HAZOP study is a review of the Piping & Instrumentation Diagram (P&IDs) of the system /
plant and ensures that adequate protection is provided by way of instrumentation, interlocks
& others to mitigate any operational hazard that may get generated by any process upset
A HAZOP analysis comprises of a structured technique in which a multi-discipline team
performs a systematic study of a process using guide words to discover how deviations from
the design intent can occur in equipment, actions, or materials, and whether the consequences
of these deviations can result in a hazard.
The results of the HAZOP analysis are the team's recommendations, which include
identification of hazards and the recommendations for changes in design, procedures, etc. to
improve the safety of the system. Deviations during normal, startup, shutdown, and
maintenance operations are discussed by the team, and improvements thereon are included in
the study report.
The following terms are used in the HAZOP process:
- Design Intent - the way a process is intended to function.
- Deviation - a departure from the design intent discovered by systematically applying guide
words to process parameters.
- Guide Word - simple words such as "high" pressure, "high" temperature, "leak" etc. that are
used to modify the design intent and to guide and stimulate the brainstorming process for
identifying process hazards.
- Cause - the reason why a deviation might occur.
- Consequence - the results of a deviation.
- Safeguard - engineered systems or administrative controls that prevent the causes or
mitigate the consequences of deviations.
- Hazard Category - an assessment of the hazard risk of the operation.
- Recommendations - recommendations for design changes, procedural changes, or for
Section wise HAZOP Study is carried out in two Phases. Initial HAZOP study is done with
first issue of P&I drawings. Final HAZOP study is done when P&I drawings have been
finalized with information from different equipment vendors.