What safety device is generally used on an oxygen cylinder?

• A. Fusible plug
• B. Check valve
• C. Pressure safety disc
• D. Spring-loaded plug

Answer: (C)

Safety devices on oxygen cylinders are there to vent gas if the pressure inside gets too high, especially if the cylinder is exposed to heat. A pressure safety disc fits this purpose perfectly because it is a frangible disc built into the cylinder valve that ruptures at a predetermined high pressure, releasing gas and preventing a dangerous overpressure condition. This is specifically designed for oxygen’s safety needs.

A fusible plug is more associated with acetylene cylinders, where a plug melts at elevated temperature to relieve pressure. A check valve prevents gas from flowing backward into the cylinder but does not relieve overpressure. A spring-loaded plug isn’t the standard safety device used on oxygen cylinders. So the pressure safety disc is the appropriate choice because it provides a reliable, rapid relief path for excess pressure.