What type of cylinders must be permanently removed from service if they have been involved in a fire?

Cylinders made of aluminum and composite materials are required to be permanently removed from service if they have been involved in a fire due to the potential for structural integrity compromise. Unlike steel cylinders, which may undergo inspections and possible repairs depending on specific guidelines, aluminum and composite cylinders can experience damage that is not externally visible but could compromise their ability to safely contain liquefied petroleum gas. The materials used in these cylinders can degrade under the intense heat of a fire, leading to an increased risk of failure during use, which could result in leaks or catastrophic failures.

This requirement underscores the importance of safety in handling and storing liquefied petroleum gas. The rigorous standards set by NFPA 58 are designed to prevent hazardous situations that could arise from using compromised cylinders. While steel cylinders can often be evaluated and refurbished following a fire, and plastic cylinders are not generally used for LPG, aluminum and composite cylinders represent a higher risk and therefore have stricter removal requirements to ensure safety.