How to Clean Fire Extinguisher Residue After a Fire

Fires can be devastating, but prompt action with a fire extinguisher can prevent extensive damage and save lives.

According to the latest National Fire Protection Association (NFPA) data, portable fire extinguishers are highly effective at controlling small fires. However, they can leave a significant mess that may cause additional damage if the excess residue is not cleaned promptly. This article will offer guidelines for cleaning fire extinguisher residue and address common safety concerns associated with the process.

Types of Fire

To know which fire extinguisher to use, you must first know what type of fire you are dealing with. The following are the five classes of fires as classified by the NFPA.

• Class A: Fires involving ordinary combustibles such as wood, cloth, or paper
• Class B: Fires involving flammable liquids such as gasoline, oil, or grease
• Class C: Fires involving electrical equipment
• Class D: Fires involving combustible metals
• Class K: Fires involving cooking appliances, grease, and oils

It is crucial to use the correct type of fire extinguisher for the specific class of fire. Using the wrong type could cause the fire to spread or reignite.

Guide to Clean Up Fire Extinguisher Residue

The method for cleaning fire extinguisher residue depends on the type of extinguisher used. In the following sections, we will explore the different types of fire extinguishers and guide you through cleaning the residue from each one.

1. Cleaning Dry Chemical Fire Extinguisher Residue

Dry chemical fire extinguishers are the most common type and are effective against Class A, B, and C fires. They use firefighting agents such as mono ammonium phosphate, sodium bicarbonate, and potassium bicarbonate. The residue from the dry chemicals in dry chemical extinguishers can be corrosive, especially to metals, and should be cleaned up promptly.

• Before you start, wear gloves, masks, and eye protection to avoid direct contact with the residue. Also, open windows and doors or use fans to ensure good ventilation.
• Start by removing as much of the dry chemical residue as possible. You can use a vacuum cleaner with a HEPA filter, which captures fine particles and prevents them from being recirculated into the air.
• For stuck-on residue, spray with a 50/50 mix of isopropyl alcohol and warm water. Allow the solution to sit for several minutes, then wipe with a damp cloth.
• To neutralize sodium bicarbonate and potassium bicarbonate residue, apply a solution of 98% hot water and 2% vinegar. After a few minutes, wipe the area with a damp cloth.
• For monoammonium phosphate residue, use a paste of baking soda and hot water. After several minutes, wipe the area with a damp cloth.
• Finish by washing the affected area with mild dish soap and water, then rinse thoroughly. Use fans to expedite drying.
• Wash dishes, cookware, or clothing with dry chemical fire extinguisher residue as usual in the dishwasher or washing machine.

   

2. Dry Powder Fire Extinguishers

Another type of dry chemical fire extinguisher is the Class D dry powder extinguisher, designed explicitly for combating combustible metal fires. These fires often occur in industrial, manufacturing, or laboratory settings where metal shavings or dust may ignite. 

The extinguishing agents used in Class D extinguishers vary based on the metals present but typically include sodium chloride, sodium carbonate, copper, and graphite.

The chemical residue from these fire extinguishers is usually easy to clean, but in some instances, professional assistance may be required. For example, graphite-based powders are sensitive to static charge and can become combustible if airborne, making vacuum cleaning hazardous.

Due to the different agents in Class D extinguishers, it’s crucial to consult the Safety Data Sheets (SDS) before attempting any cleanup.

3. Cleaning Carbon Dioxide (CO2) Fire Extinguisher Residue

CO2 fire extinguishers are suitable for Class B and C fires. They work by displacing oxygen and cooling the fire. These extinguishers leave no chemical residue behind, making them ideal for use on electronics and in clean environments.

Cleaning up the residue of a CO2 fire extinguisher is often more straightforward than that of other types, as CO2 extinguishers primarily leave behind a cold, inert gas without substantial residue. However, depending on the surface and ambient conditions, some residual dry ice or frost could form. Here’s how to clean up CO2 fire extinguisher residue:

• Shut off the power and unplug any electronic equipment in the affected area before attempting to clean it.
• Use a dry cloth or paper towel to wipe away any visible frost, taking care not to touch bare skin with the dry ice.
• For surfaces that are wet or slippery due to the carbon dioxide gas, use a dry cloth and then mop up any remaining water with paper towels.
• If surfaces have visible stains or marks, clean them with a mild detergent solution and warm water. Rinse the area thoroughly and dry it well.
• After the cleanup, ventilate the area by opening windows or using fans to remove any remaining residue.

4. Cleaning Water and Foam Fire Extinguisher Residue

Suitable for Class A fires only, water and foam fire extinguishers douse flames with water or water-based foam. The residue left behind is primarily water and some foam, a powdery residue that can be cleaned up by drying the extinguishing agent and mopping the affected area.

Cleaning up foam extinguisher residue takes more effort than water cleanup due to all the powder and foamy substances involved. Here’s how to effectively clean foam and fire extinguisher dust and residue:

• First, wear protective gear, including rubber gloves, masks, and eye protection, as you would with all types of fire extinguisher residue. Then, use a dustpan or scraper to scoop up the excess foam and discard it into a waste container. Next, use absorbent towels or rags to wipe up as much of the remaining foam as possible, changing the towels frequently to avoid spreading the residue around.
• Prepare a cleaning solution using warm water and mild dish soap. Scrub the affected area using a sponge or a damp cloth to lift any remaining foam residue. After scrubbing, rinse the cleaned surfaces with clean water to remove any soap residue, and use clean towels or a mop to dry the area thoroughly.
• Consider sanitizing the area using an appropriate disinfectant to prevent potential mold or bacterial growth, especially in kitchens or food preparation areas. 
• Finally, ensure the area is well-ventilated to aid in drying and disperse any residual odors from the cleaning agents used.

   

5. Cleaning Wet Chemical Fire Extinguisher Residue

Wet chemical fire extinguishers are designed for Class K fires, which typically involve cooking oils and fats in commercial kitchens. These extinguishers fight cooking fires by creating a thick layer of foam to cut off the oxygen supply to the fire. 

Cleaning up after using a wet chemical extinguisher might require extra effort due to specific handling requirements and the potential for slippery surfaces.

• Begin by ensuring good ventilation in the area and wearing protective gear such as gloves, masks, and eye protection.
• Use absorbent materials such as towels or rags to soak up as much foam residue as possible. Dispose of these materials in a sealed plastic bag.
• Next, mix warm water and a strong detergent to scrub away any remaining residue on surfaces. Rinse the area with clean water and dry thoroughly with towels or a mop.
• Be cautious while mopping wet chemical residues, as they can make the surface slippery. Consider using a cleaning solution with anti-slip properties to prevent any potential accidents.
• Sanitize the area with an appropriate disinfectant to ensure it is safe for use, especially in food preparation areas.

6. Clean Agent Fire Extinguishers: Minimal Clean-Up Required

Clean agent fire extinguishers are designed to tackle fires without leaving any damaging residues, making them ideal for environments with sensitive electronics or valuable items. These extinguishers use gases like Halon, FM200, or Novec 1230 to suppress the fire by interrupting the chemical reaction that fuels it rather than displacing oxygen or leaving behind a solid residue.

Clean agent fire extinguishers are ideal for Class B and C fires but can also be effective on Class A fires in specific configurations.

While most of the gas from clean agent fire extinguishers dissipates into the atmosphere, it’s advisable to clean any areas where these fire extinguishers were used. This helps remove any particulates left by the flames and neutralize smoky odors. Simply wiping down the affected area with a diluted degreaser will suffice.

Tips for Restoring Areas Affected by Fire Extinguisher Residue

• Professional Cleaning Services: Consider hiring a professional cleaning service for extensive residue or sensitive areas.
• Carpet and Upholstery Care: Clean carpets and upholstery with a wet/dry vacuum, followed by a professional-grade cleaning solution.
• Surface Inspection: Check surfaces for any signs of damage or corrosion post-cleanup and repair as needed.
• Regular Maintenance: Ensure regular maintenance of your fire extinguishers and keep your cleanup kit ready for emergencies.

   

When Should You Use a Fire Blanket Instead of a Portable Fire Extinguisher?

In certain situations, a fire blanket may be more suitable to use than a portable fire extinguisher. 

Fire blankets are made of specially treated wool or fiberglass fabric that can smother small fires by cutting off the oxygen supply, similar to how a dry powder extinguisher works. They are particularly useful for quickly containing and putting out fires involving clothing, food or cooking grease and oils, electrical appliances, and small household items.

Fire blankets are also ideal for situations where using a fire extinguisher could cause more harm than good, such as in an enclosed space or near sensitive equipment. They can also be used to wrap around someone whose clothing has caught on fire, providing emergency protection until help arrives.

It’s important to note that a fire blanket should never be used on large or spreading fires. In these cases, it is best to evacuate the area and call emergency services.

Conclusion

Cleaning fire extinguisher residue is vital in restoring safety and normalcy post-fire. By understanding the types of extinguishers, taking necessary safety precautions, and following the proper cleanup techniques, homeowners, fire safety enthusiasts, and property managers can effectively manage the aftermath of a fire. 

Regular fire extinguisher maintenance and preparedness are equally important in ensuring the safety of your space. Remember, a clean and safe environment is the first step towards rebuilding and moving forward. Stay safe, stay prepared, and always ensure your home or business is always equipped to handle emergencies effectively.