Hydrogen has a high lower flammability limit and a high flammability temperature (4% and 580 °C, respectively), but is flammable over a wide range. It is easily ignited on ignition.
There is little chance of ignition in an open space due to the rapid dissipation of hydrogen due to its low density.
Does not form fuel "puddles".
Does not float on the surface of the extinguishing agent.
Hydrogen burns at high temperatures but very quickly. If there is no combustible material nearby, the fire will quickly go out.
Hydrogen flames are difficult to extinguish and can spread quickly.
Hydrogen flame emits little heat and is less likely to cause burns.
