Fire safety

[Brum1]

Yesterday morning, I lit the gas under the kettle and got back into bed to await the whistle.

What would I do, I asked myself, should a fire break out?

Easy, I thought, wake up the kids and Mrs Brum, then evacuate the caravan before turning off the gas at the cylinder.

Oops...How would I get to the gas cylinder, because the locker key would be somewhere inside the burning caravan.

Made me think for a while.

 

[bigbilly]

Brum - I think that you make a good and valid point !

Reviewing my own situation I expect that for 90% of my caravanning I use a 13Kg bottle which is outside the van anyway. For 5% I use EHU's and recently have just not bothered to take gas with me. The remainder are mostly on CC/CCC rallies/meets when through laziness the front compartment is never locked on the undersatnding there is always somebody about !

I'm not sure how dangerous gas is in the 'open air' but the gas in the bottle is a literal bomb !!

Bill

 

[Colinn]

Hi Brum,

This very important subject had a good airing on the Forum in May. I posted after the shock of seeing a van burn to a blackened shell in minutes! The Topic was in General, headed Salutary Warning - van burned to the ground, started on May 28. You may be interested in having a trawl back.

 

[Rita1]

the posting Colinn was on about

http://www.practicalcaravan.com/newforums/fm_messages.asp?FO=5&FM=333204

 

[rob_jax]

Bill

"I'm not sure how dangerous gas is in the 'open air' but the gas in the bottle is a literal bomb !!"

Nope - it's the other way around - gas in the bottle is safe, gas mixed with air is the problem.

Gas in the bottle - The worst that could happen is the bottle could break - and then that'd be like a tyre bursting - the pressure in a Butane bottle is similar to many tyres (more if the gas is Propane) - it could be dangerous to someone close-by.

Gas mixed with the "open air" is the real nightmare - ounce for ounce, gas mixed with air has more explosive power than TNT or other high explosives.

If the gas from a small 5kg bottle was allowed to leak and mix with the surrounding air for a few minutes, then ignite, that would have the potential explosive power of 7kg of TNT

Robert

 

[GrahamSouthBrum]

Gas in the air at the right proportions is leathel yes, BUT that would be in confined situations unless it was a major leak in the open.

The flammability of petrol is something like top end 85% bottom end 25% petrol vapour /air mix. so any where between 85%/25% petrol vapour to air would be explosive. I am not certain about LPG but I think it is a similar ratio gas to air mix.

A gas leak in the open in small amounts would soon dissperse in a breeze, but as lpg is heavier than air could linger in drains & ditches etc.

When you say explode if you were to get a severe lpg leak that was ignited, the gas cloud would burn as a big fire ball spreading outwards burning every thing in its path, but not explode as such.

For something to explode it must be compressed eg lpg in its cylinder.

If the cylinder is involved in fire the gas inside the cylinder will expand untill the walls of the cylinder stretch to bursting point at which point you will get your explosion.

I have seen several cylinders explode at different times & belive me it is an impresive site, followed by the need to change ones under wear.

G.

 

[rob_jax]

I know a burning gas bottle is impressive, and if the burst disk fails then the resulting fire ball can be very impressive, but that's not an explosion - and even if the bottle ruptured in the fire, and a small explosion occurred - it's still nothing compared to the same amount of gas leaking, mixing with air and then burning.

And the fact that material is compressed and constrained in a bottle has nothing to do with an explosion.

When I design systems for refineries and I don't unduly worry about, say, the high pressure LPG lines, it's leaks and remote ignition sources that everyone worries about.

For instance, the explosion at the BP Texas City refinery in 2005 was caused by a plant outage at an isomerization tower (effectively releasing vapours somewhat similar to Butane), the gases travelled one or two hundred metres until it encountered an ignition source next to a process operators rest hut - and devastated the site.

Compare that to the fire at PetroPlus Coryton (near Canvey Island in Essex) this year which released a similar amount of flammable material, but which burnt at the release point - it vented under very high pressure - but this was just a fire with no extensive damage. No air mix, no explosion.

Robert

 

[GrahamSouthBrum]

Hi Rob,

I suppose it all comes down to what people define as an explosion.

We have to train for backdraft & flashover situations that can be called an explosion.

Have you seen the video on B.L.E.V.Es boiling liquid expanding vapour explosions, where a bullett of gas traveling by rail in the U.S. developed a leak that was ignited. The resulting flame heated the outside of the bullett causing the expanding vapours inside to explode & take off like a rocket.

They found the bullett several miles away.

G.