All flammable solids are readily ignitable; ignition sources should therefore be isolated and heat sources should be removed. Active cooling will further reduce the likelihood of ignition. If water is used, it will have the additional benefit of increasing water content, raising the ignition temperature. However, this action needs to be balanced against the potential of generating polluting water run-off.
The use of water should also be carefully considered as some flammable solids will react with water producing heat or, in the case of water-reactive material, flammable gas or flame. Additional considerations in these cases are:
- Introducing water into a container of water-reactive material may cause an explosion
- Water may be needed to cool adjoining containers to prevent them rupturing (exploding) or the fire spreading
- Water may only be effective in controlling a water-reactive material if it can be applied at a sufficient flooding rate for an extended period
- The products from any reaction with water may be more toxic, corrosive or hazardous than the products of the fire without water applied
- When responding to an incident involving water-reactive materials, fire and rescue service personnel should take the existing conditions into account, such as precipitation, wind, location and accessibility to the incident, as well as the availability of agents to control the fire or spill
Once ignited, extinguishing media must be selected carefully as some substances within this group require specialist extinguishers (for example, metal powders).