Pyrophoric Liquids

PYROPHORIC GASES AND LIQUIDS

DOE-HDBK-1081-94

Spontaneous Heating and Pyrophoricity

Pyrophoric Liquids

Hydrazine

Properties

Hydrazine is a colorless oily liquid resembling water in appearance and

possesses a weak, ammonia-like odor. Its chemical formula is N2 H4 .

Commercially it is available as an anhydrous (without water) liquid and in

aqueous solutions. Hydrazine is most well known for its use as a rocket fuel,

but is also used in manufacturing agricultural chemicals, explosives, and

plastics. It fumes in air and reacts with all oxidizing agents. Hydrazine is

hypergolic, meaning that it reacts explosively upon contact with many

oxidizing agents. The flash point of hydrazine is 38 C (100 F). Its

autoignition temperature is 270 C (518 F) on a glass surface but may be as

low as 23 C (74 F) when in contact with a strong oxidizing agent. Hydrazine

forms flammable mixtures with air from 4% to 100% by volume and

decomposes when heated. Hydrazine ignites in air at room temperature when

exposed to metal oxide surfaces and in a wide variety of porous materials.

Storage and Handling

Storage in a detached building is preferred. Inside storage should be in a

standard flammable liquids storage warehouse, room, or cabinet. An

emergency water reservoir or sprinklers should be provided for fire

extinguishment. Hydrazine should be stored separately from metal oxides,

acids, and all oxidizing agents. Hydrazine is highly toxic and may be fatal if

inhaled or absorbed through the skin. It is also corrosive and may cause severe

eye and skin burns. Protective clothing that prevents penetration of hydrazine

and positive pressure self-contained breathing apparatus must be worn when

working with hydrazine.

Extinguishing Hydrazine Fires

Fires involving hydrazine may produce irritants and toxic gases such as

nitrogen oxides. Fires should not be approached without protective clothing

and positive pressure respirators. Hydrazine fires should be approached from

upwind to avoid hazardous vapors and toxic decomposition products.

Flooding amounts of water should be applied as a fog or spray. Water should

be sprayed on fire-exposed containers of hydrazine to keep them cool. Fires

should be fought from a protected location or at a maximum possible distance.

Flooding amounts of water may be necessary to prevent reignition.

Pyrophoricity

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