---
title: "ATEX directive (2014/34/EU)"
description: "The ATEX directive (2014/34/EU) sets European Union requirements for equipment and protective systems used in atmospheres containing potentially explosive concentrations of gas, vapour, mist or dust. ATEX certification is mandatory in the EU for industrial equipment installed in classified hazardous areas, including most sonic-horn installations on coal, biomass, WtE, cement, mining, fertilizer and food applications."
canonical_url: "https://sylio.co/glossary/atex-directive"
last_updated: "2026-06-28T02:29:38.119Z"
---

The **ATEX directive (2014/34/EU)** sets European Union requirements for equipment and protective systems used in atmospheres containing potentially explosive concentrations of gas, vapour, mist or dust. ATEX certification is mandatory in the EU for industrial equipment installed in classified hazardous areas, including most [sonic-horn](/glossary/sonic-horn) installations on coal, biomass, [WtE](/glossary/waste-to-energy), cement, mining, fertilizer and food applications.

## ATEX zones

The directive classifies hazardous areas by the likelihood and persistence of an explosive atmosphere:

<table>
<thead>
  <tr>
    <th>
      Zone
    </th>
    
    <th>
      Atmosphere type
    </th>
    
    <th>
      Frequency / duration
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      <strong>
        Zone 0
      </strong>
    </td>
    
    <td>
      Gas / vapour / mist
    </td>
    
    <td>
      Present continuously or for long periods
    </td>
  </tr>
  
  <tr>
    <td>
      <strong>
        Zone 1
      </strong>
    </td>
    
    <td>
      Gas / vapour / mist
    </td>
    
    <td>
      Likely to occur in normal operation
    </td>
  </tr>
  
  <tr>
    <td>
      <strong>
        Zone 2
      </strong>
    </td>
    
    <td>
      Gas / vapour / mist
    </td>
    
    <td>
      Not likely in normal operation; brief if present
    </td>
  </tr>
  
  <tr>
    <td>
      <strong>
        Zone 20
      </strong>
    </td>
    
    <td>
      Combustible dust cloud
    </td>
    
    <td>
      Present continuously or for long periods
    </td>
  </tr>
  
  <tr>
    <td>
      <strong>
        Zone 21
      </strong>
    </td>
    
    <td>
      Combustible dust cloud
    </td>
    
    <td>
      Likely to occur in normal operation
    </td>
  </tr>
  
  <tr>
    <td>
      <strong>
        Zone 22
      </strong>
    </td>
    
    <td>
      Combustible dust cloud
    </td>
    
    <td>
      Not likely in normal operation; brief if present
    </td>
  </tr>
</tbody>
</table>

Industrial sonic horns are most often certified for **Zone 21 or Zone 22** dust service — appropriate for [coal bunkers](/glossary/bunker-coal-bunker), [fly-ash hoppers](/glossary/fly-ash-hopper), [biomass silos](/glossary/silo), [cement preheater cyclones](/glossary/preheater-cyclone), [recovery boilers](/glossary/recovery-boiler) and similar duty.

## Why pneumatic horns suit ATEX so well

[Pneumatic acoustic cleaners](/glossary/pneumatic-acoustic-cleaner) place no electrical parts inside the dust-laden gas volume. The only ignition consideration is mechanical sparking, which is engineered out by suitable material selection. This is one of the structural reasons sonic horns are the preferred flow-aid technology for combustible-dust environments.

## Equivalent international standards

- [IECEx](/glossary/iecex) — globally accepted equivalent scheme
- [Class I Div 1 / Div 2 (NEC)](/glossary/class-i-div-1-div-2-nec) — US National Electrical Code
- [IEC 60079](/glossary/iec-60079) — underlying technical standard

## Related terms

- [IECEx](/glossary/iecex)
- [IEC 60079](/glossary/iec-60079)
- [Class I Div 1 / Div 2 (NEC)](/glossary/class-i-div-1-div-2-nec)
- [CE marking](/glossary/ce-marking)
- [Pneumatic acoustic cleaner](/glossary/pneumatic-acoustic-cleaner)