Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. ATEX Zone 0, Zone 1, and Zone 2 classify hazardous areas based on the frequency and duration of explosive gas or vapor atmospheres. Zone 0 requires the most stringent equipment protection; Zone 2 allows broader equipment options. Selecting the correct zone classification for your camera installation determines which ATEX certification categories are legally required — and installing equipment below the required category is a safety violation regardless of the manufacturer’s claims.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
The Three ATEX Zones Explained
Zone 0: Continuous or Long-Period Hazardous Atmosphere
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Zone 0 is defined as a place where an explosive atmosphere in the form of a cloud of flammable gas, vapor, or mist is present continuously, for long periods, or frequently. In practice, Zone 0 exists almost exclusively inside enclosed spaces where flammable liquids or gases are stored or processed — the vapor space inside a storage tank, inside a process vessel, or above a liquid surface in a sump.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Zone 0 camera installations are uncommon because cameras are rarely needed inside vessels. When they are — for tank inspection, level monitoring, or process visibility — the only compliant option is intrinsically safe (Ex ia) equipment or equipment with special protection (Ex s). Explosion-proof (Ex d) enclosures are not permitted in Zone 0.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Zone 1: Likely Occurrence Under Normal Operations
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Zone 1 is the most common classification for external industrial surveillance in hazardous locations. It applies where an explosive atmosphere is likely to occur periodically during normal operations — around venting or breathing equipment, near pump seals and flanges that may release small quantities of flammable vapor, and in areas immediately surrounding Zone 0 spaces.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Zone 1 is where the vast majority of explosion-proof cameras are installed. Equipment for Zone 1 must be at least Category 2G (IEC 60079 Equipment Protection Level Gb), using an accepted protection concept: Ex d (flameproof), Ex e (increased safety), Ex ia or ib (intrinsically safe), Ex m (encapsulated), or Ex p (purged/pressurized).
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Zone 2: Unlikely Occurrence Under Normal Operations
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Zone 2 is where an explosive atmosphere is not likely to occur in normal operation and, if it does, will persist only for a short time. Zone 2 typically surrounds Zone 1 areas as a buffer zone, or applies to areas where flammable substances are handled in sealed systems that could fail only through damage or abnormal operation.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Zone 2 allows Category 3G (EPL Gc) equipment in addition to all Zone 1-rated equipment. This opens up less expensive protection options including non-sparking (Ex nA) and restricted breathing (Ex nR) equipment that cannot be used in Zone 1.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Zone Comparison Table
| Factor | Zone 0 | Zone 1 | Zone 2 |
|---|---|---|---|
| Explosive atmosphere frequency | Continuous or long periods | Likely during normal operations | Only under abnormal conditions |
| IEC Equipment Category required | Category 1G (EPL Ga) | Category 2G (EPL Gb) | Category 3G (EPL Gc) |
| Acceptable protection concepts | Ex ia, Ex ma, Ex s only | Ex d, Ex e, Ex ia, Ex ib, Ex m, Ex p, Ex q | All Zone 1 methods + Ex nA, Ex nR, Ex ec |
| NEC equivalent (approximate) | No direct equivalent; Class I Div 1 Group A/B (most restrictive) | Class I Division 1 | Class I Division 2 |
| Common example locations | Inside tanks, vessels, sumps with flammable liquids | Around vents, pump seals, flanges; inside compressor buildings | Buffer zones around Zone 1, outdoor tank farms beyond vent radius |
| Camera options | IS micro-cameras, borescopes only | Full explosion-proof cameras, IS cameras | Explosion-proof, IS, purged/pressurized, non-sparking |
ATEX Gas Groups (IIC, IIB, IIA)
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Zone classification determines how likely the atmosphere is to be hazardous. Gas group determines which hazardous gas may be present, and therefore how demanding the equipment protection must be:
| Gas Group | Representative Gas | Industries | Equipment Compatibility |
|---|---|---|---|
| IIA | Propane | Oil and gas, LPG, fuel handling | IIA, IIB, or IIC equipment accepted |
| IIB | Ethylene | Chemical plants, plastics manufacturing | IIB or IIC equipment accepted (not IIA alone) |
| IIC | Hydrogen, acetylene | Semiconductor fabs, battery rooms, chemical synthesis | Only IIC equipment accepted |
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Most oil and gas facilities handle Group IIA gases (propane, methane, butane). IIB cameras are required for ethylene and similar chemical plant applications. IIC is the most demanding — equipment certified for IIC is always acceptable for IIB and IIA applications, but costs significantly more. Over-specifying the gas group is acceptable but expensive; under-specifying is a code violation.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Temperature Classes (T-Codes)
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. The T-code defines the maximum surface temperature the equipment can reach under any operating condition. This must be below the auto-ignition temperature of the specific gas present:
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
| T-Code | Max Surface Temp | Common Application |
|---|---|---|
| T1 | 450°C | Gases with very high ignition temps |
| T2 | 300°C | Acetylene applications |
| T3 | 200°C | Heavier fuel oils, some solvents |
| T4 | 135°C | Most common — covers petrol, diesel, most hydrocarbons |
| T5 | 100°C | Carbon disulfide applications |
| T6 | 85°C | Most demanding; diethyl ether, some esters |
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. T4 covers the majority of oil and gas and chemical plant applications. If your hazardous substance has an auto-ignition temperature below 135°C, you need T5 or T6 rated equipment — significantly fewer products are available at these ratings.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Reading ATEX Markings on Camera Equipment
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. ATEX markings contain all the information needed to verify compliance. Example: II 2G Ex d IIB T4 Gb
- II — Equipment Group II (surface industries; Group I is mines with firedamp)
- 2G — Category 2 (Zone 1 suitable), G = gas atmosphere
- Ex d — Flameproof protection concept
- IIB — Gas group (suitable for IIA and IIB gases; hydrogen/Group IIC requires IIC marking)
- T4 — Maximum surface temperature 135°C
- Gb — Equipment Protection Level for Zone 1 gas
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. To verify compliance: your zone classification document identifies the zone (0, 1, or 2) and the specific gas and group. Check that the camera’s ATEX marking shows a category appropriate for that zone (1G for Zone 0, 2G for Zone 1, 3G for Zone 2) and that the gas group and T-code cover your specific substance.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
ATEX vs. IECEx: What’s the Difference?
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. ATEX is a European Union directive (2014/34/EU) — it is a legal requirement for equipment placed on the market within the EU. IECEx is an international certification scheme managed by the International Electrotechnical Commission, accepted in over 50 countries across Asia-Pacific, Middle East, Africa, and South America. The technical standards underlying both schemes are harmonized (both reference IEC 60079 standards), but the certificates are not legally interchangeable without additional in-country acceptance.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. For North American installations, neither ATEX nor IECEx satisfies NEC requirements — a separate ATEX/IECEx or FM certification is needed. Many cameras available for international industrial use carry all three certifications (ATEX + IECEx + ATEX/IECEx), which simplifies procurement for facilities operating across multiple jurisdictions.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Practical Camera Selection by Zone
| Application Scenario | Zone | Minimum ATEX Certification Needed |
|---|---|---|
| Tank interior inspection camera (vapor space) | Zone 0 | II 1G Ex ia IIC T[x] Ga — intrinsically safe only |
| Refinery pump station external surveillance | Zone 1 | II 2G Ex d IIB T4 Gb (or higher) |
| Chemical plant process area cameras | Zone 1 (IIB gas) | II 2G Ex d IIB T4 Gb — IIB group required |
| Hydrogen electrolyzer room | Zone 1 (IIC gas) | II 2G Ex d IIC T4 Gb — IIC group required |
| Outdoor buffer zone around Zone 1 (no active venting) | Zone 2 | II 3G Ex nA IIA T4 Gc or better |
| Offshore platform open deck (near gas risers) | Zone 1 or 2 (per area drawing) | II 2G Ex d IIB T4 Gb + IP66 marine grade minimum |
Frequently Asked Questions
What is the difference between ATEX Zone 0, Zone 1, and Zone 2?
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Zone 0 is an area where a flammable atmosphere is present continuously or for long periods (e.g., inside a storage tank). Zone 1 is where it is likely to occur occasionally during normal operations (e.g., around venting equipment, pump seals). Zone 2 is where it is unlikely and occurs only under abnormal conditions, such as buffer zones around Zone 1 areas.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Can ATEX Zone 1 equipment be used in Zone 2?
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Yes. Equipment certified for a more hazardous zone is always acceptable in a less hazardous zone. Zone 1 certified cameras (Category 2G) can be used in Zone 2 areas. The reverse is not true — Zone 2 (Category 3G) equipment cannot be installed in Zone 1.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Is ATEX certification equivalent to ATEX/IECEx explosion-proof certification?
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. No. ATEX and ATEX/IECEx Certifications are not legally interchangeable. ATEX is required in the EU and many international markets. ATEX and IECEx certification is required in the USA and Canada for NEC-classified facilities. Equipment can hold both certifications, but one does not satisfy the requirement for the other.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
What temperature class (T-code) do I need for my ATEX camera?
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. The T-code must be below the auto-ignition temperature of the most hazardous substance present. T4 (135°C max surface temperature) covers most common hydrocarbons including petrol and diesel. T3 covers heavier oils. If hydrogen (IIC) is present, T1 (450°C) is sufficient thermally, but the IIC group rating is the critical factor. Always verify against your area classification document.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
What does the ATEX marking ‘II 2G Ex d IIB T4 Gb’ mean?
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Breaking down the marking: ‘II’ = surface industries equipment group; ‘2G’ = Category 2 suitable for Zone 1, gas atmosphere; ‘Ex d’ = flameproof protection concept; ‘IIB’ = gas group (covers up to ethylene; hydrogen requires IIC); ‘T4’ = maximum surface temperature 135°C; ‘Gb’ = Equipment Protection Level for Zone 1 gas.
For definitions of key hazardous area terms used in this guide, see the Hazardous Area Classification Glossary.
Further Resources
Selecting the right ATEX Zone 1 or Zone 2 camera starts with understanding what each zone classification means and which protection concepts are permitted in each. Browse Veilux’s range of explosion-proof cameras and explosion-proof housings certified for hazardous areas. For regulatory reference, see IECEx certification body and UK HSE ATEX guidance.
For a complete overview of all selection criteria, see the Explosion-Proof Camera Selection Guide: Complete Hub.
Related Articles
- NEC vs ATEX: The Global Compliance Crosswalk
- Class 1 Division 1 vs Division 2 Guide
- Intrinsically Safe vs Explosion-Proof Cameras
- Offshore Explosion-Proof Cameras: ATEX Requirements
Ready to Specify Certified Explosion-Proof Equipment?
Veilux provides ATEX/IECEx certified, ATEX-certified, and IECEx-approved explosion-proof cameras, housings, and lighting for hazardous industrial locations. Submit your zone classification, application details, and coverage requirements for a technical quote.
Key Takeaways: Atex Zone 0 Zone 1 Zone 2 Camera
Atex Zone 0 Zone 1 Zone 2 Camera is essential equipment in hazardous classified environments where flammable gases, vapors, or dust may be present. Facilities relying on Atex Zone 0 Zone 1 Zone 2 Camera benefit from enhanced safety and regulatory compliance with ATEX, IECEx, and ATEX/IECEx Certifications. When specifying Atex Zone 0 Zone 1 Zone 2 Camera for your site, match the certification to your area classification — Zone 0/1/2 or Class I Division 1/2. Atex Zone 0 Zone 1 Zone 2 Camera from Veilux is available in fixed and PTZ configurations to suit perimeter, process, and critical-area coverage needs. Properly maintained Atex Zone 0 Zone 1 Zone 2 Camera extends system life and upholds certification validity per NFPA 70E inspection requirements.
For the North American NEC equivalent, see our Class I vs. Class II vs. Class III hazardous locations guide covering all division ratings.
About the Author
Daniel Fernandez
Daniel Fernandez is a hazardous area security systems specialist with over a decade of experience specifying ATEX, IECEx, UL Class I Division 1, and cUL certified surveillance equipment for oil and gas, chemical, mining, pharmaceutical, and offshore environments. He holds expertise in NEC and IEC area classification standards and has consulted on explosion-proof camera system designs across North America, Europe, and the Middle East.