Why ‘Temporary’ Commissioning Changes Must Be Addressed Before They Become Permanent Problems

One of the most frequent — and dangerous — sources of reliability issues we encounter in operational plants is this:

temporary commissioning changes that were never fully reversed.

During commissioning, it is often necessary to:

• Override interlocks

• Disable certain alarms

• Adjust control setpoints for initial tuning

• Implement manual control steps to facilitate first operations

These changes are valid — for the short term.

But once the plant is live and handed over to the operations team, any commissioning modifications left in place can create major long-term risks.

The Problem

At BIA Engineering Ltd, we’ve seen many plants where commissioning overrides or temporary logic changes were forgotten or left undocumented.

The consequences?

• Critical alarms disabled or suppressed

• Manual control modes remaining active

• Control sequences bypassed

• Operators unaware of hidden risks in the system

This leads to:

• Unpredictable plant behaviour

• Increased reliance on operator intervention

• Masked faults that only reveal themselves under stress conditions

• Significant reliability and safety risk

A Real Example

At one energy plant, we discovered during a post-commissioning review that several key trip interlocks had been disabled during commissioning — and never restored.

Operators were unknowingly running the plant with major protection gaps — a situation that could easily have led to equipment damage or worse.

Our team:

• Identified all temporary changes through a structured controls audit

• Worked with plant engineering and operations to validate what should be restored

• Carefully re-implemented the proper logic and interlock configurations

• Ensured full system testing to confirm safe, reliable operation going forward

The Outcome

• Plant safety and reliability fully restored

• Operators regained trust in the control system

• Engineering documentation updated to reflect correct system status

Why It Matters

Commissioning is fast-paced and complex — but every temporary change must be properly documented and managed.

Failing to do this leaves plants exposed to reliability, performance, and safety risks long after handover.

Our Philosophy

At BIA Engineering Ltd, we advocate for:

• Structured commissioning close-out processes

• Full controls audit before operational acceptance

• Collaborative work with plant teams to ensure no hidden changes remain in place

Engineering solutions beyond expectations means helping plants build the foundations for reliable, safe, and sustainable operation — not leaving them exposed to unseen risks.

If your plant has not had a full post-commissioning controls review — it may be time to take a closer look.