When A HAZOP Action Is “Closed” But the Risk Is Not!

The Issue We Keep Seeing.

In many HAZOP studies, particularly in asset-intensive industries, risk mitigation actions are recorded as: Maintenance Strategy to be performed or simply Maintenance Strategy.

The action is later marked closed – yet when we follow this through with clients, we often discover:

• No maintenance strategy has been agreed
• Tasks are generic
• Failure modes are not defined
• Inspection intervals are arbitrary
• Effectiveness has never been tested

The paperwork says the risk is mitigated. The reality says otherwise.

 Why This Matters?

HAZOP is a powerful hazard identification tool, but it is not a maintenance design methodology.

When a HAZOP action is closed without an effective maintenance strategy in place:

• Risk is administratively closed, not technically reduced
• Safety-critical failures remain credible
• Operations inherit hidden exposure
• The integrity of the HAZOP process is therefore weakened

This creates a dangerous illusion of control.

Where The Gap Exists?

HAZOP correctly identifies what needs to be controlled.

It does not define:

• How equipment actually fails
• Which failure modes dominate risk
• What task will prevent, detect, or mitigate those failures

That gap must be closed elsewhere.

Why FMECA Is The Missing Link?

This is where Failure Modes, Effects and Criticality Analysis (FMECA) adds real value.

FMECA converts a HAZOP recommendation into a verified safeguard by asking:

• What are the credible failure modes?
• What are the consequences if they occur?
• What task directly addresses each failure mode?
• Is the task technically effective?
• Is the task optimised for risk, cost, and safety?

Only when these questions are answered does a maintenance strategy become real risk control.

 A Better Way To Close HAZOP Actions.

If a HAZOP mitigation states “Maintenance Strategy”, then the action should only be closed when:

A documented strategy exists

• Tasks are linked to specific failure modes
• Intervals and techniques are justified
• Acceptance criteria are defined
• The strategy is implemented in the CMMS
• Ownership and governance are clear

Anything less is risk deferral, not risk reduction.

 HAZOP And FMECA Are Not Alternatives.

They are complementary:

• HAZOP identifies what could go wrong
• FMECA defines how we control it over the asset life cycle

Used together, they transform HAZOP from a study into a Sustained Risk Management System.

Final Thoughts.

If “maintenance strategy” is written into your HAZOP as a safeguard – ask yourself:

Has the risk actually been reduced, or have we just closed an action?

Because reliability and safety don’t come from good intentions – they come from failure-mode-driven action.

How PRS can help?

Contact Pro-Reliability Solutions to find out more about our FMECA training courses, or to discuss how we can help your organisation translate HAZOP intent into demonstrable, auditable risk control.

Gary Tyne – Director, Pro-Reliability Solutions