressure as its been released to atm so not under pressure

Oh yes. A shed full of oxygen + acetylene is a gigantic bomb waiting to go off. The fact that it is not "under pressure" is factually incorrect (it's at 1 atm) and if you mean the high pressure in a cylinder then that's also wrong because it is far more explosive at lower pressure.

A full canister of propane is less of a hazard than an "empty" one for precisely the same reason. I'd love to see this tested on myth busters but if you nicked a full can with a grinder, you'd get a sheet of flame as the liquidised high pressure gas escapes and sets on fire. Do the same with an empty cylinder and the residual gas will explode in a single cataclysmic high speed burn.

S.

 

[voipio]

Hmmm, O2 saturated clothes sound like a myth, unless he went home in a gas tight suit.

 

[doubleboost]

Hmmm, O2 saturated clothes sound like a myth, unless he went home in a gas tight suit.

It could well be a myth but I have herd it from 2 different people
surprised no one has mentioned the "accetyline glove"

 

[hotrodder]

Dunno whether stories about people burning to death after (stupidly) cooling/blowing themselves down with O2 or hanging jackets on a cylinder that was leaking etc and then lighting a cig but > 24% O2 is considered enriched and stuff noticably burns more easily/faster/hotter with just a little more O2 present. Vids of that are boring and couldn't find a shed full of O2 + a fuel gas so here's a cardboard box with methane + air versus methane + O2...

 

[brightspark]

another one was a bloke -nipping half his fag out and putting it behind his ear and it was smoldering. there was an -oxy bottle leaking in room and-the fag flared up burning his ear hmm i wonder

 

[HMB]

Well I for one wouldn't like to be the one switching a light on in a shed full of acetylene,
View attachment 76484 View attachment 76485

Nice photos but looks like you don't quite get the fire triangle bit

Fuel - o2- heat

If there's lots and lots of fuel and 'a' spark it's extremely doubtful it's going pop. Reason being? The room would be saturated with the flammable gas and no o2 to help it. Sorry to bust your myth


Worked in petroleum industry for many years

 

[Woody.v8]

Nice photos but looks like you don't quite get the fire triangle bit

Fuel - o2- heat

If there's lots and lots of fuel and 'a' spark it's extremely doubtful it's going pop. Reason being? The room would be saturated with the flammable gas and no o2 to help it. Sorry to bust your myth


Worked in petroleum industry for many years

I get it just fine, Fuel= gas, o2= well ventilated shed, Heat = spark from light switch/fag etc.
I'm not saying it would but ive made enough acetylene bombs to let you turn on the light if your willing.
I suppose all the domestic gas leak explosions are just myths too....

 

[HughF]

but if you nicked a full can with a grinder, you'd get a sheet of flame as the liquidised high pressure gas escapes and sets on fire. Do the same with an empty cylinder and the residual gas will explode in a single cataclysmic high speed burn.

You'd get a blevee as the reduction in pressure causes the volume of liquid to instantly turn into a gas, which occupies a huge volume. The sudden increase in volume will rip the cylinder clean in two.

 

[Woody.v8]

You'd get a blevee as the reduction in pressure causes the volume of liquid to instantly turn into a gas, which occupies a huge volume. The sudden increase in volume will rip the cylinder clean in two.

Or in the case of acetylene self ignite due to excessive flow.

 

[HughF]

Yes... I was referring to lpg specifically

 

[Screwdriver]

You'd get a blevee as the reduction in pressure causes the volume of liquid to instantly turn into a gas, which occupies a huge volume. The sudden increase in volume will rip the cylinder clean in two.

Never heard of a blevee but no liquid will "instantly" turn to gas, solids can sublime but a pressurised gas will make a run for the door, that's all. Unless it is highly unstable it wont necessarily self combust or explode either.

Of course it will allow the liquid to rapidly expand but nowhere near as rapid an expansion as an explosion. The key issue is that at lower pressure, a flame front can travel much more quickly causing the entire contents of a bottle to expand explosively.

 

[HughF]

Boiling liquid expanding vapour explosion

 

[Screwdriver]

Boiling liquid expanding vapour explosion

This is more relevant to your argument.

 

[doubleboost]

If you get the air fuel ratio right most things will go bang
flower , saw dust , coal dust , petrol
Oxy Acetyline at the "sweet" mix is truly devastating

 

[Pete.]

An oxygen-enriched atmosphere causes things that wouldn't normally burn to readily combust but you still need a heat source and fuel.

Acetylene inside is a lot more dangerous than acetylene outside. Unless it's a totally flat-calm day then outside it will be carried away by the wind but inside it'll hang around and as stated above if it ignites in a confined space it can literally blow things apart.

The one thing that makes Acetylene so much more of a hazard than other fuel gases used in welding is it has the widest flammable range of any gas. It will explode between 2.5 and 100% concentration so almost any kind of leakage in a contained area is a potential bomb.

 

[Rrunnach]

I've witnessed pipe strangler/welder hump O&A set around various sites in the past, they're not that fragile, however, proper setting up, leak testing, purging up, purging down, will keep the operater safe. Be compliant with BCGA rules and regs, flash backs in date, etc. All should be well.