How Can Functional Safety Be Maintained During Operational Changes and Upgrades?

Operational changes and system upgrades are a normal part of any engineering environment. Equipment is replaced, processes are modified, and new technologies are introduced to improve efficiency and performance.

However, every change has the potential to introduce new risks. Maintaining functional safety during these transitions is essential to ensure that existing safeguards remain effective and that new hazards are properly understood and controlled.

A structured approach to managing change helps organisations maintain safety performance while adapting to evolving operational demands.

Why Change Creates Risk

Changes to a process can affect how systems behave in ways that are not always immediately obvious. Even minor modifications can alter operating conditions, introduce new failure modes, or reduce the effectiveness of existing safeguards.

For example, replacing equipment may change flow rates or pressures, while software updates to control systems can affect how safety functions respond under abnormal conditions.

Without proper review, these changes can create gaps in protection that may not become apparent until an incident occurs.

This is why maintaining functional safety during operational changes requires a clear and structured process that considers both technical and human factors.

The Importance of Hazard Identification

The first step in maintaining safety during change is effective hazard identification.

Hazard identification ensures that potential risks introduced by a modification are recognised before implementation. This process should not rely on assumptions or previous assessments. Instead, it should reflect the specific details of the proposed change.

Techniques such as HAZID are often used at an early stage to identify high-level hazards associated with new or modified processes. A HAZID review provides an initial understanding of where risks may arise and helps determine whether more detailed analysis is required.

Revisiting hazard identification during every stage of a change ensures that new risks are captured and managed appropriately. Structured process safety support can help ensure this is carried out consistently and aligned with real operating conditions.

Applying Structured Analysis Through HAZOP

For more complex changes, a HAZOP Study provides a detailed and systematic way to assess how deviations from intended operation could lead to hazardous outcomes.

A HAZOP Workshop brings together engineers, operators, and safety specialists to examine the process in detail. By applying guide words such as Flow, Pressure, Temperature, Level combined with deviations such as No, More, Less, Misdirected and Reverse, the team can identify potential deviations and explore their causes and consequences.

This structured approach is particularly valuable when modifying existing systems. It ensures that both design intent and operational reality are considered, helping teams identify risks that may not be obvious through informal review.

During the HAZOP Study, risks are often evaluated using HAZOP Risk Ranking. This helps organisations prioritise and focus on the most significant hazards and ensure that appropriate controls are implemented.

Evaluating Safeguards with Layer of Protection Analysis

Once hazards have been identified and analysed, it is important to assess whether existing safeguards are sufficient.

Layer of Protection Analysis provides a structured method for evaluating the effectiveness of independent protection layers. It helps determine whether the level of risk reduction achieved by existing systems meets acceptable criteria. It is usually applied to high-severity outcomes, such as potential fatality scenarios. 

During operational changes, Layer of Protection Analysis can be used to confirm whether modifications have impacted the reliability or independence of these safeguards. It can also identify where additional layers of protection may be required.

By applying this approach, organisations can ensure that functional safety systems continue to perform as intended, even as processes evolve. This is particularly important when managing complex systems, where a structured approach to functional safety ensures risks are properly controlled.

Managing Change in Practice

Maintaining functional safety during upgrades requires more than technical analysis. It depends on how change is managed in practice.

A robust Management of Change process ensures that all modifications are reviewed, documented, and approved before implementation. This includes assessing the impact of changes on safety systems, procedures, and operator responsibilities.

Key elements of effective change management include:

• Clear definition of the proposed change

• Structured hazard identification and risk assessment

• Review of existing safeguards and control measures

• Verification that safety systems will continue to perform as required

• Updating documentation and procedures

By following a consistent approach, organisations can maintain alignment between design intent and operational reality.

The Role of Proof Testing and Verification

Once changes have been implemented, it is essential to verify that safety systems are functioning as expected.

Testing plays a critical role in confirming that safety instrumented functions respond correctly under defined conditions. This may include functional testing, proof testing, and system validation.

Without verification, there is a risk that hidden failures or configuration issues may go unnoticed. Testing provides confidence that systems are capable of performing their intended safety functions when required.

Regular review and validation should be part of the ongoing lifecycle of any safety system, particularly following modifications or upgrades.

Maintaining Competence and Communication

Functional safety is not only about systems. It also depends on the people who operate and maintain them.

During operational changes, it is important to ensure that personnel understand how modifications affect the process and their responsibilities. This includes updating training, procedures, and communication channels.

A HAZOP Workshop or similar review process can also support knowledge sharing, ensuring that teams have a clear understanding of risks and controls.

Maintaining competence and clear communication helps ensure that safety systems are supported by effective human performance. Targeted functional safety training can help teams understand how systems behave during change and how to respond effectively.

How 6 Engineering Can Help

At 6 Engineering, we support organisations in maintaining functional safety throughout operational changes and upgrades.

Through our consultancy services, we support hazard identification through HAZID, facilitate HAZOP Workshops, and apply HAZOP Risk Ranking to prioritise risks effectively.

We also carry out Layer of Protection Analysis to ensure that safeguards remain robust and aligned with operational requirements.

By working alongside internal teams, we help ensure that changes are implemented safely, risks are properly understood, and safety systems continue to perform as intended.

If you would like to discuss how we can support your next project or modification, get in touch with our team.