Fire - your friend your enemy

[irnsrgn]

While replying to the HOW DO YOU STAY COOL thread I got a little carried away at the end on the subject of FIREFIGHTING and decided that it might be a good subject to touch on in another place, so here goes.

FIRE is a common everyday tool that you use as a blacksmith to make the medium you chose to express your artistic talent easy to work, and you most likely have learned to control it to your advantage and make it work for you instead of against you.

FIRE can also be a nasty side effect of your work and most people do not understand the mechanics of suppressing it when it goes wild or gets out of control.

A FIREFIGHTER is a normal person who for some reason or other learns to overcome the natural fear of fire to a certain extent and defies the laws of nature by running into a burning building while other people who seem at the time to have the common sense to run out of a burning building. As you look at your own community you will see that there are few people who will except the challenge of tangling with the BEAST as those in the fire service call fire. The BEAST has to be watched all the time as one lax moment and it will reach out and TOUCH you with serious consequences most times.

Firemen who accept the challenge of taming the BEAST whether full time paid firemen or volunteers go to school to learn how to defeat this monster who some refer to as DRAGON'S BREATH. These people who accept the challenge are paid by you and are provided equipment to do thier job by you in the form of taxes

The FIRE SERVICE is continually finding new ways and new tools to control the BEAST that can affect our lives in so many ways.

---UNDERSTANDING HOW A FIREMAN CONTROLS THE BEAST.-----

Temperatures in a burning structure can be as high as 2000 degrees at the ceiling and progressively cooler at lower elevations and will layer in the area according to temperature. Thus the need for protective gear as an insulation factor to working in this hostile environment.

PROTECTIVE BREATHING EQUIPMENT is also needed in this environment as man made plastics which everything seems to be made out of nowadays produces CYANIDE GAS as a byproduct of its combustion along with CARBON MONOXIDE and other nasty stuff (THE DRAGONS BREATH).

Most people who die in fires are not burned to death as is commonly assumed but are ashpixiated by the smoke and deadly fumes generated from the burning material. THIS IS WHY WE NEED SMOKE DETECTORS IN OUR HOMES, early detection allows us the time to get out in the early stages of a fire and thus increases our chances of survival.

WATER is the firemans tool of choice most often but how it works is a mystery to most. FACT - heat rises, FACT - water boils at 212 degrees except at higher elevations. FACT - it takes a certain amount of heat (BTU'S) to boil water, FACT - water absorbs the heat in order to boil, FACT - water has a cooling effect on most things, FACT - when water boils it converts to steam, FACT - when water converts to steam it expands into a much larger volume as a gas, FACT - 1 cubic foot of water converts into 1500 cubic feet of steam at 1000 degrees, FACT - the air you are breathing now contains 21 percent OXYGEN., FACT - when the oxygen content drops to 13 percent the air will no longer support combustion.

The above FACTS are common knowledge to firemen and they use them to their advantage to suppress or control the BEAST.

Firemen use specially designed nozzles that produce a FOG PATTERN SPRAY with certain size droplets at 100 PSI and 100 GPM flow at the nozzle. It takes another type of FIREMAN called an ENGINEER or PUMP OPERATOR who operates the pump on the firetruck and who is familiar with how much friction loss is in the amount of hose that is leading to the nozzle to give the firemen on the end of the hose the proper tool to do his job properly.

Combining all the FACTS mentioned above the actual mechanics happen to fast to comprehend. The nozzle man will spray the fOG (water coming out of the nozzle not in a straight main stream, but in a fog pattern to make droplets) not on the actual fire (which may not be visible due to smoke) but toward the ceiling where the temperature is the hottest.

What happens very fast is, the fog converts to steam almost instantaneously, this reaction aborbs heat (BTU'S) instantly and thus lowers the temperature drastically, and the expansion of the conversion to steam displaces the available oxygen and thus deprives the fire of 2 of the 3 essentials it needs to live, (heat and oxygen) , the third element is (fuel). These 3 items, heat, oxygen and fuel are known as the FIRE TRIANGLE, remove any one and fire is history so to speak. By removing 2 of the essentials at the same time, firemen are able to quickly KNOCK DOWN the fire and start OVERHAUL (the finishing off of any hot spots) can be accomplished.

--VENTILATION---------------

The Fire Service has come up with what is known as POSITIVE VENTILATION, this is a technique where instead of a fan being place at the top of a door way or at the bottom of a doorway, which only circulates the heat and smoke in a room, the VENTILATION FAN (similar to a high volume crop drying fan) is placed a distance outside a door so that the stream of air covers the whole doorway or opening and blows cool fresh air in to the area instead of recirculating it. This technique has several advantages, it will clear the smoke and heat out of a room in a relatively short time, thus reducing smoke and heat damage. The main advantage is it gives the firemen a cooler environment to work in with more visibility and also makes the source of the fire easier to find.

I know you have most likely observed firemen cutting a whole in the roof of a burning structure. This is a form of Ventilation used to get rid of the smoke and heat which have a tendency to rise to the highest location. What you observe as smoke is actually partly unburned gases just waiting for an ingnition source and oxygen. Just think of the times the unburned gases from your coal forge collected in the pipe leading to your blower and when on the first turn of the crank there is an explosion. This explosion is a form of back draft and if it happens in a structure it can be on a grand scale almost like a bomb going off and scattering shrapnel over a large area not to mention the instant heat generated upon the poor souls (FIREMEN INSIDE). I got blown about 50 feet one time when a backdraft occured and I was standing approx 20 feet outside the door of the structure at the time. Being a Chief has it disadvantages too. In an effort to look out for the welfare of my men, I put myself in danger.


WHAT YOU CAN DO ABOUT THE DANGER OF FIRE IN YOU SHOP.

1. Call the Fire Dept or 911 immediately, you may think you can control the situation yourself, but in the event you can't, people who are trained to will be on their way. Most firemen would rather respond to a false alarm or an incident that was already under control than a raging inferno any time.

2. Have a water hose with a spray capable nozzle handy just in case. A Slack Tub full of water is normally inadaquate and the delivery system is lacking.

3. Several ABC DRY CHEMICAL FIRE EXTUINGUISHERS readily available are a necessity, 5 lb size minimum with a hose for directing the spray is advised. A CO2 extuinguisher is also advised. This will also help you out on the cost of your insurance premium too.

4. Get a TAG to put on each dry chemical extinguisher, and once a month check the gas charge in the extinquisher and turn it upside down several times while shaking it to free the powder up, this is important if you have a power hammer, are close to a railroad or major highway as the powder will have a tendency to pack from the vibration, and pulling the safety pin when needed and no powder coming out is not a surprise you will enjoy. Sign the tag each time you do a check. this will also help with your insurance premium and is required by law in some places.

5. Keep the area around your forge and anvil free of easily combustable material and liquid propellants.

6. Most people never even consider this one, but if you have an overhead door with an opener on it. replace the NYLON EMERGENCY TRIP ROPE WITH A WIRE CABLE. REMEMBER HEAT RISES AND NYLON MELTS AT A RELATIVELY LOW TEMPERATURE. One Fire Dept here in Nebraska lost all their equipment and apparatus because of the inability to open the doors and remove the equipment.

7. When checking several hours after shutting down to see if there is anything burning, Do it with the lights in the building off and use a powerful flashlight to scan the area about chest high. Small tendrils of smoke will show up in the flashlight beam that cannot be seen with the lights on.

I hope this helps you understand the suppression of fire and what to do in the event it happens. I hope that I didn't bore you with this rather lengthy rambling article.

Always play it safe.

[Brian C.]

Well said, Chief.