The number and type of fire extinguishers needed depends on the fire hazard. The fire risk assessment will identify the hazards. The primary purpose of a fire extinguisher is to aid escape from a fire. In some limited circumstances they may be used by a trained person to fight fires in the early stages.
The fire extinguisher should be suitable for the potential fire :-
water
For wood/paper/textile and solid material
powder
For liquid and electrical fires
foam
For liquid fires
Carbon dioxide
For liquid and electrical fires
Fire extinguishers should be located at identifiable fire points at each storey exit and these should be serviced and maintained.
Fire extinguishers will also be needed for those carrying out hot work.