Which material are fusible plugs made from, and what is their safety feature?

• A. Plastic; they prevent cylinder freezing
• B. Metal; they melt to release gas at high temperature
• C. Ceramic; they provide electrical insulation
• D. Rubber; they prevent gas leaks

Answer: (B)

Fusible plugs are specifically designed as a safety feature in gas cylinders, particularly in anesthesia and medical gas applications. These plugs are made from a metal that has a low melting point. In the event of a fire or extreme heat, the metal will melt and allow gas to safely escape from the cylinder rather than allowing the cylinder to burst due to increased pressure. This mechanism effectively reduces the risk of an explosion by venting the gas in a controlled manner.

The other materials listed in the alternatives do not serve the same purpose as fusible plugs. Plastic, while versatile, does not provide the necessary temperature response required for safety in high-temperature situations. Ceramic is typically used for electrical insulation and does not relate to the gas release function of fusible plugs. Rubber does not have the ability to melt and provide a venting mechanism; its primary use is in preventing leaks in seals and connections, rather than acting as a safety release at elevated temperatures. Therefore, the correct choice highlights the vital safety role that metal fusible plugs play in preventing dangerous situations during high heat conditions.