It flashes to steam on contact and ejects burning oil violently.

Oil at cooking temperature is far above water's boiling point.

The resulting steam explosion spreads burning oil across the kitchen.

That is the mechanism behind the well-known demonstrations of chip pan fires.

A gaseous agent knocks down the flame but leaves the oil above its auto-ignition temperature.

It then reignites within seconds, which is why sealing and cooling are both needed.

The alkaline agent reacts with burning fat to form a soapy foam layer across the surface.

That layer seals the oil from air and cools it at the same time.

The seal is what prevents reignition once the flame is out.

It is the reason wet chemical rather than any other chemistry is used over cooking equipment.

The foam persists long enough for the oil to cool below its ignition temperature.

Cleanup afterwards is straightforward compared with dry chemical residue.

Because each appliance presents a different surface area, oil depth and flame behaviour.

Fryers, griddles, ranges, woks and char-broilers all need different nozzle types and aiming.

Nozzle selection and position are calculated for the specific cooking line.

Additional nozzles protect the hood plenum and the duct where grease accumulates.

The duct is how a kitchen fire leaves the kitchen, so it is protected separately.

The design is a layout drawing rather than a product specification.

The nozzles are aimed at a layout that no longer exists, and that is the most common defect in this category.

A system protecting the position where a fryer used to be will not work.

Replacing an appliance with a different model changes the hazard even in the same position.

It happens constantly and rarely triggers a review, because it feels like a catering decision.

Any change to the cooking line requires the suppression design to be revisited.

This is worth writing into kitchen equipment procurement rather than leaving to chance.

They shut off gas and electrical supplies to the appliances on discharge.

Removing the heat source is what stops the oil reheating past the foam blanket.

Without it, the appliance continues heating and the fire can re-establish.

Interlocks are part of the system rather than accessories to it.

They are tested functionally rather than assumed to work.

Manual pull stations allow discharge to be triggered deliberately, and they must be accessible on the escape route.

No - grease cleaning of hoods and ducts is separate and is the other half of kitchen fire safety.

A grease-laden duct is a fire path out of the kitchen and into the building.

Suppression protects the cooking line; it does not address accumulated grease elsewhere.

Cleaning frequency depends on cooking volume and type and is often specified by insurers.

Access panels for cleaning are a design feature that is frequently inadequate.

A well-maintained system above a dirty duct is protecting the wrong part of the problem.

Periodic inspection and service by a competent contractor, including nozzle condition, agent quantity, detection links and interlocks.

Nozzles carry blow-off caps that keep grease out and are replaced at service.

Fusible link detectors become coated with grease and are replaced on a schedule.

Agent cylinders are weighed or pressure-checked depending on the system.

Interlock operation and manual pull stations are tested functionally.

Intervals and competency requirements are set locally and are frequently also an insurance condition.