What action should be taken if corrosion is found on a fire extinguisher shell?

When corrosion is found on a fire extinguisher shell, conducting a hydrostatic test and refinishing is the appropriate action to ensure safety and compliance with regulations. A hydrostatic test evaluates the integrity of the extinguisher under pressure, helping to determine if the cylinder can safely contain the extinguishing agent. This test is essential because corrosion can compromise the structural integrity of the shell, potentially leading to failure during operation.

Refinishing the extinguisher involves properly removing the corrosion and applying a protective coating to prevent future rust or deterioration. This maintenance not only prolongs the life of the extinguisher but also assures that it is reliable when needed. It's important to address the underlying corrosion issue rather than covering it up or ignoring it, as proper maintenance is critical for fire safety equipment.

Cleaning the shell only would not address the corrosion, while immediately discarding the extinguisher might be excessive if it can be tested and refurbished. Painting over the corrosion would also fail to resolve the underlying problem, potentially leading to safety risks in the future.