Introduction to Hazardous Evaluation Techniques Guidelines for Hazardous Evaluation Procedures (1992 by AIChE). Second Edition with Worked Examples. Center for Chemical Process Safety (CCPS). American Institute of Chemical Engineers (AIChE).

Hazard Evaluation Techniques

HAZOP HAZOP was developed by Lawley (1974) of ICI. Based on early account by Elliott & Owen (1968). Hazop studies are carried out by an experienced, multidisciplanary team. Review all physical aspects of a process (lines, equipment, instrumentation) to discover potential hazards.

Basis for HAZOP The basis for a HAZOP is a critical examination of information found in a word model. It includes a flowsheet, a plant layout, equipment specification or a P&ID, (Piping and Instrument Drawing).

Hazop Includes

Hazop Guide Words

Common HAZOP Analysis Process Parameters

Prepare for the Review

Hazop Flow Sheet

Hazop Pitfalls

Other Pitfalls Inexperienced HAZOP team. Inadequately trained or in-experienced leader.

Common Hazop Mistakes Failing to establish a "safe" environment for team members. Consequences of events not carried to conclusion. Taking unwarranted credit for safeguards. Too little credit given for safeguards.

Hazop Mistakes Cont’d Failure to make recommendations as specific as possible. Poor record keeping of HAZOPS. Failure to HAZOP start-up and shut- down procedures. P&IDs not up-dated or poorly constructed.

Hazop Mistakes Cont’d A HAZOP is performed in lieu of properly executed design reviews. Wrong technique for system being reviewed (See spreadsheet titled Fig 5.3).

HAZOP Example

Standard Set of Deviations

Typical Hazop Worksheet

Check List Example

Check List Cont’d

End of HAZOP Presentation. Presented to ES-317y 27 Feb, 2001 By R.A. Hawrelak