Thread: Fire Extinguisher Fun

http://www.ehs.pitt.edu/assets/docs/...ble-metals.pdf

Originally Posted by cba_melbourne

http://www.ehs.pitt.edu/assets/docs/...ble-metals.pdf

Glass beads are another method of extinguishment of metals even though it's not mentioned in this documentation. Simon

Originally Posted by janvanruth

Years ago i was working on the spots of rust on my car with fine steel wool.
I had to weld a spot using a stick welder.
A spatter from the welding fell into the steel wool.
I burnt brightly and fast!
No oil or any chemical in the patch just fine steel wool.

It's amazing what will burn if there is enough surface area available to burn. Cheers, Simon

Originally Posted by BobL

I realise you are talking about a house fire but it's worth noting what happens in a metal fire, where 50L of water can become 85,000L of oxygen and hydrogen gas.

Dead right, a similar effect occurs in the case of seriously large fires such as chemical refineries where the heat produced can actually cause water to break down into oxygen and hydrogen.
Water definitely will not put out a metal fire.
I don't know if anyone has noticed, but the old structure fire tactics called for 63mm hose lines and an uncontrolled (operator can't turn it off) jet or stream type branch at ~700kPa (100 PSI), which delivered a lot of water and made equally as much mess. Modern fire fighting typically uses 25mm lines at ~2,500kPa (350PSI) delivered by a pressure compensated, controlled branch which is set to a fan spray. The greater pressure combined with the fan pattern atomises the water more finely making the transition to steam more efficient, thus leading to far less water usage, assisted by the operator being able to shut the water off when not required. Trials are underway using as much as 10,000kPa (1430PSI) combined with between 0.1 and 1.0% A class foam for bushfire fighting in the blacking out phase.
A class foam has been trialed for structure fire fighting, but the negatives seem to outweigh the positives at this point in time.
As a matter of interest, there was even a branch available for fighting fires in LIVE electrical equipment. Allegedly it produced pulses of water that did not allow electricity to conduct back up the stream. The one user purchaser that I am aware of still has half a dozen in the store in pristine condition - nobody trusted them enough to use them. I certainly wouldn't.

Originally Posted by Karl Robbers

Dead right, a similar effect occurs in the case of seriously large fires such as chemical refineries where the heat produced can actually cause water to break down into oxygen and hydrogen.

This also happens when water hits the core of a hot nuclear reactor and is what cause the main explosion at Fukushima. This is also considered a "viable" and safe way to produce large amounts of hydrogen as might be used in hydrogen vehicles. The beauty of using Hydrogen is of course that when burnt it makes water.

As a matter of interest, there was even a branch available for fighting fires in LIVE electrical equipment. Allegedly it produced pulses of water that did not allow electricity to conduct back up the stream. The one user purchaser that I am aware of still has half a dozen in the store in pristine condition - nobody trusted them enough to use them. I certainly wouldn't.

We have some very expensive misting water extinguishers at work for use on live electrical/electronics. They are in stainless steel vessels similar to the Vaporising Liquid MRI extinguishers. They were just being put into circulation as I was retiring.

If anybody wants to know how much mess a dry powder extinguiser makes...I can tell you first hand......heaps.

back when I was about 19, I fitted a set of extractors to my cortina....they had a plastic clutch line...which contacted the extractors and up she went...brake fluid burns well.

Some months earler I have been give a couple of old style chubb 1Kg fire extinguishers...the ones with the CO2 cartridge in them.

ANY way I punched the button on top and it put the fire out in very short order.....but these old things once they started they did not stop till all the CO2 was gone.

Well I had white powder all over the car and all over the back yard......there was white stuff from ....hole to breakfast time.

but it is the fact that the stuff gets everywhere that makes them work so well.....every little grain of this stuff carries its fire fightin goodness.



On another matter.

One thing that seeems to be neglected these days is the fire bucket......

just a tin bucket full of sand.....around the workshop....a bucket of sand just cant be beat for those small ocupational fires that may occur when welding and the like.

and a bucket of sand will keep down all sorts of fires including burning matals and phoshporous (not that many of us would have phosphorous in the workshp)

I keep a metal bucket with my own brew.....50% fine dry sand and 50% diatomite...arround the workshop.

its great for dealing with spills too...or for that matter nearly anything that is or becomes hazardous.



cheers