A Hazard & Operability Study (HAZOP) is a systematic and highly structured study with a critical approach to examine the process and engineering intentions of the process design.

HAZOP analysis is mainly carried out during the basic project phase to have enough time to implement the recommendations during the project. HAZOP can also be carried out for plants during the operational phase, but this is unusual because it is not expected to be implemented or to perform modifications in the plant during this phase. However, it is very important to carry out HAZOP analysis during the operational phase whenever a specific modification process is implemented. In this case it is also necessary to take into account the impact of such modification on other subsystems and to consider them in HAZOP.

Hazard and Operability Study (HAZOP) helps identify and evaluate problems that may represent risks to personnel, equipment or project efficiency. Multi-disciplinary teams focus on specific nodes of the project design during a series of workshops. For each node, the team examines the guide words to methodically ensure that the process is explored in every possible way.

The key objectives of a HAZOP study are to:

• Identify safety related hazards and operability problems that could directly threaten the safety of the facilities, personnel or cause operational problems;
• Determine the consequences for the identified hazards and operability issues;
• Identify engineering and procedural safeguards already incorporated into the design;
• Evaluate the adequacy of existing engineering and procedural safeguards; and
• Offer recommendations to eliminate or mitigate the identified problems, and to identify areas that need to be investigated further.