What this is
What is an explosive atmosphere zoning record?
What is an explosive atmosphere zoning record?
A record that identifies where flammable dust, vapour or gas can form an explosive atmosphere with air, classifies the extent and likelihood of that atmosphere into zones, and states what electrical and mechanical equipment is permitted in each zone as a result. It is the working document behind hazardous area classification.
What do the zone numbers mean?
Zones describe how often and for how long an explosive atmosphere is expected to be present, not how severe an explosion would be. Gas and vapour atmospheres use zones 0, 1 and 2 in descending order of persistence; dust atmospheres use zones 20, 21 and 22 on the same logic. A zone 0 or 20 area is expected to have the atmosphere present continuously or for long periods.
Who can carry out a zoning assessment?
A person competent in hazardous area classification, which is a distinct competence from general safety assessment. It requires understanding the release sources, the ventilation regime and the classification methodology well enough to justify a zone boundary that will be relied on for equipment selection, not just to tick a box that an assessment occurred.
Scope
When is an explosive atmosphere zoning record required?
Zoning is the classification instrument, and its boundary is with the substance-level and equipment-level records either side of it. Using it to do their job leaves gaps that surface only when equipment or a substance is checked in isolation.
Use this template when
- A new area, process or piece of equipment could release a flammable dust, vapour or gas
- An existing zoned area has changed in substance, throughput, ventilation or layout
- Equipment is being specified or purchased for an area that may carry an explosive atmosphere
- A dust or vapour source has been identified that was not previously assessed
- The explosion protection document needs a current classification to reference
Do not use it for
- Dust Hazard Assessment, which quantifies the combustibility and explosibility of a specific dust rather than classifying the areas it is handled in
- Chemical Substitution Assessment, which is used when a flammable substance is being replaced rather than zoned in place
- Restricted Substance Compliance Record, which tracks regulatory restriction on a substance, not the physical explosion risk of handling it
- Risk Assessment, which is the general instrument and will not carry the classification methodology a zoning decision needs
- Electrical inspection records, which verify installed equipment against its rating rather than establishing what rating the area requires
Compliance mapping
Which ISO 45001 cl.6.1.2 requirements does this satisfy?
Zoning sits inside a small family of instruments unusually specific for safety documentation: the methodology, the equipment categories and the marking requirements are all prescribed.
| Clause | Requirement | Where it lands |
|---|---|---|
| ATEX 1999/92/EC art.4 | Classification of places where explosive atmospheres may occur into zones | Identification |
| IEC 60079-10-1 / 60079-10-2 | Methodology for determining zone extent from release source, rate and ventilation | Identification |
| ATEX 2014/34/EU | Equipment and protective systems intended for use in potentially explosive atmospheres carry a category matched to the zone | Equipment |
| OSHA 29 CFR 1910.307 | Electrical equipment and wiring in hazardous (classified) locations installed and marked to the location's classification | Equipment |
| DSEAR 2002 | Places classified into zones marked at their points of entry | Management |
| ATEX 1999/92/EC art.7 / Annex II | Explosion protection document setting out the classification, the measures taken and their adequacy | Outcome |
| ISO 45001 cl.6.1.2 | Hazard identification proactive and ongoing, extended here to release sources and ignition sources | Header |
| ISO 45001 cl.8.1.2 | Elimination of hazards and reduction of risk, applied here to static control and earthing as engineering controls | Equipment |
What it does not cover
- Dust Hazard Assessment, which characterises the combustibility of the material itself and belongs alongside, not inside, the zoning record.
- Chemical Substitution Assessment, which is the route for removing a flammable substance rather than classifying the area it is used in.
- Restricted Substance Compliance Record, which addresses regulatory restriction on a substance and carries no explosion protection content.
- A general Risk Assessment, which cannot substitute for the classification methodology a competent zoning assessment applies.
- Hot work permit, which controls a single activity against zones that this record has already established, not the other way round.
Global
Explosive Atmosphere Zoning Record requirements by country
The duty to classify is close to universal wherever flammable dusts, vapours or gases are handled, but the three regimes differ in how prescriptive the equipment and marking rules are.
OSHA 29 CFR 1910.307; NFPA 70 (NEC) Articles 500–506
Hazardous (classified) locations divided into classes and divisions, or zones under the NEC's alternative scheme, with equipment matched to each.
The class/division and zone systems coexist in US practice, and a record must state which one it uses rather than mixing terminology.
DSEAR 2002, implementing the ATEX workplace directive
Places classified into zones, marked at entry points, with an explosion protection document required.
The explosion protection document is the enforceable output; a zoning record without one is an incomplete implementation of the duty.
ATEX 1999/92/EC (workplace); ATEX 2014/34/EU (equipment)
Two directives cover the same subject from opposite ends: the workplace directive requires classification, the equipment directive sets equipment categories.
A zone is meaningful only once matched against the equipment directive's category system, which is why the two are cited together.
How to complete it
How to complete an explosive atmosphere zoning record, step by step
The template prompts for a classification and a set of yes/no equipment checks. What makes the record defensible is the reasoning connecting the release source to the zone, and keeping equipment decisions downstream of that reasoning rather than ahead of it.
Equipment is frequently ordered, or already installed, before the zone extent is formally determined, on the assumption that whatever was specified last time will do again. Recording equipment suitability without a documented zone behind it inverts the logic the methodology depends on.
A single area can contain several release sources with different grades, and the zone extent follows each source rather than the room boundary. Classifying a room as one zone usually understates the extent around the actual source and overstates it everywhere else.
Fixed equipment gets checked once and stays checked. Phones, tools and trucks that move in and out of a zoned area cause the most incidents, because nothing in a static equipment register controls them without a written rule naming what is permitted to enter.
The document is where the classification, the equipment measures and their adequacy are argued together. A zoning record with the boxes ticked and no document behind it has produced data without the reasoning that makes it defensible after an incident.
What auditors find
Most common explosive atmosphere zoning record findings
Zoning findings rarely concern whether a record exists. They concern whether the zone still describes the area, and whether the equipment in it still matches the zone.
| Finding | Clause | What fixes it |
|---|---|---|
| Equipment installed or purchased before the zone extent was determined. | ATEX 2014/34/EU | Hold equipment specification against a current classification, not a prior installation's assumption. |
| Zone not reassessed after a change to substance, throughput or ventilation. | ATEX 1999/92/EC art.4 | Link the zoning record to management of change so a process change raises the review automatically. |
| Portable equipment or vehicles entering a zoned area without a written control. | DSEAR 2002 | State which portable items and vehicles are permitted in each zone and how that is enforced at the boundary. |
| Zone boundaries not marked at points of entry. | DSEAR 2002 | Install signage at every entry point to a classified zone, not only the obvious ones. |
| Explosion protection document absent or not updated alongside the classification. | ATEX 1999/92/EC art.7 | Produce or update the document as part of closing the record, not as a separate exercise. |
| Static control and earthing not verified for equipment handling flammable powders or liquids. | ISO 45001 cl.8.1.2 | Verify earthing and bonding continuity as part of the assessment, with a record of the check. |
Case in point
Case in point: the zone that was correct when it was drawn
A dairy classified its milk powder handling area on installation, assigning zone 22 around the filling head and equipment rated accordingly. The classification was competently done and matched the original throughput.
Three years later the site added a second filling line beside the first, sharing the same room. Nobody revisited the zoning, because the project was run as a capacity upgrade by production engineering, and the zoning record belonged to safety. The new line's release source extended the zone 22 boundary well past where the original equipment specification assumed it stopped, and standard-rated equipment was installed inside the extended boundary unclassified.
The template
The template, field by field
The form exactly as it installs. Every field, option, score and conditional rule is editable, and the links to other templates come with it.
6 sections
- Reference
- ENV-050
- Archetype
- Assessment
- Record ID
- EAZ-2026-000
- Scoring
- Zones compliant
- Direction
- High is good
- Singleton
- Yes
- Basis
- ISO 45001 cl.6.1.2
- Links
- Links Combustible dust, Electrical
- Tags
- Chemicals, Explosive
- Sections
- 6
- Fields
- 47
- Follow up fields
- 3
- Repeating sections
- 0
- Links out
- 5
Header
12 fieldsAssessment ID*
Auto sequence. Format EAZ-2026-000.
The record's own ID. Other templates point at this value.
Status*
Drives who this goes to next.
- Planned2 pts
- In progress2 pts
- Complete3 pts
- Deferred0 pts
- Open0 pts
- Closed3 pts
- Overdue0 pts
Date and Time*
Completed By*
Site*
Site ID*
Format SITE-000.
Links to FDN-001 Site ID
Area
The area within the site.
Exact Location
Drop a pin for anything hard to find.
Area Or Equipment*
Atmosphere Type*
Assessor Competent*
- Yes3 pts
- Partly1 pt
- No0 pts
Flour, Sugar And Cleaning Solvents All Create Zones
Sites assume explosive atmospheres are a chemical plant problem. A flour silo, a sugar handling bay and a solvent store all create zones that dictate what equipment may be used.
Identification
6 fieldsFlammable Materials Identified*
- Yes3 pts
- Partly1 pt
- No0 pts
Release Sources Identified*
- Yes3 pts
- Partly1 pt
- No0 pts
Frequency And Duration Of Release Assessed*
- Yes3 pts
- Partly1 pt
- No0 pts
Ventilation Effectiveness Assessed*
- Yes3 pts
- Partly1 pt
- No0 pts
Zone Classification Assigned*
- Yes3 pts
- Partly1 pt
- No0 pts
Zone Extent Determined*
- Yes3 pts
- Partly1 pt
- No0 pts
Equipment
6 fieldsEquipment Category Suitable For Zone*
- Yes3 pts
- Partly1 pt
- No0 pts
Equipment Marked And Documented*
- Yes3 pts
- Partly1 pt
- No0 pts
Portable Equipment Controlled*
- Yes3 pts
- Partly1 pt
- No0 pts
Vehicles Excluded Or Suitable*
- Yes3 pts
- Partly1 pt
- No0 pts
Static Control Measures In Place*
- Yes2 pts
- No0 pts
- N/Aexcluded from denominator
Earthing And Bonding Verified*
- Yes3 pts
- No0 pts
Management
6 fieldsZones Marked On Site Plan*
- Yes2 pts
- No0 pts
- N/Aexcluded from denominator
Signage At Zone Boundaries*
- Yes3 pts
- Partly1 pt
- No0 pts
Hot Work Prohibited Or Controlled*
- Prohibited4 pts
- Permit controlled3 pts
- Uncontrolled0 pts
Workers Trained On Zones*
- Yes3 pts
- Partly1 pt
- No0 pts
Contractors Briefed On Zones*
- Yes3 pts
- Partly1 pt
- No0 pts
Documentation Available And Current*
- Yes2 pts
- No0 pts
- N/Aexcluded from denominator
Related records
1 fieldRestricted Substance ID
Substances relevant to the zoning.
Links to ENV-049 Record ID
Outcome
16 fieldsClassification Complete*
- Yes3 pts
- Partly1 pt
- No0 pts
Non Compliant Equipment Items*
Immediate Risk*
- No3 pts
- Yes0 pts
Explosion Protection Document Updated*
- Yes3 pts
- Not required3 pts
- No0 pts
Dust Assessment ID
Links to SAF-175 Assessment ID
Next Review Due*
Risk Assessment
Risk ID
Format RSK-2026-00000.
Links to FDN-012 Risk ID
Action Required*
Raise the action record, then enter its reference here.
- No2 pts
- Yes0 pts
Priority
- High0 pts
- Medium1 pt
- Low3 pts
CAPA ID
Format CAPA-2026-00000.
Links to FDN-014 CAPA ID
Action Owner
Assessor*
Signature*
Engineering Manager*
Second Signature*
ENV-050 · record IDs look like EAZ-2026-000 · Links Combustible dust, Electrical
Open in KnowellaRun it with agents
From a document you fill in to a programme that runs itself
The classification is easy to get right once. What fails is noticing the process change that should trigger a new one, and keeping the equipment register in step with the zone.
Holds the zoning record against the site's substance and equipment registers, and flags equipment that no longer matches its zone.
Connects equipment category requirements to the maintenance schedule, so a zoned item's rating is verified on the same cycle as its condition.
Links hot work permits and contractor briefings to the current zone map, rather than a version last printed at the workface.
Watches management of change and layout records for events that should trigger a re-zoning, and raises the review before the register drifts out of step.
This template lives in KnowEnviro — environment and energy. Aspects, permits, waste, emissions, spills and sustainability reporting.
Meet KnowEnviro→Glossary
Explosive Atmosphere Zoning Record definitions and key terms
- Zone
- A classification of an area by how often and for how long an explosive atmosphere is expected to be present, using 0/1/2 for gas and vapour and 20/21/22 for dust.
- Release source
- A point or surface from which a flammable dust, vapour or gas can escape into the atmosphere, and the feature that determines a zone's extent.
- Equipment category
- The rating under the equipment directive that states which zone a piece of electrical or mechanical equipment is permitted to operate in.
- Explosion protection document
- The record setting out the classification, the measures taken to control ignition sources, and the adequacy of those measures for the zones identified.
- Zone extent
- The distance a classified atmosphere is judged to reach from its release source, determined by release rate, grade and ventilation rather than by room boundary.
FAQ
Frequently asked questions about explosive atmosphere zoning record
Do ordinary food or logistics sites need zoning records?+
Yes, wherever a combustible dust, flammable solvent or fuel vapour is handled in quantity. Flour, sugar, milk powder and cleaning solvent all generate atmospheres capable of being classified, and assuming zoning is a chemical-plant concern is the single most common reason it gets skipped.
Can one person both classify the zone and select the equipment?+
Yes, but the two decisions must be recorded as sequential rather than combined, because equipment selected without a documented zone in front of it cannot later be shown to have followed the classification rather than preceded it.
What triggers a re-zoning rather than a routine review?+
Any change to the substance handled, the throughput, the layout or the ventilation regime. A stated review interval is a backstop for change nobody flagged, because a zone correct on the review date can be wrong within weeks of a process change.
Does portable equipment need to be zoned separately from fixed equipment?+
Yes. Fixed equipment is installed once against a known zone and checked periodically. Portable tools, phones and vehicles move between zoned and unclassified areas and need an explicit rule, because a static equipment register does not control something that moves.
Is the explosion protection document the same thing as the zoning record?+
No. The zoning record establishes the classification; the document is the wider argument that classification, ignition-source controls and equipment measures together are adequate. A site needs both, and the document should reference the current record rather than restate it.
How is zone extent actually calculated?+
From the release source's grade, rate and the ventilation diluting it, following a methodology such as IEC 60079-10. It is not a fixed distance applied uniformly, and assigning the same extent to every source regardless of its release characteristics has not applied the methodology.
Keep going
Related templates and programmes
Industries this is written for
Programmes this belongs to
Used together in Chemical Safety and WHMIS
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Chemical Substitution Assessment
Assesses whether a hazardous substance can be replaced by something safer, and what the substitute brings with it
Restricted Substance Compliance Record
Records compliance with restricted substance obligations covering ozone depleting gases, persistent chemicals and packaging materials
Chemical and Substance Register
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Chemical Inventory Record
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More in Chemicals and Substances
Chemical Substitution Assessment
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Restricted Substance Compliance Record
Records compliance with restricted substance obligations covering ozone depleting gases, persistent chemicals and packaging materials
Written and reviewed by
Siddarth Singh
Founder & Chief Executive Officer, Knowella
Certified Safety Professional and industrial and systems engineer with more than a decade inside food supply chain, freight and manufacturing operations. This page was written against the current text of the standards it cites, not against secondary summaries of them.
- Certified Safety Professional (CSP), Board of Certified Safety Professionals
- MBA, University of Chicago Booth School of Business
- MS and BS, The Ohio State University, Industrial and Systems Engineering
- Six Sigma Black Belt
Sources and last review. Reviewed 16 August 2026 against:
- ATEX 1999/92/EC — minimum requirements for improving the safety and health of workers potentially at risk from explosive atmospheres
- ATEX 2014/34/EU — equipment and protective systems intended for use in potentially explosive atmospheres
- DSEAR 2002 — Dangerous Substances and Explosive Atmospheres Regulations (UK)
- IEC 60079-10-1 / 60079-10-2 — classification of areas: explosive gas atmospheres / combustible dust atmospheres
- OSHA 29 CFR 1910.307 — hazardous (classified) locations
This page is general guidance, not legal advice. Confirm requirements with your jurisdiction’s regulator.