How to Read an Exproof Fan Label: ATEX Marking Guide
The letters and numbers on an exproof fan label may look complex at first. When the marking is read correctly, however, it quickly provides critical information about the hazardous-area conditions for which the equipment has been designed.
What information should you look for on the label?
Depending on the product and certificate structure, ATEX/Ex marking can include the equipment group and category, gas or dust atmosphere, Ex protection concept, gas/dust group, temperature class or maximum surface temperature, and EPL.
The manufacturer name, model, serial number, certificate number, production information and permitted ambient-temperature range should also be checked. Some certificates contain special conditions of use, so suffixes on the certificate number or notes in the technical documentation may be important.
In practice, the goal is not to memorise every character on the label. The useful question is: do the documented conditions of use for this product match the zone, gas/dust group and temperature requirement at my site?
How can an example marking be decoded?
For example, a marking such as II 2G Ex db IIB T4 Gb can be read in parts:
- II: equipment group for non-mining industrial use
- 2G: equipment category for a gas atmosphere
- Ex db: the relevant explosion-protection concept / protection-level marking
- IIB: gas group
- T4: maximum surface-temperature class
- Gb: equipment protection level (EPL)
This example is intended to explain the logic of the marking. A real fan label may include different protection concepts, ambient-temperature information or additional symbols. An order decision should always be based on the actual product label and certificate.
How should the label be compared with the zone?
For a site classified as Zone 1, the first check is whether the equipment has a category/EPL suitable for that zone. The review does not stop there. Gas group, temperature class, protection concept, ambient temperature and any special certificate conditions must also be compared with the site requirements.
For example, a product that appears suitable for Zone 1 by category/EPL but is certified only for gas group IIA cannot be used where IIC is required. Likewise, equipment marked T3 does not satisfy an application requiring T4.
Label verification is therefore not a one-box exercise. Several parameters must be suitable at the same time.
Is checking only the motor label enough?
No. Even if the motor on an exproof fan is certified, the impeller, casing, connections, mechanical clearances and possible rubbing or sparking risks must also be evaluated. The fan performance characteristic is also part of a safe and functional selection.
During purchasing, the declaration of conformity for the complete fan, the product nameplate and relevant technical documentation should be reviewed. Whether the motor certificate represents the complete fan must be verified from manufacturer documentation rather than assumed.
The same principle applies during maintenance and part replacement. An unsuitable change to a component that affects the certified construction can invalidate the basis on which the original selection was made.
Pre-order checklist
A short pre-order checklist can significantly reduce the risk of an incorrect selection:
- Has the zone and gas/dust classification been defined correctly?
- Does the category/EPL match the site?
- Is the gas or dust group suitable?
- Is the temperature class / maximum surface temperature sufficient?
- Is ambient temperature within the certificate limits?
- Have the protection concept and any special certificate conditions been checked?
- Does the fan meet the required airflow and pressure?
If any of these points is unclear, it should be resolved with the project team or manufacturer before the selection is finalised. The next step is to use these inputs together and select the exproof fan systematically.