HAZOP is one structured PHA method. It requires process knowledge, disciplined facilitation and a multidisciplinary team.

This guide is for career literacy, not a substitute for competent HAZOP facilitation.

PHA purpose

PHA asks:

  • What can go wrong?
  • Why?
  • What would happen?
  • What safeguards exist?
  • Is additional action needed?

When HAZOP is used

HAZOP is commonly used for process systems where deviations from intended operation can create significant hazards.

Application depends on sector, lifecycle stage and company/regulatory framework.

Nodes and deviations

A HAZOP divides the process into manageable study sections, often called nodes.

The team considers deviations from design intent using structured prompts.

The value comes from the team's process knowledge, not merely the guidewords.

Causes and consequences

For each credible deviation, examine:

  • initiating causes;
  • downstream consequences;
  • escalation;
  • affected people/assets/environment.

Avoid listing impossible causes simply to fill a worksheet.

Safeguards

Safeguards might include:

  • process controls;
  • alarms;
  • trips;
  • relief;
  • containment;
  • physical design;
  • procedures.

Whether a safeguard is credited in further risk analysis depends on the method.

Recommendations

Recommendations should address a real gap.

Good recommendations are:

  • specific;
  • assigned;
  • technically meaningful;
  • tracked to closure.

Team roles

A study may need:

  • operations;
  • process engineering;
  • maintenance;
  • instrumentation/control;
  • safety;
  • project/design knowledge.

The facilitator manages the method; the team provides expertise.

Documentation

A HAZOP record should preserve:

  • design intent;
  • assumptions;
  • scenarios;
  • safeguards;
  • recommendations;
  • unresolved questions.

Related methods can include:

CCPS describes LOPA as a semi-quantitative method for evaluating protection layers for a defined scenario.

Learning pathway

A developing process-safety professional can start by:

  1. learning process fundamentals;
  2. observing competent studies;
  3. understanding HAZOP terminology;
  4. learning safeguard quality;
  5. gaining supervised participation;
  6. developing facilitation only with sufficient experience.

HAZOP skill is not the ability to generate guideword combinations. It is the ability to help a competent team identify credible hazardous scenarios.

Related content

Sources