Before revision: Types The original Swedish terminology related to the term 'flashover' has been altered in its translation to conform with current European and North American accepted scientific definitions as follows: A lean flashover (sometimes called rollover) is the ignition of the gas layer under the ceiling, leading to total involvement of the compartment.
After revision: Types  A lean flashover (sometimes called rollover) is the ignition of the gas layer under the ceiling, leading to total involvement of the compartment.