Fire in an aerospace company

A fire was sparked by a hydrogen leak at a company producing composites for aircraft parts.
The fire started in a pipe bringing hydrogen from a storage tank to the oven.
The fire was a two-inch jet flame (50 mm) from a pinhole leak facility. The incident occurred during normal operations, but hydrogen was not in use by any process in the facility at the time.
The flame was discovered by a contractor who was about to start welding on scaffolding about 3-5 feet away (1 to 1.5 m). Before starting, as prescribed by the procedure, the welder searched the immediate area for any signs of fire. The plant supervisor was informed.

A first attempt to extinguish the fire by means of a fire extinguisher obtained only the result of enlarging the flame. The area was evacuated, and the local fire department was informed. The operators began to shut down the five furnaces that were online.

The local fire department stopped the traffic on the access street and closed the hydrogen valves connected to the hydrogen storage tank.
There were nearby gas feed shelter containing hazardous chemicals and other flammable gas lines. The likelihood that the fire reached the shelter was assessed as highly unlikely, therefore, the firefighters decided to allow the fire to burn out.

Since after 30 minutes the fire was still burning, the hydrogen supplier was contacted, who explained that the distance between the tank to the fire location was 100 feet (30 m) and therefore advised that it might require an extended length of time for the pressure in the line to drop enough for the fire to go out and dispatched a technician to the site to check that the hydrogen storage tank had been properly isolated.
An operator and a firefighter, both wearing PPE and breathing gear, went back into the area of the fire to check if all equipment was properly turned off. They verified that the fire had burned out.

The INITIATING CAUSE was the ignited release of hydrogen from a hole in a hydrogen line.

The ROOT CAUSE is unknown.

pipe, tank,oven

DESCRIPTION OF THE PLANT
The plant manufactured composites used in the aircraft industry by creating different chemicals using high-temperature ovens with very special atmospheres. Very probably hydrogen was used to create a reduction tmosphere in the ovens.

Probably none

The plant did the following:
• Replaced the existing copper and carbon steel hydrogen pipeline with ¾-inch schedule 40 stainless steel.
• Rerouted the new hydrogen line in the preferred location.
• Located new hydrogen shut-off valves in a more convenient location.
• Removed all abandoned underground hydrogen lines.
• Regularly interacted with the local fire department on the new piping system design until the project is completed.