The paper presents the most important notions and definitions used in
research concerning the gaseous mixtures explosivity, bringing them up
to the most recent international standards. The explosions initiated
by local energy sources are dealt with separately from the self igniti
ons. For each of them, the most usual parameters characterizing the ex
plosive regime installation: and propagation, the standard or non stan
dard methods of measure, the factors influencing the respective parame
ters value, As well as the possible correlations between them, are spe
cified.