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Thursday, March 18, 2010

Survival Fire Safety, by Mr. F.

In our preparations, we’ve all made an in depth survival plan.  We have stocks of food items and a means to hunt or grow more.  We know where we’ll get water and how to treat it and have solutions for cooking, heating and lighting.  Perhaps some will operate gasoline or propane-run electric generators and some may distill alcohol or use wood gasification for fuel.  We also have adequate supplies of medications, vitamins and first-aid items.  We’ve thought of everything, planned for any contingency.  Right?

What about Fire Safety?  Our plans mostly or entirely rely on fire for cooking, heating and lighting.  Do you have working fire extinguishers or another plan to deal with a fire if one erupts?  If you are planning to use a generator it needs to be properly wired to prevent fire.  And what about your fuel storage?  Is it a hazard?  After all, if services have deteriorated to this point, the local fire department isn’t coming either.

Of all aspects of our daily life, Fire Safety is most commonly overlooked.  The second step to mitigating any safety hazard, after removing the process entirely if possible, is to engineer out the hazard.  Today, this is done for us in the form of model building codes, UL listings and other industry standards.  Not surprisingly, it isn’t forefront in our minds.  But when SHTF, we’ll be trading our electric lights for kerosene lamps and candles, electric ranges for camp stoves and wood fires.  Many things will be home-built or improvised from available resources.  Have we already, or will we, engineer in those safeguards?

The Science of Fire

To understand fire potential, and extinguishment, it is important to understand the dynamics of a fire.  Some of you may recall learning about the “Fire Triangle” in school.  The theory being that combustion occurs when all three components (oxygen, fuel and heat) are present, and removing one or more will extinguish the fire.  While this is a simplistic approach, it makes an appropriate foundation to start with.
First off, this means that the fuel and oxygen components must attain proper geometric distribution or fuel to oxygen mixing.  This usually requires that the fuel, though it may be in a liquid or solid form, must be heated until it vaporizes.  This is where heat comes into play.  “Flammable” means that it will vaporize at temperatures below 105 degrees F and generally includes liquids such as gasoline, alcohol, propane, etc.  “Combustible” refers to fuels which vaporize at temperatures greater than 105 degrees F, thus requiring more heat input for the combustion process to occur.  This is also why it is harder to start a campfire in the dead of a Canadian winter than summer in west Texas.

As a fire burns, the combustion reaction produces large amounts of energy in the form of heat.  This in turn becomes the heat necessary to sustain and/or grow the fire.  The hotter the fire, the more fuel that becomes available and the more rapid the fire’s growth. The only limitation now is the available air. It is important to note, however, that not all fuels need to be in vapor form.  Fine dust particles, when airborne in high enough quantity, can attain the proper mixing with oxygen to burn quite rapidly.  This is important for anyone with bulk storage of grains, coal, sawdust and even dusty hay.
The oxygen, or oxidizing agent, in the context to which we are concerned with comes from “standard” atmospheric air – roughly 20% oxygen, 79% nitrogen, etc.  As the fire burns, hot combustion gases expand and rise in a superheated plume.  As these gases rise, fresh air is drawn into the fire at the base, heated, consumed in the fire and again released upward.  This is what is referred to as convection currents and one reason why you aim a fire extinguisher at the base of the fire. Also note, however, that in some instances such as with gunpowder, no outside oxygen is required for combustion.  Some chemicals, such as nitrates, contain sufficient quantities of oxygen within the molecules, and are easily released during the combustion process.  These burn rapidly and are difficult to control.

Okay, a fire just broke out!  Now what do we do?  First, we need to know what classification of fire it is (that is to say what materials are involved).  This is important so we can determine the proper method of extinguishment. 

Class A Fires
involve “ordinary” combustibles such as wood, paper, cloth, etc.  This is the most common fire you can expect and will most likely occur from a campfire that got out of control, a lantern getting knocked over, a lit candle or some other similar incident.  A little care can go a long way here.
Water is going to be the best means to put out a Class A fire but it’s likely to be a precious commodity.  Snow is another excellent media since it is also very effective at blanketing the fire.  If it is small, you can also try smothering it with a blanket or jacket but make sure there is no flammable liquid involved (guarantee you’ll set the blanket or jacket on fire if there is).  In the case of a small to medium fire outdoors, sand or soil shoveled onto the fire is also effective.  However, sometimes it may be best to simply let the fire burn itself out while you prevent it from spreading.

Chimney Fires can creep up unwittingly.  Unburned volatiles called creosote are given off primarily due to green/wet wood, low temperature fires and insufficient airflow.  This creosote builds up until it either blocks the flue or is ignited by a hot fire.  If a fire occurs, immediately close all inlet vents on the stove to smother the fire.  If it is an open fireplace, extinguish the fire below then carefully try to close the damper if you can.  Do not attempt to cover the chimney but do try to water down the roof if possible.  There is otherwise very little that can be done for a chimney fire.  Water sprayed into the flue will likely crack the flue liner.  Even the extreme temperature generated is likely to cause damage to the chimney.  Damaged flues and chimneys drastically increase the likelihood of a structure fire.  It is best to take every precaution to avoid a chimney fire. [JWR Adds: Chimneys should be cleaned at least once per year!]

Class B Fires
involve generally flammable liquids such as gasoline, kerosene, paraffin, alcohol, etc.  These pose a great risk because they ignite easily and spread quickly.  Accumulated vapors can ignited with the smallest spark, even static electricity.
If you encounter a flammable liquid pool fire, do not use water.  Remember, most of the flammable liquids we will be using are hydrocarbon based and float on water.  Application of the water will cause ripples in the fuel, causing a flare up as well as spreading the fire.  Flammable liquid fire must be extinguished by smothering.  This is best accomplished by dry chemical of foam fire extinguishers though small fires in containers may be carefully covered.

| Now let’s say you are refueling a hot generator and it flashes over.  You now have flames coming out of the fuel tank as well as the gas can.  Get away!  It is important to keep your distance as explosion or eruption is possible.  This is a bad situation and there is little you’re going to be able to do.  A pressurized hose could be used to cool surfaces but at the risk of overflowing the tank or can, thus spreading the fire. In the event of a leaking propane line that catches fire, shut off the gas at the source if it can be done safely.  It is unlikely that anything else you try will be successful and even if it is, you’ll be releasing raw fuel that is likely to re-ignite.

Probably one of the most common and dangerous fires in this class is the grease fire.  This generally occurs from superheating animal fats or vegetable oil and also applies to paraffin.  Again, do not use water.  Find something to cover it with, such as the lid to a pot if you are cooking.  The next step is to do nothing.  That’s right, don’t touch it.  Let me repeat that.  Do not touch it.  Don’t even think about.  You see, as oil, grease or paraffin burns, its’ auto-ignition temperature decreases.  That means that if any air is introduced, it will flash over again unless it has cooled sufficiently.

Class C Fires
involve energized electrical components such as wiring, motors, generators, etc.  In this case, the ignition source is the electricity and the fuel is usually the wiring.  The first step in this situation is to kill the electricity – trip the disconnect, turn off the ignition, shut down the generator, what have you.  Now it is simply a Class A or Class B fire.  DO NOT use water around live electricity.

Class D Fires involve metals, such as sodium, magnesium, aluminum, etc.  These may be found in some fire starters and flares as well as around metal grinding and cutting.  It is possible for two metals, along with a catalyst, to ignite.  Such fires burn rapidly and extremely hot.  However unlikely it is that you will encounter such a fire in a survival situation, this is one you can’t affect without specialized firefighting equipment.

Fire Extinguishers are an indispensable safety item for every household.  Each extinguisher will be labeled for the class of fire and fire size it is capable of being used on.  There are several styles available so familiarize yourself with how yours operates before it is needed.  There are also a number of different extinguishing agents so choose wisely.  Water and water based foams will freeze and the powders used in dry chemical types wreak havoc with electronics.  Do you homework. They also require some regular maintenance.  For instance, dry chemical powders need to be “fluffed” every so often to keep them from caking.  This can be accomplished by turning it upside down and hitting the bottom with a rubber mallet.  And also check to make sure the bottle is free of rust or other mechanical damage.  I recall one incident in which a woman intended to operate a fire extinguisher on a small fire.  However, the bottle was severely rusted and when she “charged” it by firing off the supplied air cartridge, the top blew off and killed her. Also, with the exception of the old “Indian fire pumps”, it’s unlikely you’ll be able to refill them.

Doubtless, the most fearful fire of all is one that upon your person.  In the event that your clothes become involved, don’t run.  STOP, DROP and ROLL to smother the fire.  If you see someone else on fire, this is where  your time on the high school football team comes in handy.  Grab a blanket, preferably wool, and tackle them (albeit gently).  The goal is to get them on the ground and covered with the blanket, smothering the fire.  Depending on the circumstances and clothing involved, there will likely be some first aid required.

Up in Smoke

Aside from the inherent dangers of fire itself, combustion by-products may pose an even greater hazard.
In complete combustion of organic materials, where adequate free air exists for the fire, carbon dioxide and water are produced.  Carbon Dioxide (CO2) is a colorless, odorless gas which, being heavier than air, collects in low areas.  An increase of only 2-3% CO2 in the air we breathe can result in impaired memory, loss of fine motor skills and weakness.  Higher concentrations can cause unconsciousness and death.  If you find someone a victim of CO2 exposure, ventilate the area.  Do not go rushing in and become a victim too (you won’t do them or yourself any good like that).  Remove the victim to an area with fresh clean air.  In some cases, the victim may require further medical treatment my trained personnel.

If the fire is starved for oxygen, then carbon monoxide (CO) is produced.  Again, CO is a colorless, odorless gas, but it is even more dangerous.  Generally, CO exposure causes a feeling of sleepiness in the victim, but also nausea, headaches and vertigo.  Once the victim becomes unconscious, death soon follows.  The complicating factor here is that CO molecules bond to hemoglobin, the oxygen carriers in the bloodstream, preventing oxygen from getting to the cells.  Simply getting the victim to fresh air will not adequately purge CO from the system.  Treatment for CO exposure usually requires 100% oxygen or hyperbaric treatment.

When inorganic materials such as plastic, paint, glue, particle board, wire insulation and other man-made materials burn, there is virtually no limit to the volatile and toxic chemicals that are released.  These can result in serious illness and death very quickly and will almost certainly require medical treatment you cannot provide at your survival retreat.

An Ounce of Prevention

While we want to be prepared to deal with a fire if one starts, our best bet is to “engineer out” the hazard and prevent a fire altogether.
Make sure that lanterns, lamps and candles are placed on a flat, stable surface.  Candles should be in a proper holder or on a porcelain or tin plate with sides to catch melted wax.  An empty tuna can works well for this.  Ensure that all combustibles are kept away and be mindful of shirt sleeves and loose clothing when working with or around such items.  Also, be careful around children and animals (remember Mrs. O’Leary’s cow).

As I said before, chimney fires are best avoided and regular maintenance is the key to preventing them.  This starts with regular cleanings.   If you are burn strictly for heat in cold months, this means at least one cleaning before the burn season and possible more during the season.  If you will be burning regularly for cooking, you’ll probably be using a smaller fire, thus creating more creosote.  Burning hot and staying away from “green” wood or wood heavy with resins such as pines will drastically help reduce buildup. 

There are various products on the market which claim to help with creosote buildup.  These products are simply burned periodically in the fire.  However, while these would likely help, they are certainly no replacement for proper cleaning.  Make sure you have a brush or two of the proper shape and size for each flue.  In a pinch, a bundle of chain on a rope will work for small flues. 

Even as I write this, I received a call from a woman who just had a chimney fire last night.  Today she is trying to make repairs so that it is again safe to burn.  Metal chimneys are expensive but easily replaced if you have spare parts.  However, damage to masonry chimneys is much more difficult to repair.
Take extra care with flammable liquids.  When stored, ensure that they are in approved containers with good seals.  On his 1911-12 journey to the South Pole, Robert Scott left caches of food and fuel.  On the return trip, he found that many of the fuel cans were empty, having leaked at the seals.  The lack of fuel eventually led to their deaths.

Flammable liquids should be stored out of sunlight and in a well ventilated area.  And for God’s sake don’t use anything with a flame around flammable liquids.  Even a flashlight is a potential ignition source.  If you need to have something for light, get a small flashlight with a Class 1, Div.1 rating.  I use ones from Pelican and UA.
Also avoid using gasoline and the like for starting fires.  The accumulation of fumes can have deadly results.  A good alternative is to use gel starting fluid for pellet stoves.  The gel is less volatile and won’t flash or explode like gasoline will.

Also be very mindful of the clothing you wear around or when starting a fire.  Nylon, rayon and the multitudes of synthetic fibers used in clothing today are extremely dangerous.  They ignite easily and melt even easier thus increasing the need for medical attention.  Natural fibers such as cotton and wool are best.
When possible, buy instead of building anything that uses a flame.  This includes lanterns, stoves, burners, incubators, brooders and heaters.  There are also several manufacturers of fire resistance coatings that can be applied to almost anything.

Be careful with outdoor fires, especially when windy.  The last thing you want to do is start a fire that burns your house or shelter down with your supplies in it.  Remember the rule of 3’s?  You can survive 3 hours without shelter, 3 days without food.

Don’t use stoves or flames inside of tents unless both the tent and the stove are intended for such a purpose.
If you are planning to use a wood framed structure for your survival shelter, you may want to think about fire resistance.  A number of manufacturers offer concrete fiberboard siding that is fire proof as well as water, weather and insect proof.  There are also a number of options for roof coverings such as metal, clay and cement fiberboard.

Unless you are competent in electrical wiring, make sure to have everything checked out by a licensed electrician.  If you plan to use an electric generator, use the proper connections and transfer switches.  Don’t try to jury rig this - the shock and fire potentials here are extremely high.
Smokey Bear always said “Only you can prevent forest fires”.  This is essentially true in a survival situation too.  Many of us will be living in somewhat primitive conditions compared to what we are used to.  We need to be vigilant at every moment.  Think Safe, Be Safe.