Could Be Fatal

[cabinetman]

There's not much discussion concerning fire prevention, safety, or dealing with those first few moments. I posted this about fire extinguishers few years ago, and thought it would be worthwhile for a reminder.

There's been a lot of discussion concerning shop safety and how to protect ourselves. There really hasn't been too much discussion about fire extinguishers. I can't emphasize enough the value of having one close by. I've always kept one or more in or near the kitchen and garage area, and many in the shop. Knowing how to use one and which ones are for what type of fires is important. I've had a few fires and in a shop area, especially a wood shop, a fire can get rampant in a hurry. Fortunately there were no injuries or loss of property. Here's a short description of the types.

Fire Extinguisher Ratings

Class A Extinguishers will put out fires in ordinary combustibles, such as wood and paper. The numerical rating for this class of fire extinguisher refers to the amount of water the fire extinguisher holds and the amount of fire it will extinguish.

Class B Extinguishers should be used on fires involving flammable liquids, such as grease, gasoline, oil, etc. The numerical rating for this class of fire extinguisher states the approximate number of square feet of a flammable liquid fire that a non-expert person can expect to extinguish.

Class C Extinguishers are suitable for use on electrically energized fires. This class of fire extinguishers does not have a numerical rating. The presence of the letter “C” indicates that the extinguishing agent is non-conductive.

Class D Extinguishers are designed for use on flammable metals and are often specific for the type of metal in question. There is no picture designator for Class D extinguishers. These extinguishers generally have no rating nor are they given a multi-purpose rating for use on other types of fires.

For more details:
http://www.fire-extinguisher101.com/

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[Pappy]

Good information. I would suggest clicking on the link and reading it. (It is fairly short.)

The best choice for home / shop use , imo, is a CO2 extinguisher. It works by both cooling and smothering (displaces the oxygen) and leaves no residue.

Dry chemical (powder) extinguishers are, in many situations, more effective in that they will leave a coating to help prevent reignition. Just be aware that the powder agents used are highly corrosive.

Remember that both dry chemical agents and CO2 work by starving the fire of oxygen. If you use either in a closed area, be able to get out to fresh air imediately.

Probably the most common flammable metal in the home or shop is magnesium. Whe magnesium burns it produces oxygen, thereby feeding itself. The best thing to do is isolate the magnesium and let it burn itself out. It can be safely buried or covered with dirt to contain the fire. I saw several different agents for fighting these fires, most of which formed a crust over the burning metal to contain the fire, a nd none of them worked very well. I have been out of the firefighting game for 20+ years so there may be some new developments.

Metal fires can be cooled to below the flash point with water mist but this is dangerous and should be left to the pros. If cooled too fast the metal will contract rapidly enough to explode and scatter. CO2 comes out of the nozzle at -110 F. NEVER use it on a metal fire!

[leehljp]

I think that some confusion occurs as people wonder - which is best for my home? At least for me. I admit that I don't have an extinguisher but need at least a couple. My problem is that - "I don't know which to get."

The confusion comes in - in that the kitchen is subject to some chemicals, electrical, wood. Anywhere in the house can have the need for two different kinds. My shop is the same way - a place for chemical, electrical and wood.

Do people have one of each type in each place? In an emergency do they know which one to grab?

(I started this about the time Don wrote his, but got sidetracked and didn't finish it until several minutes after Don's was posted.)

[woodturner]

Probably the most common flammable metal in the home or shop is magnesium.

Where is magnesium found? It's not a metal I would have thought would be in a woodworking shop, so I am assuming it is use in something else such as motors, but I don't know what that would be.

[tommyt654]

Thanks for the reminder of this I need to change out the batterys in our smoke detectors as well this week. Our house was built with a sprinkler system installed in the 2 garage areas and I have 2 CO2 style extinquishers in the workshop as an extra precaution, thanks for the info
Tommy

[Pappy]

Where is magnesium found? It's not a metal I would have thought would be in a woodworking shop, so I am assuming it is use in something else such as motors, but I don't know what that would be.

What comes to mind is some of the router bases are magnesium. I think the sole plate on my PC circ saw is also magnesium.

[leehljp]

Where is magnesium found? It's not a metal I would have thought would be in a woodworking shop, so I am assuming it is use in something else such as motors, but I don't know what that would be.

Magnesium is often disguised in metal castings as aluminum - generically speaking. Magnesium is the fourth most common element on earth.

I remember back 30 to 40 years ago, the motor sports world used magnesium wheels because of its strength along with light weight. Then they found out how volatile magnesium could be when the wheels literally scraped the concrete walls, or in crashes.

ANOTHER volatile combination is at the grinder in a shop. When steel and iron are ground and the dust flies back and collects and builds up, and then Aluminum is ground and the dust flies back and mixes, a deadly combination has just been formed. The next time Steel is put to the grinder and a spark gflies back, the aluminum and steel combination can ignite in a very high temp and intense flame.

Part of the intensity of the Twin Towers heat was from the aluminum of the aircraft and steel frame of the building combining at points, igniting and causing a much higher temp flame than what normally would have been expected. Without the knowledge of this "thermite" type of fusion of metal and the reactionary action, some conspiracy theorists ran rampant.

[cwsmith]

Thanks for the great information, it's always best to be reminded and to keep ourselves up to date.

I keep a "Full Home" rated A-BC extinquisher here at the bottom of the stairs where it's easily accessable for both the shop and kitchen. But I really should have at least one at both locations, I'm sure.

Our biggest concern has always been with electrical, and we have gone to some expense and effort to ensure everything is up to code and never overloaded in any way.

CWS

[chopnhack]

ANOTHER volatile combination is at the grinder in a shop. When steel and iron are ground and the dust flies back and collects and builds up, and then Aluminum is ground and the dust flies back and mixes, a deadly combination has just been formed. The next time Steel is put to the grinder and a spark gflies back, the aluminum and steel combination can ignite in a very high temp and intense flame.

When you mention steel, its a little misleading imho - thermite reactions concerning iron are usually of iron oxides - i.e. rust - there has to be sufficient oxygen to create and sustain the thermitic reaction. I haven't experimented with steel and aluminum to refute you outright, however, I don't think there is much of a risk at your grinder. It would be wise to clean up the debris so that it doesn't get in your eye though!

[durango dude]

I keep an ABC extinguisher on every one of our 3 levels.

They run $40-50 each - but they're a decent precaution.

I refresh one each year (so they hang around 3 years)

First one is right at the entrance to the garage.
Second one is right outside the kitchen
Third one is right outside the laundry room.

I noticed not long ago that fire extinguishers are getting hard to find - and am totally at loss why that would be the case.

My local HD stocks 2-3 different extinguishers, but only has a dozen or so on-hand. Same for the local Wally world.

Near as I can tell --- people aren't buying them, so stores aren't stocking them (a bad situation, if you ask me).

[leehljp]

When you mention steel, its a little misleading imho - thermite reactions concerning iron are usually of iron oxides - i.e. rust - there has to be sufficient oxygen to create and sustain the thermitic reaction. I haven't experimented with steel and aluminum to refute you outright, however, I don't think there is much of a risk at your grinder. It would be wise to clean up the debris so that it doesn't get in your eye though!

I am not going to argue with you out right but I do remember a discussion of this a couple of times over the past 15 years on this forum and on another forum before this one. There were links to shop fires that were started by this very thing and some kind of OSHA regulations, IIRC.

http://en.wikipedia.org/wiki/Thermite
"Metals are capable of burning under the right conditions, similar to the combustion process of wood or gasoline. In fact, rust is the result of oxidation of steel or iron at very slow rates. A thermite reaction is a process in which the correct mixture of metallic fuels are combined and ignited. Ignition itself requires extremely high temperatures."

While the italics is a current quote, it is the same basic statement (some different words) that I remember haphazardly from the causes, no - "Blame" of the the shop fires from long ago links and posts. Blame and cause are not the same here. I do realize that one could be the blame but not the actual cause. It could have been "oily" metals that started and then the thermite reaction escalated it.


STILL to get this back on topic, do we need two or three different kinds of fire extinguishers on hand in a given place?

[leehljp]

I keep an ABC extinguisher on every one of our 3 levels.

Ah, that answered my question. Been gone too long, and haven't been observant enough since returning!

[Richard in Smithville]

One of the things I have learned in fire extinguisher training is to turn the unit upside down and give it a shake every so often as the chemicals will settle in the bottom. Also, ABC's are often the best to have in the home. And make sure you follow c-mans link to how to use an extinguisher. Not mentioned( or I missed it) is to make sure you have an escape route in case you lose control of the fire. Don't trap yourself in!

[cabinetman]

And make sure you follow c-mans link to how to use an extinguisher. Not mentioned( or I missed it) is to make sure you have an escape route in case you lose control of the fire. Don't trap yourself in!

Adding to that it's wise to have drills (practice sessions) with the family members. Don't forget the pets!!

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[chopnhack]

Its a good thread, I too have never really given a thought to fire safety other than common cautions, no oily rags left inside the shop, grinding things outdoors, etc. An ABC fire extinguisher seems to be a very prudent thing to have around.