What must portable fire extinguishers be, regarding their compliance with fire test standards?

Portable fire extinguishers must be listed and labeled in accordance with established fire test standards to ensure they have been thoroughly evaluated for safety and effectiveness. When extinguishers are listed, it indicates that they have been tested by an independent organization to meet specific performance criteria, thus providing assurance to users that the device performs as expected in the event of a fire.

Labeling serves as an important source of information for users, detailing the type of fire extinguisher, appropriate usage, and specific limitations. This not only helps in proper choice during a fire emergency but also promotes safe handling and understanding of the equipment.

The other options, while they might suggest a level of compliance, do not capture the specific requirements set forth by standards such as those from Underwriters Laboratories (UL) or similar organizations that focus on the listing and labeling process as a mark of quality and reliability.