Wet Chemical Fire Extinguishers

Wet chemical fire extinguishers are the only type rated for Class F fires — fires involving cooking oils and fats. They are a legal requirement in commercial kitchens, restaurants, cafes, and food service environments under Australian Standards. Available in 2L (home kitchen) and 7L (commercial kitchen) in both standard and stainless steel from $86.90.

How Wet Chemical Extinguishers Work

Wet chemical extinguishers contain a potassium-based solution (potassium acetate or citrate). When discharged onto a cooking oil fire, the solution undergoes a saponification reaction — it reacts with the burning fat to form a soap-like crust over the surface, sealing it off from oxygen and preventing re-ignition. The fine mist discharge also cools the oil rapidly, well below its ignition temperature.

This dual action (sealing + cooling) is what makes wet chemical the only safe and effective agent for Class F fires. Never use ABE dry powder or water on a cooking oil fire — the violent pressure discharge can cause burning oil to explosively splatter, dramatically spreading the fire.

Which Size Do You Need?

Commercial kitchens with multiple deep fryers or large cooking surfaces typically require more than one 7L unit. Under AS 2444, placement and number of extinguishers depends on the total cooking surface area and fire risk level.

Where to Position a Wet Chemical Extinguisher

Mount your wet chemical extinguisher near the exit of the kitchen — not directly beside the cooking appliance. In a fire emergency, you need to be able to reach the extinguisher without moving past the fire. The recommended approach distance for wet chemical discharge is 1 metre from the burning surface.

Wet Chemical vs Other Extinguisher Types

• Wet chemical vs ABE powder — ABE covers Class A, B, C, and E fires but is NOT rated for Class F. Using powder on a cooking oil fire can spread the fire and contaminate food preparation surfaces with residue.
• Wet chemical vs CO2 — CO2 is not effective on Class F fires and will not prevent re-ignition of hot oil. CO2 is the right choice for server rooms and electrical fires, not kitchens.
• Wet chemical vs water — Never use water on a cooking oil fire. The water instantly vaporises on contact with burning oil, creating a steam explosion that projects burning oil in all directions.

Compliance: What Australian Standards Require

• AS/NZS 1841 — Product standard. All wet chemical extinguishers sold in Australia must be certified to this standard. It defines the oatmeal/beige colour band, fire class ratings, and performance requirements.
• AS 2444 — Selection and placement standard. Covers which extinguisher types are required for commercial premises, including kitchens. Applicable to all food service businesses.
• AS 1851 — Maintenance standard. All installed extinguishers must be serviced every 6 months by a licensed fire protection technician. A tag on the extinguisher must record each service date.

For other fire hazards in your premises — electrical equipment, flammable liquids, or general combustibles — browse our full range of fire extinguishers, including CO2 extinguishers and ABE dry chemical extinguishers.

For a complete guide to choosing between 2L and 7L, placement rules under AS 2444, and fire blanket pairing, see our kitchen fire extinguisher guide.

Frequently Asked Questions

Do I need a wet chemical extinguisher at home?

It is strongly recommended for any home with a deep fryer or large amounts of cooking oil. A 2L wet chemical extinguisher is the right choice for a domestic kitchen. While not legally required for residential properties, it is the only type that can safely extinguish a cooking oil fire — ABE powder and water can make an oil fire significantly worse.

What colour band is on a wet chemical extinguisher?

Wet chemical extinguishers are identified by an oatmeal (beige) colour band near the top of the red cylinder, standardised under AS/NZS 1841. This distinguishes them from ABE dry chemical (white band), CO2 (black band), and foam (blue band).

Can wet chemical extinguishers be used on electrical fires?

No. Wet chemical extinguishers are not rated for Class E (electrical) fires. Turn off the power at the switchboard before using a wet chemical extinguisher near electrical appliances. For electrical fires, use a CO2 or ABE dry chemical extinguisher instead.

How often do wet chemical extinguishers need servicing?

Every 6 months, by a licensed fire protection technician, under AS 1851. You should also check the pressure gauge monthly — if the needle is outside the green zone, the unit requires immediate recharging. Keep the extinguisher tag updated with each service date; this is required for compliance in commercial premises.

What is the difference between standard and stainless steel wet chemical extinguishers?

The agent and fire rating are identical. Stainless steel cylinders are better suited to high-humidity environments (seafood restaurants, commercial dishwashing areas, outdoor kitchens) where a standard powder-coated cylinder is more susceptible to surface corrosion over time.