Is hygrogen safe?

Abstract

The safety aspects of hydrogen are systematically examined and compared with those of methane and gasoline. Physical and chemical property data for all three fuels are compiled and used to provide a basis for comparing the various safety features of the three fuels.Each fuel is examined to evaluate its fire hazard, fire damage, explosive hazard and explosive damage characteristics. The fire characteristics of hydrogen, methane and gasoline, while different, do not largely favor the preferred use of any one of the three fuels; however, the threat of fuelair explosions in confined spaces is greatest for hydrogen.Gasoline is believed to be the easiest and perhaps the safest fuel to store because of its lower volatility and narrower flammable and detonable limits.It is concluded that all three fuels can be safely stored and used; however, the level of safety risk for each fuel will vary from one application to another. Generalized safety comparisons are made herein but detailed safety analyses will be required to establish the relative safety of different fuels for each specific fuel application and stipulated accident. The technical data supplied in this paper will provide much of the framework for such analyses. Hydrogen safety guidelines, regulatory codes applicable to the distribution of hydrogen, and safety criteria for liquid hydrogen storage are compiled and presented.

Hydrogen Fuel Tank Fire Exposure Burst Test

“…Hord [5] has reported the following simple empirical equation for predicting the hydrogen fireball diameter D f , based on tests with rocket propellants.…”

Hydrogen Blending into Natural Gas Pipeline Infrastructure: Review of the State of Technology

“…Hydrogen admixtures also become more unstable with higher hydrogen contents, as hydrogen has a wider window of flammability and lower minimum ignition energy (Mathurkar 2009). Pure hydrogen gas flames are difficult to detect, as they are nearly invisible during daylight (Hord 1976;HySafe 2007). Flame visibility improves with the presence of impurities such as methane.…”

“…The latter effect on temperature has implications in emissions as more nitrogen oxides (NO x ) could be formed. Gas explosivity limits are case-dependent and depend on additional conditions such as ignition location, ignition strength, and confinement (Hord 1976). These limits require a more detailed analysis than the high-level overview presented in Table 4.…”