Zone 2 / Div 2 covers most industrial areas
Most oil and gas, chemical, and mining applications require Zone 2 or Division 2 certification. Zone 0 and Zone 1 require intrinsically safe equipment with much lower power limits.
21.3 Hazardous Location Networks
Substations operate in controlled environments. Oil refineries, chemical plants, grain silos, and mines contain explosive atmospheres where a spark from electrical equipment can cause an explosion. This section covers the certification frameworks and Hirschmann products for hazardous location networks.
Hazardous Location Frameworks
Section titled “Hazardous Location Frameworks”Three major certification frameworks govern electrical equipment in explosive atmospheres:
| Framework | Region | Zone/Division |
|---|---|---|
| ATEX (EU Directive 2014/34/EU) | European Union | Zone 0, 1, 2 (gas); Zone 20, 21, 22 (dust) |
| IECEx (IEC 60079 series) | International | Zone 0, 1, 2 (gas); Zone 20, 21, 22 (dust) |
| ISA12.12.01 / FM3611 | North America | Class 1 Division 1, Division 2 |
| NEC Article 500 | North America | Class 1 Division 1, Division 2 |
Key terms:
- ATEX — the EU directive for equipment used in explosive atmospheres; “ATEX” comes from the French “ATmosphères EXplosibles”
- IECEx — the international certification scheme for equipment used in explosive atmospheres; based on IEC 60079 standards
- Zone 2 / Class 1 Division 2 — an area where an explosive atmosphere is not likely to occur in normal operation, but may occur in abnormal conditions; the most common classification for industrial networking equipment
- Intrinsic safety — a protection method that limits electrical energy to levels below what can ignite an explosive atmosphere
Zone 2 vs Division 2
Section titled “Zone 2 vs Division 2”Zone 2 (ATEX/IECEx) and Class 1 Division 2 (North American) are roughly equivalent:
| Classification | Description | Typical Locations |
|---|---|---|
| Zone 0 / Div 1 | Explosive atmosphere present continuously | Inside storage tanks |
| Zone 1 / Div 1 | Explosive atmosphere likely in normal operation | Near tank vents |
| Zone 2 / Div 2 | Explosive atmosphere unlikely in normal operation | General refinery areas |
Most industrial networking equipment is certified for Zone 2 / Division 2. Zone 0 and Zone 1 require intrinsically safe equipment, which has much lower power limits.
Protection Methods
Section titled “Protection Methods”| Method | Symbol | Description |
|---|---|---|
| Flameproof enclosure | Ex d | Enclosure withstands internal explosion |
| Increased safety | Ex e | Prevents sparks and hot surfaces |
| Intrinsic safety | Ex i | Limits energy to safe levels |
| Non-sparking | Ex n | Prevents sparks in normal operation |
| Purged/pressurized | Ex p | Positive pressure prevents gas ingress |
Most Hirschmann switches for Zone 2 use the non-sparking (Ex n) protection method. The switch is designed so that it cannot produce sparks or hot surfaces that could ignite an explosive atmosphere under normal operation.
Hirschmann Products for Hazardous Locations
Section titled “Hirschmann Products for Hazardous Locations”| Product | Certification | Notes |
|---|---|---|
| SPIDER III (variants) | IECEx Zone 2, ATEX Zone 2 | Unmanaged, DIN rail |
| RSPE (variants) | ATEX Zone 2, ISA12.12.01 | Full managed, DIN rail |
| GREYHOUND (variants) | ISA12.12.01 Class 1 Div 2 | Rack mount |
| EAGLE One (variants) | ISA12.12.01 Class 1 Div 2, ATEX Zone 2 | Firewall |
Key Takeaways
Section titled “Key Takeaways”Check the order code for approval suffix
Hazardous location approvals are variant-specific. Verify the order code includes the correct approval suffix before ordering.
What Comes Next
Section titled “What Comes Next”With market-specific requirements covered, the final section provides a comprehensive product selection guide — a single reference for choosing the right Hirschmann product for any application.
References
Section titled “References”- IEC 60079-0:2017 — Explosive atmospheres — General requirements
- ATEX Directive 2014/34/EU — Equipment and protective systems intended for use in potentially explosive atmospheres
- ISA12.12.01-2013 — Nonincendive Electrical Equipment for Use in Class I and II, Division 2 and Class III, Divisions 1 and 2 Hazardous (Classified) Locations
- Hirschmann. (2024). Belden/Hirschmann Essentials 2024. Belden.