Fig.1. Classification of self-rescuer to population

As parameter of efficiency of use of the self-rescuer the probability of maintenance of protection of the person can serve in extreme situation Рз (t), counted under the formula:

РЗ(t) = РН* РО(t), (1)

where: РН - Probability of presence of the self-rescuer at the person during the moment of occurrence of an extreme situation

РО(t) - Probability of non-failure operation of the self-rescuer during time t.