"Maintenance" is a __________ examination.

The term "maintenance" in the context of fire extinguishers refers to a detailed and comprehensive inspection process. This examination is crucial to ensure that fire extinguishers are functioning correctly and are ready for use in the event of a fire emergency.

A thorough examination covers all aspects of the extinguisher, including checking for damage, ensuring the pressure is within the appropriate range, examining the physical condition, inspecting the safety seals, and verifying that all components are working as intended. Regular maintenance is mandated by NFPA 10 to help ensure that these life-saving devices are reliable and effective.

In contrast, a routine examination may imply a less thorough check, focusing only on basic checks rather than a complete evaluation. A visual inspection, while important, typically involves a less comprehensive assessment than what is required for maintenance. A quick examination might not capture all necessary details that could indicate a need for service or replacement. Therefore, the correct answer highlights the necessity of a detailed and careful approach to maintenance in ensuring the effectiveness and safety of portable fire extinguishers.