a fire watch must be held for at least __________ after completion of welding and cutting.

A fire watch must be held for at least 30 minutes after the completion of welding and cutting operations. This duration is the minimum required by OSHA to detect and extinguish possible smoldering fires that may ignite after hot work is finished. Some guidelines and standards, like NFPA, suggest longer durations in higher-risk situations, sometimes up to 1 hour or more, depending on the risk assessment and site conditions.