Ideally, which should be used to extinguish a chimney fire?

To effectively extinguish a chimney fire, the use of dry chemical agents is recommended because they can quickly suppress the flames by interrupting the chemical reaction of combustion. Dry chemical extinguishers contain substances that are effective on flammable solids and liquids, which are often present in chimney fires due to the accumulation of creosote and other flammable materials from burning wood or other fuels.

While water is a common extinguishing agent for many types of fires, using it on a chimney fire can have drawbacks. The sudden temperature change can cause thermal shock to the chimney structure, which may lead to further damage or even collapse. Additionally, if the water is applied recklessly, it can cause steam explosions, worsening the situation.

Class A foam might also be used on these types of fires, as it can help to cool and suppress burning embers. However, it is generally considered less effective than dry chemical agents for the specific conditions and materials involved in a chimney fire.

CO2 extinguishers primarily work by displacing oxygen and are less effective when it comes to suppressing solid fuel fires, which are common in chimney malfunction incidents.

In summary, dry chemical is the preferred choice due to its effectiveness in suppressing the combustion process in the materials involved in chimney