The Essential Guide to Wet Chemical Fire Extinguishers in Commercial Kitchens

Wet Chemical Fire Extinguishers

Cooking-related incidents are a leading cause of fire casualties worldwide. In the U.S. alone, cooking appliances cause up to 61% of structure fires in eating and drinking establishments.

These fires are classified as Class K or Class F and can reach extremely high temperatures. They also pose a risk of reflashing if not extinguished properly.

This is where wet chemical fire extinguishers come in. They are specially designed to combat these fires by using alkali salts to create a cooling and sealing foam.

Want to learn more? Keep reading for everything you need to know about these extinguishers.

How Do Wet Chemical Fire Extinguishers Work?

Wet chemical fire extinguishers are designed to put out fires involving cooking oils and fats. They are quite indispensable in commercial kitchens and other places where large volumes of oils are used.

These extinguishers spray a liquid agent onto the burning oil or fat. The agent contains potassium acetate, potassium citrate, or potassium bicarbonate. The resulting reaction creates a soapy foam covering the fire’s surface, preventing oxygen from reaching the fire.

This saponification process effectively cools down and smothers the fire. The foam also creates a seal that reduces reflash risk, a common hazard with these fires.

Wet chemical fire extinguishers require specialized training and proper use to ensure effective and safe firefighting. Users must follow the instructions on the label and use the PASS technique to operate the extinguisher:

  • Pull the pin
  • Aim at the base of the fire
  • Squeeze the lever
  • Sweep from side to side

Be sure to maintain a safe distance from the fire (at least 1 meter or 3 feet) and avoid spraying directly into hot oil or fat, as this can cause splashing or boiling over. Users must also know when to stop fighting the fire and evacuate if necessary.

The Benefits of Wet Chemical Extinguishers

Commercial kitchen fires are often dangerous due to the copious use of oils and fats. Worse, you can’t rely on regular fire extinguishers or sprinkler systems to handle these scenarios. Wet chemical extinguishers stand out as an effective option.

They offer distinct advantages for commercial kitchens.

Extinguish Hot Grease and Oil Better

Wet chemical extinguishers use specialty liquid formulas to cool and coat the burning oil rapidly. This creates a soapy film that clings to greasy surfaces while suppressing any sources of fire and oxygen.

This makes wet chemical extinguishers far more effective for handling Class K and Class F fires than alternatives.

Mitigate Fire Contamination of Kitchens

Most fire extinguishers often leave dust residues or waste that you cannot wash away. Additionally, over time, these residues may damage certain equipment, like seals or wire insulation.

However, you don’t have to worry about this with wet chemical extinguishers. They use agents less likely to contaminate valuable stock, appliances, or prep area surfaces.

Reduce Smoke and Unpleasant Odors

Wet chemical extinguishing agents contain special additives that break down oil and fat compounds as they spread. As a result, they produce less smoke and unpleasant smells that linger. This allows for faster recovery and reopening of your commercial kitchen.

Who Needs Wet Chemical Fire Extinguishers?

The answer is simple: if you use large volumes of cooking oil or grease, you need a wet chemical extinguisher. This means any business with a professional kitchen or that fries foods, including those listed below.

Restaurants and Fast Food Chains

Full-service restaurants and fast food chains are prime candidates for wet chemical extinguishers. Deep fryers, grills, ranges, and other cooking equipment can quickly become engulfed in flames.

Regular extinguishers may not be enough to put out the fire. In fact, having a suitable suppression system specially designed for grease fires is an NFPA requirement.

Institutional Cafeterias

Cafeterias, especially those in office buildings, schools, and hospitals, also require these extinguishers. Although they may not serve as much volume as a busy restaurant, they have appliances that still pose a significant risk. Insurance providers expect businesses to have appropriate wet chemical capacity scaled to their equipment use.

Hotel Kitchens

Hotels, motels, and resorts often have commercial kitchens with various cooking appliances that use oil and grease. The risk of a cooking oil fire occurring in a hotel kitchen is high, especially during peak hours when the kitchen is busiest.


Bakeries often use commercial deep fryers or bain maries with hot oils. While the demand may be less intense than in a busy restaurant, the hazards posed by a donut fryer media, for example, is a recipe for disaster. The good news is that a wet chemical extinguisher can provide extra protection in case of a fire.

Installing and Maintaining Wet Chemical Fire Suppression Systems

Fixed wet chemical fire suppression systems are installed to provide extra protection against fires. These systems detect and put out fires before they spread.

The ANSUL R-102 system is an example of a wet chemical system. It works by spraying a special liquid over the cooking area to put out the fire. The system automatically detects fires and can also be activated manually.

The liquid is safe for Class K fires and won’t damage equipment or facilities. To ensure the system works correctly, it needs to be inspected every year by a qualified professional. They will check all parts of the system, including the nozzles and connections.

The detection system, cylinder pressure, and cylinder weight are also checked. The nozzles need to be cleaned regularly to remove cooking grease buildup. Kitchen staff need to be trained on manually activating the system and evacuating the area in case of a fire.

By installing and maintaining a wet chemical extinguisher, commercial kitchens can reduce the risk of fires and keep their staff and customers safe.

Entrust Your Kitchen Fire Safety to Specialists

When it comes to specialized fire protection for commercial kitchens, expertise matters. This is where a reliable fire protection company like Castle Sprinkler and Alarm comes in. Located north of Washington, DC, we ensure full code compliance tailored for your commercial kitchen’s unique risks.

Our team develops and audits response plans, ensuring your staff is always prepared. We also install, inspect, and maintain the right wet chemical fire extinguishers and other fire safeguards. Reach out today to request a service or learn more about how we can help you.

Wet Chemical Fire Extinguishers (FAQs)

How do wet chemical fire extinguishers work?

Wet chemical fire extinguishers are designed to tackle fires involving cooking oils and fats, which are prevalent in commercial kitchens. They discharge a liquid solution containing potassium compounds that react with the oil or fat to form a soapy foam. This foam covers the fire, cutting off the oxygen supply and preventing re-ignition by creating a seal over the fuel source. The saponification process not only extinguishes the fire but also cools the burning oil, significantly reducing the risk of reflash.

What makes wet chemical extinguishers ideal for commercial kitchens?

These extinguishers are tailored for environments where cooking oils and fats are heavily used. Their ability to rapidly cool and cover burning oil makes them superior for handling Class K and Class F fires, which are common in these settings. Unlike traditional fire extinguishers, wet chemical extinguishers minimize damage to kitchen equipment and reduce contamination, making them a practical choice for businesses prioritizing safety and hygiene.

Who needs wet chemical fire extinguishers?

Any establishment that uses large volumes of cooking oil or grease, such as restaurants, fast-food chains, institutional cafeterias, hotel kitchens, and bakeries, should have wet chemical fire extinguishers on hand. These settings face a high risk of Class K and Class F fires, and having the appropriate extinguishing agents is crucial for safety and compliance with fire safety regulations, including NFPA standards.

How are wet chemical fire extinguishers maintained?

Regular inspection and maintenance are vital to ensure wet chemical fire extinguishers remain effective. This includes checking the agent’s level and pressure, ensuring the nozzle and hose are clear of obstructions, and verifying the extinguisher’s overall condition. Training on proper use, including the PASS technique, is also essential for staff to ensure they can act quickly and safely in the event of a fire.

What are the benefits of installing a fixed wet chemical fire suppression system?

Fixed systems provide automatic fire detection and suppression over cooking areas, offering an additional layer of protection. Systems like the ANSUL R-102 automatically discharge the wet chemical agent when a fire is detected, significantly reducing the damage and risk associated with kitchen fires. Regular inspections by qualified professionals ensure these systems function correctly, maintaining safety in commercial kitchens.

By incorporating wet chemical fire extinguishers into their fire safety protocols, commercial kitchens can significantly enhance their ability to respond to and mitigate fires involving cooking oils and fats, ensuring the safety of staff and patrons alike.