An operator began preparations for a cleaning run, and was unaware that a maintenance task to calibrate a pressure transducer was scheduled to also take place that morning. The calibration required a break on a hydrogen line in order to install a Measuring and Test Equipment (M&TE) gage, which was used in the calibration. At the time the operator was informed of the calibration, the cleaning run procedure had been initiated but the actual cleaning had not yet begun. A discussion between his supervisor and the facility maintenance coordinator resulted in a decision to proceed with the maintenance task and suspend the cleaning run until afterwards.

The operator evacuated the hydrogen line and the hydrogen cylinder was valved out. The maintenance work package procedure had view more