Final answer:
Extra functional fire extinguishers should be provided when others are out for service to maintain proper fire protection in the area. Dry-cleaning solvents and some extinguishers are not suitable for all fire types, like foaming plastics, so correct fire systems choice is critical.
Step-by-step explanation:
When portable fire extinguishers are removed from service for maintenance and recharging, it is important that temporary fire protection is provided. This is often done by placing additional, functional fire extinguishers in accessible locations to ensure that the level of fire protection is not diminished while the original extinguishers are being serviced. Knowing the location of all safety equipment in a laboratory, including fire extinguishers and eyewash stations, is essential for maintaining a safe working environment. It is also important to note that dry-cleaning solvent and fire extinguishers are not recommended for use on certain types of fires, such as those involving foaming plastics, and that appropriate fire extinguisher systems should be selected based on the specific risks present in the environment.