A facility replaced the copper tubing used for hydrogen distribution, with stainless steel tubing. This was done to address a fire protection concern related to the solder on the copper tubing being susceptible to heat, melting, and releasing a flammable gas. The facility maintenance personnel completed the replacement, noted the pressure on the hydrogen bottle, and left the building. When the maintenance person returned on the following day, s/he noticed the pressure on the hydrogen bottle had dropped 500 psi overnight, indicating a leak in the system. S/he notified the appropriate facility personnel and together they began to determine why the hydrogen had dropped 500 psi overnight. The hydrogen line originates at a manifold, which is part of a glove box atmosphere purification view more
A pinhole at the base of a hand-held hydrogen torch, allowed hydrogen to leak. In the process of lighting a second torch, the leaking hydrogen was ignited. The operator, being startled by the "pop" of the lighted hydrogen allowed the #2 torch to drop and hang by its hose support approximately 6" from the floor. The hydrogen and oxygen hoses on the #1 torch were burned through and hung approximately 12" from the floor. The free burning #1 hose burned the #2 hydrogen and oxygen hose assembly through, causing both hoses assemblies to burn without valve control. The hose size is 1/4" and is used in various areas of the plant.
An apprentice mechanic lacerated his right forearm while quickly sliding out from under a hydrogen prototype bus when the bus slipped off a hydraulic jack. The apprentice and another mechanic had raised the bus about 1 foot from the ground to position it on jack stands when the hydraulic jack tipped over. The apprentice went to the site medical facility, where he needed five stitches to close the wound in his forearm.
The mechanics were raising the rear of a hydrogen prototype bus, like the one in the figure below, and placing it on jack stands. After chocking the wheels, they used bottle jacks on each side of the rear axle to raise the bus high enough to place a 20-ton hydraulic jack under the differential. With the bus resting on a pair of small jack stands, they raised the view more
A 2000-psia-rated gas cylinder (nominal size 10"x1 1/2") was being filled with hydrogen to a target pressure of 1500 psia. The cylinder suffered a failure at an indicated pressure of 1500 psia during filling. Investigation of the failure subsequently revealed that a faulty digital readout had allowed the cylinder to be over-pressurized. There were no safety consequences due to the failure and no damage to the facility or equipment. The cylinder was being filled in a test vault that was specially designed for the high-pressure burst testing of pressure vessels and components. While no over-pressure cylinders were released from the laboratory for use, this incident is being reported to address the potential and subsequent lessons learned.
Investigations revealed that the view more
An employee noticed an unusual smell in a fuel cell laboratory. A shunt inside experimental equipment overheated and caused insulation on conductors to burn. Flames were approximately one inch high and very localized. The employee de-energized equipment and blew out the flames. No combustible material was in the vicinity of the experiment. The fire was contained within the fuel cell and resulted in no damage to equipment.
The employee was conducting work with a fuel cell supplied by oxygen gas. The hazard control plan (HCP) associated with the work was for use with fuel cells supplied by air or hydrogen, but not for oxygen, which yields a higher current density. The technician had set up the station wiring to handle a current of 100 amps and the shunt was configured to handle a view more
Installation of a 9000-gallon liquid hydrogen storage tank by a lessee at a building has not been evaluated for effect on the Safety Authorization Basis (SAB) of nearby facilities.
During review of an Emergency Management Hazard Assessment document, a reviewer questioned whether the SAB of nearby facilities had been reviewed for the effect of the installed 9000-gallon liquid hydrogen tank. Reviews by the facility management and facility safety personnel confirmed the evaluations have not been performed.
The direct cause was determined to be a management problem, with policy not adequately defined, disseminated, or enforced to integrate potential lessee hazards into the facility safety program documentation on the 9000-gallon hydrogen tank and delivery. The existing policy view more
A hydrogen gas detector on the ground floor of a building registered the release of a small amount of hydrogen gas and actuated automatic alarms both at the fire department and in one of its buildings. Additionally, interlocks connected to the gas detector completely shut down the experiment. Upon hearing the alarm, all occupants (about 6) promptly left the building. Fire department personnel are housed in the trailer next to a building and responded within one minute. They tested the atmosphere within the building, reset the gas detector, and secured the alarm at 9:15. The alarm was actuated when an experimenter assigned to the experiment was evacuating lines using a vacuum pump.
The speed of evacuation was controlled by a commercially manufactured flow meter. It is believed view more
While refilling the hydrogen system after an outage caused by a power failure, the excess flow valve located at the hydrogen tank tripped, but did not go fully shut.
The large valve is equipped with a small bypass valve so that the valve can be pressurized on both sides as is required before the valve can be reset. The O-ring which makes this small valve gas tight was deformed and improperly seated, thus allowing gas to flow to each side of the large valve. This permitted the valve to trip normally, but not to seat properly. The following is the manufacturer's evaluation after disassembly and inspection of the valve.
This valve was recently installed to provide excess flow protection to the underground portion of the hydrogen system piping and to provide redundant view more
While attempting to light the hydrogen flare inside a Metalorganic Chemical Vapor Deposition (MOCVD) system burn box, a small explosion occurred, blowing the back section of the burn box off. Hydrogen flow was shut down immediately, and this MOCVD operation was suspended. Researchers made the determination that this was a minor incident and there were no injuries.
The follow-up investigation determined that the MOCVD HEPA filter had become sufficiently loaded to the point where performance of the burn box exhaust ventilation system was significantly degraded. The static pressure created across the "loaded" HEPA filter equaled the operating static pressure of the exhaust ventilation system servicing the burn box. This resulted in a region of "dead air" in the view more
While filling a sample cylinder with compressed hydrogen gas, a quick-disconnect coupler fitting came loose within a stainless steel laboratory hood, allowing a small purge of the hydrogen gas to escape directly into the hood through ~1/4-inch Tygon tubing. The stainless steel quick-disconnect fitting struck the stainless steel bottom of the laboratory hood and the hydrogen gas caught fire. It is not known what caused the hydrogen gas to catch fire. The most likely sources of a spark was from metal-to-metal contact of the quick-disconnect fitting with the laboratory hood floor, or the discharge of static electrical charge generated by flow of hydrogen gas through Tygon tubing. The resultant narrow jet of fire, directed toward the left side of the laboratory hood, extinguished itself view more