Basics
Hydrogen has a long history of safe use in the chemical and aerospace industries. An understanding of hydrogen properties, proper safety precautions and engineering controls, and established rules, regulations and standards are the keys to this successful track record.
As the use of hydrogen and fuel cell systems expand, codes and standards will be needed to provide the information to safely build, maintain, and operate hydrogen and fuel cell systems and facilities, to ensure uniformity of safety requirements, and to assure local code officials and safety inspectors that sufficient safety standards have been met.
What are Codes & Standards?
Codes and standards are needed to ensure the safety of hydrogen and fuel cell systems and to facilitate the commercialization of hydrogen as a fuel. Building codes and equipment standards provide a systematic and accurate means of measuring and communicating product risk and insurability to the customer, general public, and fire-safety certification officials.
"Codes" are established by jurisdictions—for example, building codes, fire codes, building ordinances, etc. Today, there are over 44,000 jurisdictions in the United States and some of these existing jurisdictional codes could affect hydrogen use. "Standards" are agreed upon to ensure consistency, compatibility, and safety. Many organizations are cooperating in the development of codes and standards to ensure safety and encourage the safe commercialization of hydrogen uses.
For more basic information about safety, codes and standards, see:
- Hydrogen Safety Basics
- Safety Systems Animation of a Hydrogen-Fueled Vehicle
- Animation of Hydrogen Fueling Station Layout
Comparison of Hydrogen to Conventional Fuels
With proper handling and controls, hydrogen can be as safe as, or safer than, other fuels we use today. Safety considerations associated with handling hydrogen include fire, explosion, and asphyxiation. Below is a chart that shows how hydrogen stacks up against some common fuels.
| Properties of Hydrogen, Natural Gas, Gasoline, and Propane | ||||
|---|---|---|---|---|
| Hydrogen (gas) |
Natural Gas (gas) |
Gasoline (liquid) |
Propane (liquid) | |
| Lower heating value (BTU/lb) | 51,532 | 21,300 | 18,000 - 19,000 | 19,800 |
| Density at standard conditions (pounds per gallon) | 0.0007a | 0.005a | 6.0-6.5a | 4.22 |
| Autoignition temperature in air (°F) | 1,050 - 1,080 | 1,004 | 495 | 850 - 950 |
| Volume concentrations for flammability in air (%) | 4.1 - 74 | 5.3 - 15 | 1.4 - 7.6 | 2.2 - 9.5 |
| Diffusion coefficient in air (inches squared/second) | 0.0946b | 0.0248b | 0.008b | 0.017c |
| Toxicity to humans | Non-toxic, simple asphyxiant | Non-toxic, simple asphyxiant | Poisonous, irritant to lungs, stomach and skin | Non-toxic, simple asphyxiant |
Sources: All values are from DOE Alternative Fuels Data Center, except as follows:
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