The method
The team divides the system or task into parts and, for each part, generates questions of the form “what if…?”: what if the feed fails, what if the valve is left open, what if the wrong substance is connected, what if the operator does not hand over the information at shift change. For each question three things are written: consequence, existing safeguard, recommendation.
How it differs from HAZOP
| What-if | HAZOP | |
|---|---|---|
| Question generation | Free, based on the team's experience | Systematic, using guide words |
| Duration | Short | Long |
| Completeness | Depends on the team | Depends on the method |
When it is preferred
- where the process is simple or well understood,
- where a change needs a fast assessment,
- as a screening pass before committing to a full HAZOP,
- for non-process work: maintenance, transport, storage, field operations.
Its weakness, and the remedy
Nothing in the structure guarantees completeness; a team does not ask the question it did not think of. In practice it is therefore run with a checklist: the list reminds, the team goes deeper. Together they outperform either on its own.
How it is recorded
Questions and answers are written out in full — including questions asked and dismissed, because the next assessment needs to know whether that question was asked. Recommendations get owners and dates.