Anyone exposed to concentrated CO 2 should seek fresh air immediately. Medical attention would be needed for effects that do not resolve quickly or for anyone who loses consciousness. Direct contact of the skin with the pressurized CO 2 can cause frostbite. The damage to the skin can be limited to mild redness, but blisters are also possible. Damage to the eyes can also occur with direct exposure. If you suspect someone has inhaled spray from a fire extinguisher, get them to fresh air immediately.
Exposure of the eyes or skin to any of the dry chemical fire extinguishers should be treated by immediate rinsing of the affected areas.
Karen D. Call or. Case 1. A school nurse called Poison Control because a child sprayed an ABC-rated fire extinguisher toward several students and teachers. Some of them had shortness of breath and coughing while others had nausea, headaches, or irritated eyes. Poison Control instructed the nurse to have everyone get fresh air and to rinse the eyes of anyone with redness or irritation. Poison Control determined that the extinguisher contained monoammonium phosphate and only mild, brief effects were anticipated.
A follow-up call to the nurse was made later in the day, and the teachers and students were all OK. Case 2. A year-old man developed first- and second-degree frostbite injury to his right hand after using a CO 2 -containing fire extinguisher. His hand was in prolonged contact with the CO 2 due to a leaky gas valve. The man needed treatment by a burn specialist. Case 3.
The following product review was noted on an online retailer website for an ABC-rated fire extinguisher. This was my first fire Extinguisher purchase and I had no idea what the powder was so I called poison control and learned the thing had completely discharged in the package. I wish I had read the other reviews more carefully because it looks like this is not an uncommon occurrence with this…" Needless to say, the product only received a 1-star rating!
Outreach materials and educational programs. Extinguisher basics. Evacuation plans and procedures etool. The most common agents used in dry chemical fire extinguishers are monoammonium phosphate and sodium or potassium bicarbonate. Time is of the essence when this type of extinguisher is used because these powders can be corrosive to metals and can lead to further damage if not cleaned up quickly.
Any electrical contacts with residue on them should be cleaned with an electrical contact cleaner, which is typically a compressed air canister containing a cleaning agent that evaporates quickly, such as isopropyl alcohol.
It is always a good idea, if possible to first shut down the ventilation system in the area to be cleaned to avoid resuspending the powdery residue. It may be tempting to vacuum it up. But before you do, you need to know specifically what type of dry chemical agent was used. Monoammonium phosphate fire extinguishers are used to put out Class ABC fires. This type of residue must be cleaned by hand because it can irritate the skin and eyes if resuspended in the air with a vacuum cleaner.
If this type of extinguisher was used, you can remove residue from the floor by wet-sweeping or sweeping with a dust suppressant. Monoammonium phosphate residue on surfaces should be wiped away with a clean, dry cloth or brush. According to a study , soot erasers were also found to be effective for cleaning dry chemical residue on some types of materials. Soot erasers are sponges made of natural rubber that can be used to lift away dust, dirt, and soot from dry surfaces without getting it wet.
For surfaces that can be safely wet-washed, a cleaning paste made with equal parts baking soda and hot water can be used. Once applied, the paste should be allowed to sit on the surface for a few minutes before wiping it away with a damp cloth. Residue that has hardened or adhered to surfaces can be cleaned with a solution of isopropyl alcohol and warm water, which will help to break down the silicone used in this type of extinguishing agent.
Sodium and potassium bicarbonate residues are not as caustic as monoammonium phosphate residue. Given this, they can be safely removed with a vacuum equipped with the high-efficiency particulate air HEPA filter.
Bicarbonate-based residues on surfaces can be cleaned in the same manner as monoammonium phosphate with a clean, dry cloth or brush. For surfaces that can be safely wet-washed, an effective cleaning solution for these types of residue can be made by adding approximately three ounces six tablespoons of vinegar to a gallon of hot water.
The extinguishing agent used in Class D dry powder fire extinguishers will vary based on the specific types of metals found in the setting they are used to protect but will usually contain one of the following:. Some of these residues will clean easily, while others may require the assistance of professionals who are equipped to address the specific requirements of each. Graphite-based powders , for example, are sensitive to static charge and can become combustible if airborne making it dangerous to clean with a vacuum.
Class K wet chemical fire extinguishers are used in commercial kitchens to fight cooking fires. These extinguishers use a wet mixture of alkaline chemicals such as potassium carbonate, potassium acetate, or potassium citrate that turns into a foam, which blankets the fire depriving it of oxygen. Because this type of extinguisher is used primarily in commercial kitchens and around cooking appliances, one of the most important steps is to turn off all power to any equipment prior to cleaning it.
Make sure everything is completely dry before turning any power back on for any appliance. Residue from Class K extinguishers usually clean up well with hot water and soap. Do not spray the foam with water as that will only create more foam, making a bigger mess. Indeed, bromine and chlorine atoms are released as halons decompose in the heat of the fire, establishing a catalytic cycle involving HBr and HCl; the cycle converts active hydrogen atoms to stable H 2 molecules, breaking the chain reaction.
Manufacturers have introduced new families of chemicals containing no chlorine or bromine, called hydrofluorocarbons HFCs ,that have physical properties similar to the halons and no ozone depletion potential.
HFCs extinguish fires in a manner similar to CO 2 or N 2 --by absorbing heat and reducing the concentration of oxygen. The need to find halon replacements remains. Researchers are actively pursuing diverse materials--including iron- and phosphorous-containing compounds and hydrofluorocarbons--with the ability to inhibit flames. They are also developing better means of discharging more conventional chemicals, such as H 2 O, N 2 and CO 2.
For example, one idea is to use a solid propellant to generate an inert gas mixture--an approach identical to the systems in car air bags. Such a system, when activated, would extinguish a fire just as one blows out a candle. Newsletter Get smart. Sign up for our email newsletter. Already a subscriber? Sign in. Thanks for reading Scientific American.
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