In an industrial gas production plant, a leak on a rack of 28 hydrogen (H2) bottles ignited, yet without causing major damage.

A technician moved the rack during filling onto the adjoining external station, since the main station was idle due to nearby works. This movement, even though the hose had remained connected to the rack, caused the bracket to break and an H2 leak to be aimed against the barrel of bottles. The packaging workshop gas sensors immediately detected the anomaly and triggered the workshop’s emergency shutdown: the H2 feed valve was automatically closed. The technician unscrewed the hose to remove the rack from the workshop and transport it to a water tap, in circumventing the building. Along this path, the H2 leak ignited; the technician secured the rack on the ground and sounded the alarm.

The safety crew began by sprinkling the rack with the fire hose, notified external first responders and manually activated the emergency shutdown: H2 production was halted and nitrogen inerting of sensitive installation parts was initiated. When fire-fighters arrived 15 min later, the rack had emptied and the fire had stopped burning. Nonetheless, sprinkling was continued due to the very high temperature of the bottles, whose barrel remained incandescent until an infrared pyrometer became available on-site to evaluate the bottle wall temperature. The entire facility was evacuated. An hour later, with the rack temperature dropping to 25°C, the alarm was lifted.

The formal accident analysis revealed the causes: the configuration of the adjoining filling station did not provide a clear view of the filling hose connection; when the technician moved the rack into storage, since the hose restraint cable had been hooked to the bracket, this movement broke the bracket. The following corrective actions were taken: elimination of the adjoining filling station; visual exposure of the rack/hose connection on the main filling station; addition of a restraint cable fixing ring to the racks; purchase of an infrared pyrometer; and allocation of a zone to isolate defective packaging far from both the production and storage zones.