How often should pressure relief valves in an oxygen system be checked for functionality?

The correct choice highlights the importance of checking pressure relief valves in an oxygen system before every oxygen recharge. This practice ensures that the valves are functional and can effectively manage the pressure within the system. Regular checks prior to recharging are crucial because the pressure relief valves are designed to prevent over-pressurization, which can lead to failures or hazardous conditions. By verifying their functionality in conjunction with recharging, maintenance personnel can ensure that the oxygen system remains safe and operational.

While other intervals for checking may seem reasonable, the emphasis on checking before an oxygen recharge ensures that any potential issues are caught immediately, thereby enhancing safety when working with high-pressure oxygen systems.