Hydrogen safety

Hydrogen safety

Hydrogen safety covers the safe use and handling of hydrogen. Hydrogen poses unique challenges due to its ease of leaking, low-energy ignition, wide range of combustible fuel-air mixtures, buoyancy, and its ability to embrittle metals that must be accounted for to ensure safe operation. Liquid hydrogen poses additional challenges due to its increased density and extremely low temperatures.

Hydrogen codes and standards

Hydrogen codes and standards are codes and standards (RCS) for hydrogen fuel cell vehicles, stationary fuel cell applications and portable fuel cell applications.

Additional to the codes and standards for hydrogen technology products, there are codes and standards for hydrogen safety, for the safe handling of hydrogen and the storage of hydrogen.
*Standard for the installation of stationary fuel cell power systems (National Fire Protection Association)


The current ANSI/AIAA standard for hydrogen safety guidelines is AIAA G-095-2004, Guide to Safety of Hydrogen and Hydrogen Systems [cite web
url= http://aero-defense.ihs.com/document/abstract/GFEIHBAAAAAAAAAA
title= AIAA G-095-2004, Guide to Safety of Hydrogen and Hydrogen Systems
format= PDF
publisher= AIAA
accessdate = 2008-07-28
] . As NASA has been one of the world's largest users of hydrogen, this evolved from NASA's earlier guidelines, NSS 1740.16 (8719.16). [cite web
url= http://www.hq.nasa.gov/office/codeq/doctree/canceled/871916.pdf
title= Safety Standard for Hydrogen and Hydrogen Systems
last= Gregory | first= Frederick D.
date= Feb. 12, 1997 | format= PDF |work= |publisher= NASA
accessdate= 2008-05-09
] These documents cover both the risks posed by hydrogen in its different forms and how to ameliorate them.


* "Hydrogen-air mixtures can ignite with very low energy input, 1/10th that required igniting a gasoline-air mixture. For reference, an invisible spark or a static spark from a person can cause ignition."
* "Although the autoignition temperature of hydrogen is higher than those for most hydrocarbons, hydrogen's lower ignition energy makes the ignition of hydrogen–air mixtures more likely. The minimum energy for spark ignition at atmospheric pressure is about 0.02 millijoules."


* "The flammability limits based on the volume percent of hydrogen in air (at 14.7 psia) are 4.0 and 75.0. The flammability limits based on the volume percent of hydrogen in oxygen (at 14.7 psia) are 4.0 and 94.0."
* "Explosive limits of hydrogen in air are 18.3 to 59 percent by volume"
* "Flames in and around a collection of pipes or structures can create turbulence that causes a deflagration to evolve into a detonation, even in the absence of gross confinement."

(For comparison: Deflagration limit of gasoline in air: 1.4–7.6%)


* "Leakage, diffusion, and buoyancy: These hazards result from the difficulty in containing hydrogen. Hydrogen diffuses extensively, and when a liquid spill or large gas release occurs, a combustible mixture can form over a considerable distance from the spill location."
* "Hydrogen, in both the liquid and gaseous states, is particularly subject to leakage because of its low viscosity and low molecular weight (leakage is inversely proportional to viscosity). Because of its low viscosity alone, the leakage rate of liquid hydrogen is roughly 100 times that of JP-4 fuel, 50 times that of water, and 10 times that of liquid nitrogen."

Liquid hydrogen

* "Condensed and solidified atmospheric air, or trace air accumulated in manufacturing, contaminates liquid hydrogen, thereby forming an unstable mixture. This mixture may detonate with effects similar to those produced by trinitrotoluene (TNT) and other highly explosive materials"

Liquid Hydrogen requires complex storage technology such as the special thermally insulated containers and requires special handling common to all cryogenic substances. This is similar to, but more severe than liquid oxygen. Even with thermally insulated containers it is difficult to keep such a low temperature, and the hydrogen will gradually leak away. (Typically it will evaporate at a rate of 1% per day. [http://www.almc.army.mil/alog/issues/MayJun00/MS492.htm] )


Hydrogen collects under roofs and overhangs, where it forms an explosion hazard; any building that contains a potential source of hydrogen should have good ventillation, strong ignition suppression systems for all electric devices, and preferably be designed to have a roof that can be safely blown away from the rest of the structure in an explosion. It also enters pipes and can follow them to their destinations. Hydrogen pipes should be located above other pipes to prevent this occurrence. Hydrogen microsensors allow for rapid detection of hydrogen leaks to ensure that the hydrogen can be vented and the source of the leak tracked down. As in natural gas, an odorant can be added to hydrogen sources to enable leaks to be detected by smell. While hydrogen flames can be hard to see with the naked eye, they show up readily on UV/IR flame detectors.


Hydrogen has been feared in the popular press as a relatively more dangerous fuel, and hydrogen in fact has the widest explosive/ignition mix range with air of all the gases except acetylene. However this can be mitigated by the fact that hydrogen rapidly rises and disperses before ignition. Unless the escape is in an enclosed, unventilated area, it is unlikely to be serious. Hydrogen also usually rapidly escapes after containment breach. Additionally, hydrogen flames are difficult to see, so may be difficult to fight. An experiment performed at the University of Miami attempted to counter this by showing that hydrogen escapes while gasoline remains by setting alight hydrogen- and petrol-fuelled vehicles. [ cite web
url= http://www.evworld.com/article.cfm?storyid=482
title= Hydrogen Car Fire Surprise
date= January 18, 2003 |work= |publisher=
accessdate= 2008-05-09

In the LZ 129 Hindenburg disaster, 2/3 of passengers and crew survived. The skin of the Hindenburg may have contributed to the actual blaze. Of the 62 passengers, 27 died. Of the 27 dead, 25 jumped to their deaths from the stricken airship in panic. The other 2 that died did so due to the fire spreading to the diesel powered engines. The hydrogen combustion itself was above, and mostly away from the gondola.

In a more recent event, an explosion of compressed hydrogen during delivery at the AEP Muskingum River Coal Plant caused significant damage and killed one person. [ cite web
url= http://www.washingtonpost.com/wp-dyn/content/article/2007/01/08/AR2007010800350.html
title= "Ohio Power Plant Blast Kills 1, Hurts 9"
last= Williams | first= Mark
date= January 8, 2007 |work= | publisher= Associated Press
accessdate= 2008-05-09
] [ cite web
url= http://www.eei.org/meetings/nonav_2007-04-29-cs/Citations_Accident_Review.pdf
title= Muskingum River Plant Hydrogen Explosion January 8, 2007
date= November 11, 2006 | format= PDF |publisher= American Electric Power
accessdate= 2008-05-09

ee Also

*Hydrogen embrittlement
*Hydrogen economy
*Compressed hydrogen
*Liquid hydrogen
*Slush hydrogen
*Metallic hydrogen


External links

* [http://www.hysafe.org/ Hysafe]
* [http://www.hydrogenandfuelcellsafety.info Hydrogen and fuelcell safety]
* [http://www.ehammertraining.us/energy/h2_login/login.cfm DOE-Hydrogen safety for First Responders]
* [http://hazmat.dot.gov/pubs/erg/erg2008_eng.pdf First Responders - Emergency Response Guidebook - Guide 115]

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Hydrogen leak testing — is the normal way in which a hydrogen pressure vessel or installation is checked for leaks or flaws. There are various tests.*The Hydrostatic test, The vessel is filled with a nearly incompressible liquid usually water or oil and examined for… …   Wikipedia

  • Hydrogen codes and standards — are codes and standards (RCS) for hydrogen fuel cell vehicles, stationary fuel cell applications and portable fuel cell applications.Codes and standards have repeatedly been identified as a major institutional barrier to deploying hydrogen… …   Wikipedia

  • Hydrogen embrittlement — (or hydrogen grooving) is the process by which various metals, most importantly high strength steel, become brittle and crack following exposure to hydrogen. Hydrogen cracking can pose an engineering problem especially in the context of a… …   Wikipedia

  • Hydrogen economy — The hydrogen economy is a proposed system of delivering energy using hydrogen. The term hydrogen economy was coined by John Bockris during a talk he gave in 1970 at General Motors (GM) Technical Center.[1] Hydrogen advocates promote hydrogen as… …   Wikipedia

  • Hydrogen — This article is about the chemistry of hydrogen. For the physics of atomic hydrogen, see Hydrogen atom. For other meanings, see Hydrogen (disambiguation). ← hydrogen → helium …   Wikipedia

  • Hydrogen vehicle — A hydrogen vehicle is a vehicle that uses hydrogen as its on board fuel for motive power. The term may refer to a personal transportation vehicle, such as an automobile, or any other vehicle that uses hydrogen in a similar fashion, such as an… …   Wikipedia

  • Hydrogen peroxide — IUPAC name …   Wikipedia

  • Hydrogen sulfide — Systematic name …   Wikipedia

  • Hydrogen production — Hydrogen is commonly produced by extraction from hydrocarbon fossil fuels via a chemical path. Hydrogen may also be extracted from water via biological production in an algae bioreactor, or using electricity (by electrolysis), chemicals (by… …   Wikipedia

  • Hydrogen storage — describes the methodologies for storing H2 for subsequent use. The methodologies span many approaches, including high pressures and cryogenics, but usually focus on chemical compounds that reversibly release H2 upon heating. Hydrogen storage is a …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.