In what circumstance must the gas supply to the torch be completely shut?

The gas supply to the torch must be completely shut off if hot work will be discontinued for one hour or more to ensure safety and mitigate any risk of fires or explosions. This practice aligns with safe operational protocols in torch operations, as leaving the gas supply on could lead to accidental gas leaks or ignitions if flammable materials are present. By shutting off the gas supply, we eliminate the potential hazards associated with an unmonitored gas supply when the torch is not in active use, especially during periods of inactivity that exceed one hour. This precaution is critical for maintaining a safe working environment during hot work operations.