Event
- Event ID
- 325
- Quality
- Description
- An explosion occurred in a Dewar used for metals tensile testing at liquefied hydrogen temperatures. The container consisted of vacuum insulated bottom and of cylindrical shaped polyurethane foam top. The venting of hydrogen was through a 2 inch diameter hole in the side of the foam insulation. The boil-off of liquid hydrogen was being accelerated by the use of two electric heaters on the bottom of the Dewar. Explosion was evaluated equivalent to about 0.25 lb TNT. This was followed by the dispersion of hydrogen which resulted in further hydrogen-air explosions.
[Ordin, NASA (1974)] - Event Initiating system
- Classification of the physical effects
- Hydrogen Release and Ignition
- Nature of the consequences
- Macro-region
- North America
- Country
- United States
- Date
- -
- Main component involved?
- Cryogenic Vessel
- How was it involved?
- Internal Explosion (H2-Air Mixture)
- Root causes
- Root CAUSE analysis
- The INITATING CAUSE was the formation of a air-hydrogen mixture inside the Dewar.
Air is believed to have backed into it through the vent hole in the polyurethane top. It was possible that air could have been cryo-pumped into it due to the high porosity of the foam.
Ignition is believed to be caused by high surface temperature of heaters.
The ROOT CAUSE was inadequate design of the system.
Facility
- Application
- Laboratory / R&d
- Sub-application
- Aerospace
- Hydrogen supply chain stage
- All components affected
- dewar
- Location type
- Unknown
- Operational condition
Emergency & Consequences
- Number of injured persons
- 0
- Number of fatalities
- 0
- Environmental damage
- 0
Event Nature
- Release type
- liquid
- Involved substances (% vol)
- H2 100%
- Presumed ignition source
- Hot surface
References
- Reference & weblink
Mishap no 35 in <br />
P. L. Ordin, Review of hydrogen accidents and incidents in NASA operations, 1974, NASA TM X-71565<br />
https://ntrs.nasa.gov/citations/19740020344Lowesmith et al., Safety issues of the liquefaction, storage and transportation of liquid hydrogen: An analysis of incidents and HAZIDS, Int. J. Hydrogen energy (2014) https://doi.org/10.1016/j.ijhydene.2014.08.002
Hankinson and Lowesmith, Qualitative Risk Assessment of Hydrogen Liquefaction, Storage and Transportation, FCH JU project IDEALHY, Deliverable 3.10 (2013)<br />
confidential<br />
(accessed October 2025)Hankinson and Lowesmith, HAZIDs for Hydrogen Liquefaction, Storage and Transportation , FCH JU project IDEALHY, Deliverable 3.11 (2013)<br />
https://www.idealhy.eu/uploads/documents/IDEALHY_D3-10%20HAZIDs_Liquefa… />
(Only summary publicly available, accessed October 2025)
JRC assessment
- Sources categories
- ORDIN
