Wet Chemical Fire

Specifications

1. Type of Fire Classification
   • Class K Fires: Wet chemical extinguishers are specifically designed for Class K fires caused by cooking oils, fats, and greases. These types of fires are not easily extinguished by conventional water or foam extinguishers.
   • Class A Fires: Wet chemical extinguishers are also effective against Class A fires, which involve ordinary combustibles like wood, paper, and cloth.
   • Not for Electrical Fires: Wet chemical extinguishers should not be used on electrical fires (Class C) or flammable liquid fires (Class B) unless the power is cut off, as the solution can conduct electricity.
2. Mechanism of Action
   • Chemical Reaction: When the wet chemical agent is discharged, it reacts with the heat of the fire to form a soapy foam that smothers the fire, cooling the oils and preventing the fire from reigniting.
   • Cooling Effect: The wet chemical agent cools the oil to below its ignition point, effectively extinguishing the fire and preventing the thermal energy from reigniting the flames.
   • Oxygen Deprivation: The foam layer created by the agent deprives the fire of oxygen, which is one of the key elements needed for combustion, leading to the fire being fully extinguished.
   • Prevents Re-Ignition: The foam creates a barrier over the cooking oil that prevents the fire from reigniting, offering long-term suppression until the source is safely contained.
3. Design and Construction
   • Cylinder Material: Wet chemical fire extinguishers are typically made from steel or aluminum, offering durability, lightweight design, and resistance to corrosion.
   • Capacity: Common sizes include 6L, 9L, and 12L. These sizes provide enough coverage for typical kitchen and restaurant environments.
   • Discharge Time: Discharge time typically ranges from 8 to 12 seconds, depending on the size of the extinguisher.
   • Nozzle: The nozzle is specifically designed for a fine mist or jet spray, ensuring an even application of the wet chemical agent over the fire. Some models also include a long hose for better reach.
   • Operating Pressure: Wet chemical extinguishers usually operate at low pressure, which reduces the risk of splattering the burning oils and spreading the fire.
4. Application and Usage
   • Commercial Kitchens: Essential in restaurants, hotels, cafeterias, and catering facilities where grease and oil fires are a constant hazard.
   • Home Kitchens: Wet chemical extinguishers can be used in home kitchens for small-scale protection against accidental grease fires.
   • Food Processing Areas: Wet chemical extinguishers are ideal for food production and processing areas where high-heat cooking oils are used.
   • Mobile Kitchens: Food trucks and other mobile kitchen facilities should be equipped with wet chemical extinguishers to safeguard against cooking oil fires.
5. Advantages
   • Designed for Grease Fires: Wet chemical extinguishers are the best option for fires caused by cooking oils, fats, and grease, making them more effective than water, CO2, or foam extinguishers in these scenarios.
   • Prevents Re-Ignition: The foam layer formed by the wet chemical agent helps to seal the fire, preventing it from reigniting and ensuring that it is fully extinguished.
   • Safe for Kitchen Equipment: Unlike water, which can damage kitchen appliances, wet chemical extinguishers are safer and more suitable for use in kitchens without causing water damage to appliances.
   • Versatility: Wet chemical extinguishers are also effective for Class A fires, which involve ordinary combustibles like paper, wood, and textiles.
   • Easy to Use: Wet chemical extinguishers are designed to be simple to operate, even in high-stress situations, making them essential in busy kitchen environments.
6. Limitations
   • Not for Electrical Fires: Wet chemical extinguishers are not suitable for electrical fires unless the electrical supply has been shut off. These extinguishers can conduct electricity and cause further hazards if used on live electrical equipment.
   • Specialized Use: They are primarily designed for use in kitchens and may not be suitable for industrial or outdoor fire hazards involving flammable liquids (Class B) or electrical fires (Class C).
7. Compliance and Standards
   • BS EN 3: Wet chemical fire extinguishers are required to meet BS EN 3 standards in Europe, ensuring that they are manufactured to a high level of safety and performance.
   • NFPA 10: Wet chemical extinguishers also comply with NFPA 10 standards in the U.S., which outlines the requirements for portable fire extinguishers.
   • UL Listed: Many wet chemical extinguishers are UL Listed, meaning they have been tested and approved for performance and safety in the United States.
   • CE Marked: Wet chemical fire extinguishers in Europe often carry the CE Mark, which indicates they conform to the required health, safety, and environmental protection standards.
8. Maintenance and Servicing
   • Annual Inspection: Wet chemical fire extinguishers should be inspected yearly to ensure that the chemical agent remains effective, the pressure is within range, and no physical damage is present.
   • Recharge After Use: After any discharge, the extinguisher must be recharged with the appropriate wet chemical solution to restore its full functionality.
   • Hydrostatic Testing: Wet chemical fire extinguishers require hydrostatic testing every 5 years to ensure the integrity of the pressure vessel.
   • Servicing: Professional servicing is required if the extinguisher has been discharged or shows signs of damage, corrosion, or loss of pressure.