Final answer:
Portable fire extinguishers should be repaired or refilled by trained and certified professionals who are familiar with the specific maintenance requirements of various types of extinguishers. Old extinguishers that used dry-cleaning solvent are outdated and replaced by modern systems that require regulated maintenance to ensure functionality during a fire emergency.
Step-by-step explanation:
Portable fire extinguishers should be repaired or refilled by professionals who are trained and certified to carry out maintenance on these critical safety devices. Various types of extinguishers, such as those using dry-cleaning solvent, foaming plastics, or other extinguishing agents, have specific servicing requirements. The use of dry-cleaning solvent in fire extinguishers is no longer recommended due to environmental and health concerns. Instead, modern fire extinguisher systems use a variety of substances, including water, foam, CO2, and dry chemicals to suppress fires.
It is important to follow the manufacturer's instructions for maintenance, and in many places, regulations govern who can perform this service, typically mandating that it is done by certified personnel or companies. Regular maintenance and proper refilling are vital to ensure that fire extinguishers will function effectively in the event of a fire. Moreover, some fire extinguisher systems include components designed to deal with specific hazards, such as foaming agents that are effective on fires involving plastics.