Definition:
A Hazard and Operability Study (HAZOP) systematically examines potential deviations from design intent to identify hazards and operability issues. This is done per the excellent IEC 61882. There are often special software packages along with specially trained HAZOP leaders. Although a software package is sometimes used, a HAZOP can and is often done in a large spreadsheet. It is generally a meeting with many stakeholders and multiple days. It can be painful, especially if the right people are not present or people are unprepared.
HAZOPs can at times be done in stages. Such as a first stage after detailed design once the PIDs are developed to a certain extent. Then another stage once the specific equipment is chosen. It just depends on many factors applicable to the team and process.
Often a HAZOP is combined with a LOPA. They naturally fit together in how they are structured. In this case, it is an even bigger meeting and a more complicated tool.
Key Points:
- Uses guide words like “high,” “low,” “none,” “reverse.”
- Forms basis for many SIF and IPL requirements.
- Often a multi-day meeting with various stakeholders.
- Often combined with the LOPA, into one even longer meeting!
- A method to do the H&RA as required by IEC 61511-1.
Example:
A HAZOP team finds that blocked flow in a cooling water line could cause reactor overheating.
See Also: H&RA, HAZID, LOPA, process hazard analysis (PHA)
Cited Source:
- IEC 61882:2016
- University of Michigan Chemical Engineering – HAZOP
- Sphera – What is the Difference Between PHA, HAZOP, & LOPA