Malfunctioning in a hydrogen refuelling station

Event

Event ID: 404
Quality: 2
Description: At a refuelling station for buses, the first dispenser had been taken out of operation, because leaking (see HIAD event 403). Another dispenser was being used. Fuelling was taking too long and was very slow. The producer was called and it was found that the solenoid valves were not opening correctly due to a lack of compressed air.
Event Initiating system: Non-Hydrogen System Initiating Event
Classification of the physical effects: No Hydrogen Release
Nature of the consequences: Near Miss
Macro-region: Europe
Country: United Kingdom
Date: 23/07/2013
Main component involved?: Valve (Generic)
How was it involved?: Malfunctioning
Initiating cause: Conventional Component Failure (Compressed Air)
Root causes: Material/ Manufacturing Error
Root CAUSE analysis: It was found that a snap connector on an air line in the fuel cell workshop had come apart overnight. The air supply was restored and fuelling took place normally so that no buses were delayed for service. Before the workshop was locked up there was no indication that the near miss would occur. Investigation found that the connector was fitted with the correct crimp.

Application: Hydrogen Refuelling Station
Sub-application: Hydrogen dispenser
Hydrogen supply chain stage: Hydrogen Delivery (No additional details provided)
All components affected: H2 dispenser
Location type: Open
Operational condition: Abnormal
Pre-event occurrences: The refuelling station was working on only one dispenser, because the other one had been shut down for repairing a leakage.

Number of injured persons: 0
Number of fatalities: 0
Post-event summary: The air supply was restored and fuelling took place normally so that no buses were delayed for service.

Corrective Measures: It has been ensured that the taps to the air lines are closed before the workshop is shutdown, removing in this way risk of a similar incident or near miss happening again. The Producer will check their nitrogen supply to ensure that it keeps the correct pressure in the system also in the event of a compressed air failure.