Thread: Fire Extinguisher Fun

Originally Posted by BobL

but based on the amount of mess and level of (un)cleanliness in sheds I have seen in DIY sheds around the place I'd say most folks don't have that much to worry about it.

when did you visit ...i must have been asleep....

As for setting fire to something...many many years ago I lived with my sister and her partner. She made chips (the fish n chip type) in a pot of cooking oil on a gas stove...well one day she forgot about it and up it went....she did how ever manage to get it out side with minimal smoke damage ...and then rang fire brigade ...that was her 2nd mistake...they attended and just stuck a box over it...well that went up to.....so they got the garden hose...hot flamming oil and water dont really mix...... then they got smart...lol

reminds me of the fire brigade in Auckland...Fire Alarm at Air New Zealand House goes off...brigade attend and up to top of building they go...enter plantroom and first thing you see is two (gas or oil ..cant recall which) hot water boilers. One of which was operating...big clear inspection glass plate on front showed a fire inside. so using the axe they used to chop their way thru the door to the plant room, they chopped off the back plate of the flue and stuck one of the Co2 extinguishers into the fire box extinghuishing the flame ...

ah ah all good, or so they thought.... they noted that the smoke was getting thicker...found the chiller switchboard on fire in the basement half an hour or so later....I arrived just as they were beginning to spray with dry powder types...what a mess it made.

Originally Posted by eskimo

when did you visit ...i must have been asleep....

One doesn't necessarily need to visit - it's very interesting to look at the backgrounds of some photos posted on these forums.

Anyway, following on the same theme, earlier this year I posted a poll on fire safety in sheds.
There were thousands of views (42 members) but only 56 responses.
Bearing in mind the respondents covered both wood and metal workers (most likely more woodworkers) nevertheless the results are quite interesting and if you haven't seen it, its worth a look.
It would be interesting to know the results for the metal work (or substantial metal working) DIY community.
I would hope the results were a bit better.

I have no idea about the validity of these polls.
One thing that concerns me about these polls is that they tend to draw in those that are already "converted" to an issue, maybe because they feel they can tick some response boxes?

Originally Posted by Combustor

Do not despise the Garden Hose, but make sure it is the right one! Not a great expense to get a garden tap installed with a 19mm copper service to it instead of the usual 12mm pipe. Then buy a length of 19mm reinforced garden hose and put a ball cock and nozzle on the end. A short piece of 6mm id tube is OK and will throw a jet 20 metres, so you don't need to get too close. Hang the hose in loose loops over one of those hose hangers, and remember to turn on the tap to pressurise the hose and stop kinks before you throw the whole bunch of hose on the ground and run with the nozzle.
Have been very glad of this setup a few times when welders and grinders have lit up something unexpectedly. Cheap and effective for the home yard or shop where a hose reel is not mandatory.
Made the mistake of enquiring the cost of an installed fire hose reel once. Would need to connect a 25mm water meter, then a 25mm water line to the hose, and the whole lot would need to be surveyed and approved by the local Fire Service. Could have bought a new car for the estimated cost. It was not mandatory for my shop size, so the garden hose solution won, and proved effective when needed.
Combustor.

As we live on a property, we have some precautions in place. Our outside water supply is 32mm poly. The taps are 3/4 inch with 3/4 inch risers. We mostly use 3/4 inch garden hose. We also have an overhead supply tank so if the power goes out there is still a water supply.

When doing things that carry the risk of fire during the fire season I keep a charged 3/4 inch garden hose around close. The pump that supplies the overhead tank is also a pressure pump. I leave this turned on. I use a fire fighting nozzle on the end. This is what should be used. It can be adjusted from a narrow stream that will carry a long distance to a wide misting spray pattern. The latter is best to put out burning grass, wood paper etc. It is largely the cooling effect of the water evaporating that puts the fire out. This substantially cools the area and slows the burning. At the same time it does not blow burning stuff around from excess pressure.

This was learnt from CFA traing and fire extinguisher training at work. When using a water type fire extinguisher we were taught to use a finger over the nozzle to form a spray pattern. A jet covers a small area only and a lot of the water runs away where it does nothing. Having a spray pattern in front of you also reduces the heat reaching you and allows you to approach more closely. A spray maximises the effect.

One doesn't necessarily need to visit - it's very interesting to look at the backgrounds of some photos posted on these forums.

I try to be very careful of the background with my photos. I also crop selectively.

Dean

A couple of comments that I would add to this excellent thread.
I saw more than once the comment that fire blankets can be reused. This is not the advice given by most fire services because there are combustible materials impregnated into the fibers when the blanket is used to extinguish a live fire. These materials may or may not be a problem when/if the blanket is reused at a later stage.
Secondly I would recommend a dry chem extinguisher to anybody that did not need a dedicated CO2 extinguisher for an electrical installation. There is no better all round extinguisher available.
Thirdly, the instructions on dry chem extinguishers are misleading. You know pull pin, aim at base of fire, sweep side to side. The correct procedure is as follows. Check type of extinguisher, check gauge, pull pin, give a short test squirt before approaching fire, approach fire crouched over low, aim at top of flames, squeeze trigger and sweep side to side. Dry chems are at least twice as effective when delivered to the upper section of a fire.
A dry chem extinguisher is the first line of attack for emergency responders everywhere. I have seen a 9KG Dry chem put out a kitchen fire that was well alight and have personally used one to effect a snatch and grab of 3 young children out of the back seat of a burning car. Yes, they make a mess, but a fire will make a lot more of a mess if left unchecked.
All my vehicles and machines have one, the house has one as does the shed. Actually the house has both a dry chem and a fire blanket for an initial attack.
Finally, if in doubt. Get out. Nothing in your house, car or shed is worth dying for.

Hi Simon,
I left the parentheses out as they would have needed explanation, which I didn't have. Thanks for that.
I didn't know about the "missing" class D, not in the RFS pocket book, probably don't expect to deal with burning metals.
Maybe they were more popular when VW Beetles were about, with their magnesium alloy engines. I wasn't such a rare sight, burnt out along the highways.
I've never machined Mg, could it catch alight with heat build up?

Jordan

Originally Posted by simonl

Hi Jordan.

Dont forget electrity is not considered a class of fire as such thats why its represented in parentheses (E). Its a hazard. Once you remove the hazard (ie isolation) then the class of is whatever is burning.

Also you left out a class of fire in your list- class D flammable metals

Cheers

Simon

Originally Posted by nadroj

Hi Simon,
I left the parentheses out as they would have needed explanation, which I didn't have. Thanks for that.
I didn't know about the "missing" class D, not in the RFS pocket book, probably don't expect to deal with burning metals.
Maybe they were more popular when VW Beetles were about, with their magnesium alloy engines. I wasn't such a rare sight, burnt out along the highways.
I've never machined Mg, could it catch alight with heat build up?

Jordan

Hi Jordn,

Well until recently I would have thought machining magnesium would have been a very risky activity. A few months back I bought a Hercus No.3A T&C grinder from an engineering workshop in Tullermarine and one thing he did there was make custom racing wheels for the Super cars. He machined them out of solid billets of magnesium. He showed me one and I was able to pick it up with one finger! I asked him if it was dangerous and he said it's all in the house keeping. Keep the area clean and tidy and all is good. He may have taken other precautions I'm not sure but it didn't seem an issue to him. His workshop was indeed spotless and he seemed like a very good operator so I guess it's not a dangerous as I would have thought. I won't be machining magnesium any time soon though!

There are quite a number of metals that burn but they are very rare to come across on a daily basis. Magnesium probably being the most common but then theres Lithium, Sodium, Potassium, Rubidium, Caesium etc. If you look at the periodic table you will see that these are the group 1 elements. Group 1 and group X11 are the most reactive of all elements in the periodic table. Group 1 are mostly metals while group X11 are mostly gases. They are most reactive because they very easily give up and electron (group 1) or take an electron (group X11) to form a complete electron outer shell to become a stable configuration. Group X111 elements (Helium, Neon, Argon, Krypton, Xenon etc) are the most stable as they already have a complete outer shell configuration. These are called the noble gases.

Back on topic, Iron undergoes oxidation in air (rust) and the process is an exothermic reaction (produces heat) but it's so slow that it's not noticeable. Aluminium will also burn in air under the right conditions. Oxygen has a lot to answer for!

Sorry I think I got carried away. Science rocks!

Simon

.
Thanks everyone for a most informative thread.

And, ... probably like most here who read the thread, and who have a dry chemical extinguisher in the workshop, I gave mine a good thump and visual check.

I think I will buy a fire blanket.

Anyone who wants to learn up on chemistry should read "Uncle Tungsten", by Oliver Sacks.
Subtitled "Memories of a Chemical Boyhood", the author has managed to make a fairly dry subject into a fascinating read, even including the Periodic Table.

Jordan

I didn't know that about fire blankets Karl, but what you've said makes sense and correlates with what I've seen with my own. As pointed out by others I guess it depends a lot on just how much heat was involved as to whether it can be reused.

I'm sure you're quite correct regarding the correct procedure for operating a fire extinguisher, and it's interesting to now know the differences in operating and the effectiveness of dry powder v the BCF (Halon) we use at work. However it always makes me laugh a little when people get hung up on the class of fire extinguisher. Great theory! We do an annual emergency procedures training and testing day for work, and for years one of the questions invariably asked would be what class of fire can you not use BCF on? Great question! Now the real world. You're in an aluminium cylinder half way to outer space with a fire on board, you realise it's a "burning metal" type fire, so the BCF isn't effective. Great, now what? Do you just stand there and watch the thing burn? They finished up changing it to tell us to discharge it anyway it's just that it may not be as effective. It only took about 20 years for common sense to prevail. ... something I suspect there's a shortage of these days Unlike commercial buildings with several choices, I suspect many domestic situations will be the same as we face in an aircraft, all the theory in the world is great, but the chances are most houses will only have one type of extinguisher, and if I'm ever faced with a fire again for real, I'm going to dump the nearest dry chemical fire extinguisher, plus any others I can find, on it without hesitation, and argue the point as to whether it was the "correct" one with the insurance company after the fact. 'cos that one type of extinguisher is all I've got!!!

In regard burning metals, I'd suggest not to be lulled in to a false sense of security about what we're machining. Here's a video of aluminium powder burning


Even a pile of steel chips we'd commonly find in the bottom of our chip trays I'd expect would burn very well when covered in cutting and lubrication oils. It's one reason I try to keep my chip trays reasonably chip free at day's end and ALWAYS clean them out before going to work. A simple house keeping precaution, but figure it removing as many fuels as possible doesn't seem such a stupid idea.

A very good and timely thread BTW!

Aluminium powder (Fuel) and ammonium perchlorate (Oxidizer) are used in solid rockets like the boosters on the space shuttle
Nano Alumiuum powder and Ice powered rockets have been tested and the look like they work. Ice is used because it breaks down into oxygen and hydrogen for a bit of extra boost.

I also agree about the Uncle Tungsten book, its a ripper.

Reusing a fire blanket is not as bad as keeping a partially used extinguisher, but if it's saved your bacon once, why take the risk for the saving of a new blanket?
Steel wool burns beautifully and hot too. In a previous workplace, we used to use old magnesium chainsaw and motorbike parts to get the wood heater going on a cold morning. Good job they did too.
One of the best solutions for burning metal is a bucket of earth dumped on the fire, which is hopefully small when you first attack it.
Presence of mind is your best ally. Detect the fire early, attack it early and it's an easy task. In the case of a house fire, if you close all doors/windows upon your retreat and contain the fire to a room, then probably less than 50L of water, (which then becomes 85,000L of steam), would extinguish the fire, but if you left the doors open and allow the fire oxygen, then it will probably become a "surround and drown" with tens of thousands of litres of water used to extinguish the smoking ruins.
One word on fire/extinguishers is that you must isolate the energy source (electricity) and remove the heat or you will most probably get a re ignition and make sure that you stand by for a good period to ensure that the fire is actually out.
How many remember the fire triangle HEAT FUEL OXYGEN? Remove one or more and there is no fire. Well, it's now become the fire tetrahedron. HEAT FUEL OXYGEN CHEMICAL REACTION. Dry chems work by removing the OXYGEN and inhibiting the CHEMICAL REACTION, that is why you must then follow up and remove the HEAT (or the electricity which created the heat) or the FUEL to properly extinguish the fire.
Finally, don't be afraid to call 000, even if you believe you have extinguished the fire. Insurance companies really do prefer that your local Brigade attends, verifies the fire extinguished and investigates the cause etc. It will make your life much easier if you need to make a claim I can assure you.

Originally Posted by Karl Robbers

. . . . then probably less than 50L of water, (which then becomes 85,000L of steam), would extinguish the fire, . . . . .

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.

I worked in a machine shop that had a large metal container on wheels marked "For Magnesium Fires only", this container had a shovel clipped to side and was full of Asbestos Powder and was set up near the lathes for quick response. I never saw it used, because we did not have a magnesium fire, and it disappeared some time in the mid 70's. We did have a couple of magnesium fires years later which were quickly put out with the appropriate extinguisher.

Well I just spoke to someone who services fire extinguishers and who has worked in that industry for a number of years. Apparently the vaporising liquid extinguishers are quite expensive. A 3Kg retails for around $650. I suggest sticking with a dry powder and just hope to never have to use it, BUT use it if needed! Cheers, Simon