Hazardous Area Design
Turn the classification into a practical design.
Hazardous area design support for new projects, existing plant upgrades and remediation. Select suitable Ex equipment, define installation requirements and prepare the documentation your project and operations teams need.
Gas + dust
Both hazard types considered
Site conditions
Process and release assessment
Zone drawings
Clear boundaries and extents
Change control
Change controlA basis for future review
When you need this
New plant.
Changed processes.
Unclear hazardous zones.
Start with the areas or changes you need to understand. Select anything that applies to your site.
Outcomes & business value
Clarity for the people designing, building and operating your plant.
Understand the boundaries
Make the hazardous area visible on your drawings, so project and operations teams can work from an agreed classification.
Inform equipment decisions
Identify the required Equipment Protection Levels (EPLs) and relevant classification parameters for the next stage of design.
Manage change with confidence
Keep a traceable record of the conditions behind the zoning, making it easier to identify when a change needs engineering review.
Scope & typical deliverables
From the process information to the classification dossier.
We agree the areas, substances, available information and required outputs before the work begins.
Review the documentation
Assess process and instrumentation diagrams (P&IDs), layouts, safety data sheets (SDS), operating conditions and existing hazardous area records.
Confirm conditions on site
Walk down the agreed areas to check release sources, ventilation, bunding, drainage and equipment locations against the available documentation.
Assess releases and determine zones
Evaluate release grades and ventilation or dispersion conditions. Determine the appropriate zone categories and their extents, with assumptions and limitations recorded.
Document the classification
Prepare the report and drawings, identify equipment protection requirements, and record information gaps or actions for follow-up.
What you receive
A classification your team can use and maintain.
- HAC report with the assessment basis and zoning rationale
- Zone drawings in PDF and CAD/DWG as agreed, including sections or elevations where needed
- Register of substances and release sources
- Equipment Protection Level requirements and selection guidance
- Recorded assumptions, information gaps and follow-up actions
Plan the next stage: detailed hazardous area design, equipment verification and formal audits can be scoped alongside the classification where required.
Engagement options
Start with the level of assessment your site needs.
01 / Engagement option
HAC Gap Assessment
Review what is already available, with a targeted site walkdown to identify missing information and define the next stage.
02 / Engagement option
Full HAC
Develop a complete classification package for the agreed plant areas, from the site assessment through to the report and drawings.
03 / Engagement option
HAC Update / MOC Review
Revisit the classification after plant changes and update the affected drawings, assumptions and records.
Our approach
A defined path from site information to handover.
Agree the areas and the purpose
Confirm whether you need a gap assessment, a full classification or a review after a change. Agree the site boundaries, document formats and information required.
Build the process picture
Review the available records with your team and identify what needs to be checked during the site visit. Record missing information for follow-up.
Connect the assessment to the operating plant
Check the agreed areas on site, then assess the relevant release and atmospheric conditions. Keep the reasoning behind the classification traceable.
Make the findings usable
Bring the assessment together in the zone drawings, report and supporting registers, with clear references between the outputs.
Explain the basis and the open actions
Review the findings with your team, confirm outstanding actions and identify the changes that would trigger a future classification review.
Across the assets you operate
- Mining & Industrial
Why RelyOn?
Connected engineering support.
From classification through to the next project decision.
Keep the classification connected to the work that follows.
Your zoning is a starting point for equipment selection, installation and ongoing management. RelyOn brings hazardous area classification together with related design, audit and electrical safety services, so the next scope can build on the same engineering basis.
Related hazardous area services
Hazardous Area Design
Translate the classification into equipment and installation requirements.
Hazardous Area Audits
Plan the inspection, documentation review and close-out of findings.
FAQ's
Before you scope a classification.
Do you assess both gas and dust hazards?
Yes. The scope can cover gas and vapour zones, combustible dust zones, or a site with both. We confirm the relevant assessment method and information needed for each hazard.
Can you use our existing classification dossier?
Yes. Existing reports and drawings are a useful starting point. We review their basis against the current plant and identify where the classification or supporting information needs to be updated.
Can the drawings fit our document control system?
PDF and CAD/DWG outputs can be agreed at scoping. Existing drawings can also be marked up or updated, with the required drawing format and revision conventions confirmed before issue.
What if our site information is incomplete?
Start with the records you have. We use the review and site walkdown to identify what is missing, then document the information requests and any limitations. Where a missing input affects the assessment, it needs to be resolved before that part of the classification can be finalised.
When should the classification be reviewed?
Review it when materials, operating conditions, ventilation or layout change in a way that could affect the hazardous atmosphere. Periodic reviews should also reflect the site risk and how frequently the plant changes.
Does classification include detailed design or an audit?
Classification establishes the zoning and the associated assessment basis. Detailed equipment selection, installation design and formal audits are related services with their own outputs and scope. Tell us about your project stage so these can be planned together.
Start with your site
Need to define or review your hazardous areas?
Share your process information, existing classification or proposed plant change. We’ll help establish the assessment and documentation you need.
Prefer to speak with the team?
1300 15 66 85
