In simple term, hazard analysis means classification of hazards, eg. chemical hazards, mechanical
hazards, electrical hazards, fall hazards, day and night wise hazards etc. in this way it is qualitative
analysis.
Hazard Analysis is (i) Analysis of mechanism of hazard occurrence and (ii) Analysis of terminal
consequences of hazards which may include number of injury, fatality, property damage and other loses.
In this way it is quantitative analysis. Its study is known as HAZAN (Hazard Analysis). It means
identification of undesired events, which lead to the materialization of a hazard, analysis of the
mechanism by which such .undesired events could occur, and estimation of the extent, magnitude and
likelihood of any harmful effects or consequences.
Preliminary Hazard Analysis (PHA) is a procedure for identifying hazards early in the design
phase of project before the final design has been established. Its purpose is to identify opportunities for
design modifications, which would reduce or eliminate hazards, mitigate the consequences of accidents
or both.
HAZAN (Hazard analysis) is generally undertaken at the preliminary stage of determining the
location, basic design principles and operational parameters to establish the adequacy of basic safety of
design, operation and environmental control. It may be followed by an updated analysis to establish final
risk levels. HAZAN exercise has to be undertaken by a professional team with expertise in failure mode
and effect analysis, fault tree analysis, simulation and modelling, event tree and consequence analyses.