Safety Considerations Associated with Handling Liquid Hydrogen

The hazards associated with handling liquid hydrogen are fire, explosion, and exposure to freeze burn. In addition, the minimum ignition energy for flammable mixtures containing hydrogen is extremely low. Burns may result from unknowingly walking into a hydrogen fire. These fire and explosion hazards can be controlled by appropriate design and operating procedures.

In addition, even though hydrogen gas is odorless and nontoxic, it may produce suffocation by diluting the concentration of oxygen in the air below levels necessary to support life.

Preventing the formation of combustible fuel-oxidant mixtures and removing potential sources of ignition (electric spark, static electricity, open flames, and so forth) in areas where the hydrogen will be used is essential. Careful evacuation and purge operations should be used to prevent the formation of flammable or explosive mixtures.

Adequate ventilation helps to reduce the possible formation of flammable mixtures in the event of a hydrogen leak or spill and will also eliminate the potential hazard of asphyxiation. Workers should always wear protective clothing to prevent exposure to extremely cold liquid and cold hydrogen vapors.

Cold burns may occur from short contact with frosted lines, liquid air that may be dripping from cold lines or vent stacks, vaporizer fins, and vapor leaks. Air condenses at the same temperature as liquid hydrogen and can become an oxygen-enriched liquid due to the vaporization of nitrogen. Oxygen-enriched air also increases the combustion rate of flammable and combustible materials.

To learn more about Hydrogen Fuel Cell Safety visit our Hydrogen Fuel Cell Safety Online Training web page.