HAZOP
Hazard and Operability Study
What a definition is not
A definition is SPEQ’s plain-language decode of how a term is used in practice, cited to the documents that define it. It is a practitioner reference, not legal or regulatory advice, it does not replace the definition in the source, and where a regulator’s wording differs the regulator’s wording governs.
A structured, guideword-driven team review of a process design that examines each node for deviations — no flow, more pressure, reverse flow — and their causes, consequences and safeguards. Primarily a process-safety technique, it frequently surfaces product-quality risks that a quality-only assessment misses.
A HAZOP is a structured team review that walks a design node by node, applying guidewords — no flow, more pressure, reverse flow, less temperature — to surface deviations, then examining each for cause, consequence and safeguard. It is a process-safety technique by origin, and its discipline is what makes it useful: the guidewords force consideration of failures nobody would have raised spontaneously.
It earns its place in a quality programme because many of those deviations have product consequences rather than safety ones. Reverse flow in a transfer line raises cross-contamination; loss of pressure differential raises contamination ingress; a failed interlock permits a sequence that no cleaning validation covered. A quality-only risk assessment tends to start from known quality failure modes and so rarely reaches these.
The output is only as good as the follow-through. HAZOP generates actions, and the value is realised when they are tracked to closure and when the safeguards claimed during the study are verified to exist — a study that credits an interlock nobody subsequently confirmed has documented an assumption.
- —Guideword-driven, node-by-node examination of deviations, causes, consequences and safeguards.
- —Process-safety in origin; frequently surfaces cross-contamination and contamination-ingress risks.
- —Reaches failure modes a quality-only assessment starting from known modes does not.
- —Value depends on tracking actions to closure.
- —Safeguards credited in the study must be verified to exist, or the study recorded an assumption.
IEC 61882 for HAZOP methodology; ICH Q9(R1) for quality risk management to which its findings feed.
Frequently asked questions
What does HAZOP stand for?
HAZOP stands for Hazard and Operability Study.
What is HAZOP?
A structured, guideword-driven team review of a process design that examines each node for deviations — no flow, more pressure, reverse flow — and their causes, consequences and safeguards. Primarily a process-safety technique, it frequently surfaces product-quality risks that a quality-only assessment misses.
Which regulations cover HAZOP?
IEC 61882 for HAZOP methodology; ICH Q9(R1) for quality risk management to which its findings feed.