Overview
Hazardous area classification can feel a bit like updating an old map of a town that’s been quietly redeveloped for years. The streets are still there, but new buildings have gone up, old routes have changed, and some “danger zones” no longer make sense once you look closely.
That is exactly why our client, a distillery site, engaged Integro Design Engineering Associates (IDEA) to complete a site wide hazardous area classification (HAC) update study. The purpose was simple in principle: refresh the zoning assessment to reflect updated guidance since the last standard, and focus in on specific site areas that had become a concern over time.
The outcome was more than a refreshed set of drawings. It was a practical, defensible basis for specifying compliant equipment and ignition source controls, paired with real options to reduce unnecessary zone extent, especially in areas where blanket zoning had created operational and compliance challenges.
Client Context and Drivers for Change
Why hazardous area classification needed refreshing
Distilleries are dynamic sites. Process layouts evolve, ventilation strategies get improved, equipment gets replaced, and operational practices adapt. Over time, these changes can leave older hazardous area zoning studies out of step with reality.
In this case, the client’s previous zoning standard and assessment were no longer aligned with current expectations and guidance. This created a familiar problem: decisions about equipment and modifications were being made using an “old picture” of the risk.
The client wanted a refreshed HAC study that would stand up to scrutiny, support ongoing investment, and reduce uncertainty when planning upgrades, replacements, or maintenance.
The practical challenges of legacy zoning
Legacy zoning can also create very real headaches, especially when it results in large areas being classified more conservatively than necessary. If zone extents are bigger than they need to be, the knock on impacts can be significant:
- Higher cost of equipment and installation due to Ex requirements
- More constraints on maintenance and replacement activities
- Increased likelihood of non compliant legacy equipment remaining in place
- Added complexity in change management and future project delivery
Put simply, overly broad zoning can turn routine tasks into complex projects. The client wanted to understand what was truly required, and what could be improved in a safe, practical way.
Project Objectives
Refresh zoning based on updated guidance
The first objective was to update the zoning assessment using current guidance and good practice. That meant reviewing assumptions, validating releases, checking ventilation considerations, and ensuring that the final outputs were consistent and traceable.
Focus on key areas of concern
While the study was site wide, the client had several priority themes where they wanted a deeper review.
Internal rooms and constrained ventilation
Internal rooms can be challenging because ventilation performance is often less obvious, and the consequences of assumptions can be large. A small change in ventilation or release characteristics can shift the classification outcome materially.
We reviewed internal spaces carefully, ensuring that ventilation assumptions were evidenced, and that the zoning outcomes were practical and defensible.
Large Zone 1 areas
Large Zone 1 areas often trigger wider operational constraints, especially on existing sites where equipment has been installed over many years. The client wanted to understand whether large Zone 1 classifications were still justified, and what practical improvements could reduce extent without compromising safety.
Areas with improved ventilation since the last study
A key opportunity on many established sites is that ventilation has often improved since original zoning work was completed. That might be due to physical changes, operational changes, better extraction systems, or improved building layouts.
Where ventilation improvements existed, we assessed how these could influence zone extent and classification, and what evidence would be needed to support any changes.
Our Approach
How IDEA structured the study
IDEA delivered the study using a structured, risk based approach that balanced technical detail with practical site realities. We focused on:
- understanding hazardous releases, materials, and operating conditions
- assessing ventilation, confinement, and dispersion characteristics
- applying consistent zoning logic across the site
- ensuring documentation and rationale were clear and auditable
We treated the HAC update as a decision support tool, not just a compliance output.
Data gathering and stakeholder engagement
A good HAC study depends on the right inputs. We worked with site stakeholders to gather and verify:
- process and utility information
- equipment lists and known non compliances
- operational practices and maintenance routines
- drawings, layouts, and known modification history
This engagement helped align the assessment with how the site actually operates, rather than how it looks on paper.
Review of hazardous releases and ventilation assumptions
Ventilation is often the make or break factor in classification outcomes, particularly indoors. We reviewed existing ventilation provisions, air movement patterns, and the degree of enclosure or confinement.
Where assumptions required strengthening, we identified what evidence or actions would support a robust decision. This is important because HAC is not only about the answer, it’s about being able to explain the answer clearly.
Key Activities Delivered
Site walkdown and verification
A site walkdown was a core part of verifying zoning assumptions. It allowed our engineers to confirm:
- equipment arrangement and congestion
- ventilation features and potential dead zones
- practical separation and segregation opportunities
- areas where zoning had historically expanded beyond what was necessary
This step is where theory meets reality, and it is often where the best improvement opportunities appear.
Zoning updates and rationale
We refreshed the zoning classification across the site and provided updated outputs supported by clear rationale. This included reviewing:
- zone type selection
- zone extent justification
- key assumptions and limitations
- consistency across similar areas
The result was a clearer and more current zoning basis for the client.
Documentation and deliverables
A HAC update should be usable. Our outputs were structured so the client could confidently apply them to:
- equipment replacement decisions
- project scopes and specifications
- DSEAR compliance management
- contractor briefings and ignition source control
In other words, not a report that sits on a shelf, but one that supports day to day and project decision making.
Outcomes and Value Delivered
Clearer, more defensible zoning
The refreshed study provided a zoning assessment aligned with updated guidance and current site conditions. This strengthened the client’s compliance position and made future decisions more straightforward.
Reduced extent of blanket zoning in priority areas
One of the key benefits delivered was the ability to reduce significant blanket zoned areas in certain locations. This is often a major win on established sites, as it reduces constraints and improves the feasibility of upgrades.
We were able to offer solutions that helped the client reduce zone extent where justified, and provide guidance on further potential reductions, based on practical changes.
Practical route to address non compliant equipment
Retrospective HAC studies often reveal an uncomfortable truth: equipment that is not compliant may have been operating in areas that were historically over classified, or may be manageable through improvements.
In this case, we provided guidance to help the client move toward compliance in a practical way. That included identifying where zone reductions could help, and where ignition source control measures should be strengthened.
Differentiators
Turning compliance into options, not obstacles
A common frustration in hazardous area work is feeling boxed in by the classification. Our approach is different. We do not just label zones. We help clients explore feasible options that reduce risk and reduce unnecessary constraints.
That means thinking about what can be changed safely, rather than simply stating what the site must live with.
Zone reduction strategies we commonly apply
Zone reduction is not about “making risk disappear.” It is about applying good engineering and good evidence to reduce the likelihood of an explosive atmosphere forming, or reduce how far it can extend.
Here are practical strategies we often assess.
Increased ventilation
Ventilation improvements can reduce zone extent, particularly indoors. This may include local extraction, improved air changes, or changes that reduce stagnant areas.
Segregation and separation
Sometimes the simplest solution is to segregate a release source, or create effective separation. Physical barriers, improved enclosure strategies, or relocation of certain components can have a significant impact.
Engineering controls and operational measures
Engineering controls, better detection, interlocks, and improved operating practices can all reduce the probability or duration of hazardous atmospheres. Where operational measures are relevant, we ensure they are practical and supportable by site management systems.
Why DSEAR and HAC Studies Matter in Distilleries
Protecting people, assets, and production continuity
Distilleries handle flammable vapours and liquids as part of normal operations. DSEAR and hazardous area classification work are fundamental to preventing ignition and protecting:
- people working on site
- critical production assets
- long term operational reliability
Good process safety is not just about compliance, it is about keeping production stable and avoiding disruptive incidents.
Supporting correct equipment specification
HAC outputs directly influence how electrical and mechanical equipment is specified and installed. A current, well evidenced zoning study helps clients:
- select appropriate Ex rated equipment where required
- apply the right ignition source controls
- avoid over specification that increases costs unnecessarily
- reduce uncertainty in projects and maintenance planning
When the zoning map is right, everything downstream becomes easier.
How This Fits Into IDEA’s Wider Consulting Support
Process safety support alongside engineering design
While IDEA is widely known for engineering design services, we are also regularly engaged to provide broader engineering consulting and process safety support. DSEAR and HAC studies are a key part of that offering, particularly in the distillery sector where many clients need:
- HAC and DSEAR assessments to support projects
- retrospective zoning reviews on existing sites
- guidance on ignition source controls and compliance strategies
When clients typically engage us
Clients typically bring us in when they are:
- planning upgrades or expansions that require zoning clarity
- dealing with large historical zoned areas and legacy equipment
- responding to changes in standards and guidance
- looking for practical options to improve compliance without disrupting operations
This blend of engineering practicality and process safety rigour is where our team adds the most value.
Need a hazardous area classification study or DSEAR support for your distillery or process site? IDEA’s process safety engineers can deliver structured, defensible HAC studies and practical zone reduction options that support both compliance and operational efficiency.
Get in touch with IDEA to discuss your site needs and how we can support your next project.
Conclusion
A hazardous area classification update is more than a technical refresh. It is a chance to bring clarity to risk, remove unnecessary constraints, and create a stronger basis for investment and compliance.
In this project, IDEA delivered a site wide HAC update for a distillery client, aligned with updated guidance and focused on key concerns such as internal rooms, large Zone 1 areas, and areas with improved ventilation. By combining deep process safety experience with practical engineering thinking, we helped the client not only update zoning, but also identify realistic opportunities to reduce blanket zones and improve their route to compliance.
FAQs
1) What is hazardous area classification and why is it important?
Hazardous area classification identifies where flammable atmospheres may occur and defines zones so the correct equipment and ignition controls can be applied, supporting safety and DSEAR compliance.
2) How often should a distillery update its HAC study?
Updates are typically needed when site layouts, ventilation, operations, or guidance changes. Many sites also refresh studies as part of major projects or periodic compliance reviews.
3) Can zone extents be reduced on existing sites?
Yes, often. With the right evidence and practical engineering measures such as ventilation improvements or segregation, zone extents can sometimes be reduced without compromising safety.
4) How does HAC impact equipment selection?
The zone classification influences whether Ex rated electrical or mechanical equipment is required and what ignition controls must be applied, affecting cost, installation, and maintenance.
5) What makes a HAC study “defensible”?
A defensible study has clear assumptions, evidence for ventilation and release characteristics, consistent methodology, and traceable rationale so decisions can be explained and audited.