# What Is ATEX and Ex Classification in Hazardous Areas?

**URL:** <https://forumautomation.com/t/what-is-atex-and-ex-classification-in-hazardous-areas/14579>\
**Category:** Industrial Automation\
**Created:** [November 6, 2026, 6:11am UTC](https://forumautomation.com/t/what-is-atex-and-ex-classification-in-hazardous-areas/14579 "2026-11-06T06:11:48Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Sundar\_Iyalunaidu](https://forumautomation.com/user_avatar/forumautomation.com/sundar_iyalunaidu/32/7404_2.png) [@Sundar\_Iyalunaidu](https://forumautomation.com/u/Sundar_Iyalunaidu)\
**Post date:** [November 6, 2026, 6:11am UTC](https://forumautomation.com/t/what-is-atex-and-ex-classification-in-hazardous-areas/14579/1 "2026-11-06T06:11:48Z")

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Continuing the discussion from [What is ATEX and EX classification?](https://forumautomation.com/t/what-is-atex-and-ex-classification/14561):

# **What Is ATEX and Ex Classification in Hazardous Areas?**

ATEX is the European regulatory framework for industrial equipment used in potentially explosive atmospheres. “Ex” identifies equipment designed with explosion protection. They are related, but not interchangeable: ATEX addresses legal conformity for applicable European markets, while Ex markings describe protection and equipment suitability.

### **Hazardous area classification**

Gas and vapour areas are classified as Zone 0, 1 or 2. Zone 0 has an explosive atmosphere continuously, frequently or for long periods; Zone 1 may experience it occasionally during normal operation; Zone 2 is unlikely during normal operation and, if present, lasts briefly. Combustible dust uses Zones 20, 21 and 22.

### **Equipment selection**

For surface industries, ATEX Group II categories correspond as follows: Category 1G: Zone 0; Category 2G: Zone 1; Category 3G: Zone 2. Category 1D: Zone 20; Category 2D: Zone 21; Category 3D: Zone 22.

The marking also identifies gas or dust group, temperature class and protection method. IIC covers demanding gas groups such as hydrogen, while T4 limits equipment surface temperature to 135°C. Check the certificate and ambient-temperature limits.

### **Plant engineering example**

When specifying a pressure transmitter near a hydrocarbon pump, confirm the area-classification drawing, gas group, temperature class, zone, protection concept and installation conditions. An Ex certificate alone does not prove suitability for every hazardous location.

### **Practical takeaway**

Verify equipment against the project hazardous-area dossier and applicable standards before purchase, installation or maintenance. Never select an instrument using the Ex symbol alone; its complete marking and certificate must match the classified area.