Home > Selecting an ATEX fan: a step-by-step guide

Selecting an ATEX fan: a step-by-step guide

Selecting the right ATEX fan for a hazardous area starts with the environment, not the product. Before any fan can be specified, the explosive atmosphere must be properly classified according to the ATEX directive (2014/34/EU). This step-by-step guide covers every decision required to arrive at a correct and compliant specification for a fan intended for use in a potentially explosive atmosphere. If there is any uncertainty about any of the steps, consulting a certified ATEX specialist is strongly advisable. The consequences of an incorrect specification can be severe.

Step 1: Identify the ATEX zone

What is the zone classification of the location where the fan will be installed? Is there an official zoning plan, documented in an Explosion Protection Document (EPD)? If not, have one drawn up by a certified ATEX specialist before proceeding. Without an established zone classification, a correct fan specification for a hazardous area is not possible.

Want to learn more zone classification? Read our article on ATEX zones.

Step 2: Establish the required equipment category

The zone classification directly determines the minimum required equipment category under the ATEX directive:

Zone 0 / 20 → Category 1
Zone 1 / 21 → Category 2
Zone 2 / 22 → Category 3

Also establish whether the atmosphere involves gas or dust: G for gas, D for dust. This determines the equipment group marking on the fan.

Step 3: Verify the required T-class

Which flammable substances are present in the hazardous area? The auto-ignition temperature of those substances can be found in the relevant safety data sheet or in an ATEX gas database. The maximum surface temperature of the fan — as defined by its T-class — must remain sufficiently below that value under all operating conditions. Take into account the required margins for your specific application.

Step 4: Determine the gas group (for gas zones)

Which flammable gas or vapour is present? The gas group is one of the factors that determines which ATEX-certified fan is suitable for the application:

Group IIA: including methane, propane and ethanol
Group IIB: including ethylene and certain solvents
Group IIC: including hydrogen and acetylene (most stringent requirement)

A fan certified for Group IIC is also suitable for IIA and IIB environments. Select the group that corresponds to the substances present in your installation.

Step 5: Select the fan type and air performance

Only once the zone, category, T-class and gas group have been established does the actual fan specification come into play. Consider: which fan type (axial, centrifugal or jet fan), what flow rate (m³/h), what static pressure, what construction material (particularly relevant in corrosive environments), and what motor power is required. Verify that the desired fan type is available in the correct ATEX configuration — certified to EN 14986:2017 — for the established parameters.

Step 6: Verify the documentation

Request the relevant conformity documentation from your supplier. For ATEX equipment this includes the EU declaration of conformity and — depending on the equipment category and type — any certificates issued by a notified body. Keep these documents as part of your Explosion Protection Document (EPD), as required under the ATEX workplace directive (1999/92/EC).

When in doubt: consult a specialist

If there is any uncertainty about the zone classification, T-class, gas group or the correct equipment category, consulting an independent ATEX specialist is strongly advisable. The consequences of an incorrect specification for explosion-proof ventilation can be severe.

Ventinet ATEX fans

We supply ATEX-certified fans for virtually every application. For questions about available configurations or to discuss which fan suits your situation, feel free to contact us or browse our ATEX fan range directly.