ATEX Directive 2014/34/EU: Hazardous Zones 0/1/2 & 20/21/22, Equipment Categories and EN 60079-17 Inspections
How do ATEX explosive zones correspond to equipment categories, and what inspections are required under EN 60079-17? Under EU ATEX Workplace Directive 1999/92/EC and Equipment Directive 2014/34/EU, hazardous areas are classified into Zones 0, 1, and 2 for flammable gases/vapors, and Zones 20, 21, and 22 for combustible dusts. Equipment installed in Zone 0/20 must belong to Category 1G/1D (very high protection, safe under two independent faults); Zone 1/21 requires Category 2G/2D (high protection, safe under single fault); Zone 2/22 requires Category 3G/3D (normal protection). Under standard EN 60079-17, industrial plants must conduct recurring inspections across three grades: Visual, Close, and Detailed, with an inspection interval not exceeding 3 years for electrical installations.
Complete guide to ATEX zoning, equipment categories (1G/1D, 2G/2D, 3G/3D), temperature classes, and EN 60079-17 recurring inspection routines.
Technical Specifications & Regulatory Comparison Matrix
| Hazardous Zone | Atmosphere Type | Presence of Explosive Atmosphere | Mandatory Equipment Category | Protection Concepts |
|---|---|---|---|---|
| Zone 0 | Gas, vapor, mist | Continuous or long periods (>1000 hrs/yr) | Category 1G | |
| Zone 1 | Gas, vapor, mist | Occasional in normal operation (10-1000 hrs/yr) | Category 2G | |
| Zone 2 | Gas, vapor, mist | Unlikely & short duration (<10 hrs/yr) | Category 3G | |
| Zone 20 | Combustible dust cloud | Continuous or long periods (>1000 hrs/yr) | Category 1D | |
| Zone 21 | Combustible dust cloud | Occasional in normal operation (10-1000 hrs/yr) | Category 2D | |
| Zone 22 | Combustible dust layer/cloud | Unlikely & short duration (<10 hrs/yr) | Category 3D |
1. Reading an ATEX Equipment Rating Plate
Engineers must verify the complete marking string (e.g., CE 0081 Ex II 2G Ex db IIC T4 Gb). The code indicates: 0081 (Notified Body ID for production surveillance), II (surface industry equipment), 2G (Zone 1 gas category), Ex db (flameproof enclosure), IIC (hydrogen/acetylene gas group), T4 (max surface temp 135°C), and Gb (Equipment Protection Level - EPL).