Wet chemical fire extinguishers are portable fire suppression devices specifically developed to control fires caused by cooking oils and fats (Class F). These extinguishers operate on the principle that the potassium-based liquid chemical discharged during a fire forms a soapy layer (saponification) on the burning oil surface, thereby simultaneously cooling and cutting off oxygen contact. With these features, they provide specialized solutions for kitchen fires occurring at high temperatures.

Historical Development

The emergence of wet chemical fire suppression systems is linked to the increasing fire risk in commercial kitchens during the mid-20th century. Especially with the widespread use of high-temperature appliances such as deep fryers, traditional fire extinguishers proved inadequate in combating such fires.

Although the first portable fire extinguisher was developed in 1819, solutions specifically designed for oil fires only began to be developed in the 1980s. In this period, the first wet chemical systems using potassium acetate solutions were introduced to the market. By the 1990s, standards such as NFPA 17A began to define the technical details of these extinguishers. In Türkiye, the use of these extinguishers has become widespread through the “Regulation on the Protection of Buildings from Fire” and related occupational guidelines.

Operating Principle

Wet chemical fire extinguishers discharge a potassium-based liquid chemical agent when activated. Upon contact with the surface of burning oil, this agent initiates a saponification reaction, forming a protective foam layer on the flammable surface. This layer:

• Cuts off contact with oxygen,
• Lowers the surface temperature,
• Prevents re-ignition of the fire.

The system typically operates with low-pressure air or nitrogen and is refillable after use.

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Areas of Use

Wet chemical fire extinguishers are particularly preferred in the following areas:

• Restaurant and hotel kitchens
• Mass catering facilities
• Fast-food establishments
• Industrial food processing areas
• Mobile food vehicles and ship kitchens

These types of extinguishers are considered essential in environments equipped with deep fryers and grease-based cooking systems.

Standards and Legal Regulations

Wet chemical fire extinguishers must be manufactured in compliance with several national and international safety and quality standards. Prominent regulations include:

• TS EN 3: Turkish and European standard for portable fire extinguishers
• EN 1866: European standard for wheeled fire extinguishers
• Regulation on the Protection of Buildings from Fire (Ministry of Environment, Urbanization, and Climate Change of Türkiye)
• NFPA 10 (USA): Standard for portable fire extinguishers
• UL 8: Technical evaluation standard for wet chemical extinguishing systems

Advantages

• Extinguishes high-temperature oil fires quickly and effectively
• Foam layer prevents reignition
• Easy to use and typically requires less post-fire cleaning
• Leaves less residue on equipment and surfaces compared to powder-based extinguishers

Limitations

• Not suitable for electrical fires (Class C) or flammable liquid fires (Class B)
• Fire type must be correctly identified before intervention
• Requires periodic maintenance and user training

Wet chemical fire extinguishers are of critical importance for fire safety, especially in food preparation and cooking areas. Operating through saponification, these systems are preferred for their rapid response and anti-reignition properties. When procured in accordance with relevant regulations and properly maintained, they offer an effective solution in fire suppression.