A facility can run safely for years and still drift away from its original design intent. Not because people are careless, but because real life happens: new product lines get introduced, equipment gets upgraded, workarounds become “the way we do it,” and documentation quietly falls behind.
That is exactly why one of our long standing design clients asked IDEA to complete a Re-HAZOP study for their production facility in South West England. It had been a long time since a full, end to end assessment had been carried out. In the meantime, several major projects had introduced significant changes. Each project had been risk assessed individually, but a holistic view of the full facility had never been completed to ensure consistency with current standards and a single, aligned approach to process safety.
What followed was four days of focused workshops with fantastic engagement from engineering and operations teams, and a set of clear, practical actions aimed at reducing the likelihood of process safety incidents across the whole site.
Client Snapshot and Site Context
This client is one of IDEA’s key design partners, operating a busy production facility with multiple process areas and a mix of legacy equipment and newer installations. Like many established sites, the facility has evolved over time. Projects were delivered to improve capacity, reliability, and capability, and the business introduced new product lines that changed the operating envelope for some materials and conditions.
This is a common scenario. The site is not “unsafe,” but it is also not frozen in time. When changes accumulate, risk can shift in subtle ways. A Re-HAZOP provides the reset button that brings everyone back to a shared understanding of how the plant is meant to operate, what has changed, and where the hidden gaps are.
The Challenge: Change Over Time and Lost Design Intent
Here is the tricky part about long running plants: they often work so well that nobody notices the slow drift.
Over time, teams naturally optimise. They solve problems, keep production moving, and adapt to constraints. But those adaptations can create a mismatch between design assumptions and actual operating practice. When that mismatch is not captured and controlled, it can lead to:
- Inconsistent safeguards across different process areas
- Unclear operating boundaries for new products or changed conditions
- Manual tasks with higher human reliance than originally intended
- Procedures that no longer reflect real operating steps, including maloperations
- Domino effects that are not obvious when you only assess projects in isolation
The client’s management team recognised this and made a deliberate decision: “Let’s step back and re-align the whole facility with current standards, not just individual projects.”
Why a Re-HAZOP and Why Now
A Re-HAZOP is not just repeating old work. It is a structured way to answer a very practical question:
Are we still operating this facility in line with the intent, and if not, do we fully understand the risks and controls?
The timing was right for three reasons:
- Significant cumulative changes had been implemented through multiple projects
- New product lines had altered what materials were handled and under what conditions
- A long gap existed since the last full site wide hazard review, meaning standards, expectations, and best practice had moved on
In other words, this was about building confidence. Not only that the plant works, but that it works safely, consistently, and defensibly.
Project Objectives and Success Criteria
The Re-HAZOP study was designed around clear goals:
- Re-establish a consistent process safety baseline across the whole facility
- Identify deviations from original design intent and understand their impact
- Confirm the suitability of safeguards against current operating conditions
- Highlight documentation gaps, especially around new products and updated operating practices
- Capture practical actions with owners and priorities to support close out
- Strengthen alignment to current standards and internal expectations
Success was not measured by the number of actions generated. It was measured by clarity. Everyone should leave knowing what has changed, what matters, and what needs fixing first.
IDEA Approach: A Practical, Process Led Re-HAZOP
We keep our approach grounded. A Re-HAZOP should be rigorous, but it should also be usable. If the output is a report that sits on a shelf, it has failed.
Pre-Workshop Preparation and Document Review
Before the workshop, IDEA worked with the client team to gather and review available information, typically including:
- Process safety information, drawings, and basis of design where available
- Operating procedures and key operating envelopes
- Records of recent modifications and changes
- Incident and near miss learnings where relevant
- Equipment and control philosophies across key systems
This stage matters because it helps identify where knowledge is strong and where it lives only in people’s heads. That is often where risk hides.
Defining Scope, Nodes, and Deviations
We then structured the Re-HAZOP into clear nodes that reflected how the plant is actually operated. This is a subtle but important point. If you define nodes in a way that looks tidy on a drawing but does not match reality, you lose the room fast.
We aligned on:
- Study boundaries
- Node list and rationale
- Guidewords and deviation set
- Interfaces between systems where domino effects can emerge
Establishing Safeguards and Performance Standards
A safeguard is only a safeguard if it is understood, maintained, and capable of doing its job. During the study, we focused on:
- What prevention and mitigation layers exist today
- Whether they still apply under new products and operating conditions
- Whether they rely heavily on human action and whether that is realistic
- Where documentation and competency gaps could weaken control
This is where a Re-HAZOP becomes more than a paperwork exercise. It becomes a reality check.
Workshop Delivery: Four Days of High Engagement
The Re-HAZOP was delivered over four full days. The engagement level was excellent, and it made a real difference. When operations and engineering are both present and fully involved, you get two things that are hard to fake:
- The real story of how the plant is run
- The engineering lens on what was assumed and what is now true
Who Was in the Room and Why It Mattered
One of the strongest signals in this project was the collaborative mindset. Operations teams do not always get the space to step back and look across the whole process. When they do, the insights are huge.
It is like zooming out on a map. You might know your street perfectly, but you only spot the bottlenecks when you see the whole city.
How We Captured Deviations and Actions
We structured each node discussion so the team could move logically through:
- Deviation
- Causes
- Consequences
- Existing safeguards
- Recommendations and actions
We kept actions practical and assignable, with clear intent and priority.
Keeping Momentum Without Missing Detail
Four days is long enough to go deep, but short enough that focus matters. We kept sessions energetic by:
- Using a consistent structure and pace
- Parking detailed technical follow ups without losing them
- Checking alignment regularly so the team stayed on the same page
- Making sure the output felt useful, not abstract
What We Found: The Patterns Behind the Deviations
Every site is unique, but patterns repeat across industry. In this case, several themes stood out.
Whole Process Visibility Gaps
One of the biggest insights was simple: operations teams rarely get the chance to look across the entire facility and ask, “Does this all still line up?”
As projects happen, individual areas get optimised. But interfaces can become messy. The Re-HAZOP created a structured forum to uncover inconsistencies and make them visible.
Product Changes Not Fully Documented
New product lines had been introduced over time, changing the parameters for materials handled. The reality on the ground had evolved faster than the documentation.
This matters because the hazard profile of a system can change when materials or conditions change. Even if the equipment is the same, the risk may not be.
The Re-HAZOP helped identify where the documentation trail needed to catch up so the site had a defensible and shared record of what is actually being processed.
Manual Operations and Outdated Procedures
We found operations with a high reliance on manual activities, where procedures had not been updated to reflect how tasks are really carried out.
That is a big deal. A procedure is not just a training document. It is part of the safety barrier system. If it does not reflect reality, it cannot reveal maloperations, and it cannot reliably guide people during abnormal conditions.
This theme often links to human factors risk. If a step is performed differently in practice, the risk is not theoretical. It is live.
Site Wide Hazards and Domino Effects
A Re-HAZOP provides a perfect chance to review hazards across the facility, including potential domino effects, especially in light of recent incidents or near misses.
Even where individual projects were assessed, the combined picture can look different. Interactions between systems, utilities, and shared safeguards can introduce dependencies that are not obvious when you only look at one change at a time.
Key Outcomes and Value Delivered
The value of this Re-HAZOP was not just identifying issues. It was creating a clearer, shared understanding and a practical plan to strengthen process safety.
Clear Actions, Owners, and Next Steps
The output included a set of recommendations that the site can progress through close out. The focus was on actions that are:
- Clear in intent
- Assigned to the right owner
- Prioritised based on risk
- Suitable for tracking and verification
Stronger Alignment to Current Standards
The client’s goal was to re-align with current standards. The Re-HAZOP provided a structured method to bring the whole site back to a consistent baseline.
That baseline matters for governance, future projects, and regulatory confidence.
Improved Operability and Day to Day Confidence
A hidden benefit of a good Re-HAZOP is confidence. When teams understand the process more clearly and know where the risks and controls sit, day to day decisions improve.
People stop relying on tribal knowledge and start relying on shared, documented understanding.
Lessons Learned for Similar Facilities
If your site feels familiar, these lessons will probably hit home.
Small Changes Add Up
A dozen “small” modifications over five years can change a facility more than one major project. The risk is not in the changes. It is in the gaps between them.
Documentation Is a Safety Barrier Too
It is tempting to treat documentation as admin. But in process safety, documentation is part of control. If you cannot explain what you are running and why safeguards are appropriate, you are exposed.
What Happens After the Re-HAZOP
A Re-HAZOP creates value when actions are closed out properly.
Action Close Out and Verification
The next step is typically to track actions through to completion, including verification that:
- The change has been implemented as intended
- The safeguard or procedure works in practice
- Training and competency needs are addressed
- The updated information is embedded in the site’s process safety information
Management of Change Integration
One of the best outcomes is using the Re-HAZOP findings to strengthen Management of Change. When MoC is robust, you reduce the chance of drift returning.
Why IDEA
IDEA brings a process led, practical approach to process safety studies. We are used to working with operational teams, engineering teams, and leadership to translate risk review outputs into actions that actually get done.
We focus on consistency, clarity, and outcomes, not just compliance language.
Get in touch with IDEA to arrange a short discovery call.
If your site has seen multiple upgrades, new product introductions, or gradual operational workarounds, a Re-HAZOP can be one of the highest value process safety activities you do.
Want to sense check whether your facility is due for a Re-HAZOP, or talk through scope and approach? We will help you define the right study boundaries, the right people to involve, and the quickest path to a practical output your team can use.
Conclusion
This Re-HAZOP study in South West England was a timely reset. The facility had evolved through multiple projects and operational changes, and the management team made the right call to step back and take a holistic view. Over four highly engaged workshop days, we uncovered where operations had drifted from original design intent, where product changes were not fully documented, where manual tasks relied on outdated procedures, and where site wide hazards and domino effects needed a fresh look. The result was a worthwhile, practical set of outcomes aimed at lowering the risk of process safety incidents across the facility and building a stronger, consistent baseline for the future.
FAQs
1. What is a Re-HAZOP and how is it different from a HAZOP?
A Re-HAZOP is a structured revalidation of an existing facility, focused on what has changed since the original HAZOP, how the plant is actually operated today, and whether safeguards still match current conditions and standards.
2. When should a site consider a Re-HAZOP?
Common triggers include multiple cumulative modifications, new products or materials, a long gap since the last full review, or a desire to re-align with modern expectations and internal governance.
3. How long does a Re-HAZOP typically take?
It depends on scope and complexity, but many studies are delivered as multi day workshops supported by preparation and follow up documentation and action tracking.
4. Who should attend the Re-HAZOP workshops?
A strong mix of operations, engineering, maintenance, and process safety stakeholders is ideal. The best results happen when people who know the real operation are in the room alongside technical owners.
5. What are the usual outcomes of a Re-HAZOP?
Typical outcomes include updated understanding of hazards, confirmation or improvement of safeguards, updated procedures and documentation, and a prioritised action list with owners and next steps.