The ATEX directive, if you are not familiar, is the EU directives that describe what equipment and work environment is allowed in the presence of an explosive atmosphere.  The ATEX equipment directive 94/9/EC covers equipment intended for use in potentially explosive atmospheres.

For ignition to occur, there must be three things present.  First a sufficient amount of flammable or combustible substance.  Secondly, air or oxygen, the fuel that allows things to burn.  Third, an ignition source.  The ignition source is typically a spark or a hot enough surface for conditions.

The directive provides a classification based on the equipment group and the equipment category.  Equipment Groups are divided into two - group I, which are mines and group II, which are above ground.  Equipment Categories further describes the equipment protection with  atmospheric conditions and protection level. There are five equipment categories - M1- Methane & Dust, Very High Protection, M2 - Methane & Dust, High Protection, 1 - Gas, Vapor, Mist, Dust, Very High Protection, 2 - Gas, Vapor, Mist, Dust, High Protection, 3 - Gas, Vapor, Mist, Dust, Low Protection.

Each Equipment Group/Equipment Category is acceptable for for a certain Zone classification.  Zone 0 is an area with an explosive atmosphere of gas, vapor or mist present continuously, for long periods, or frequently.  Zone 1 is an area with an explosive atmosphere of gas, vapor or mist present occasionally.  Zone 2 an an area with an explosive atmosphere of gas, vapor or mist not likely to occur or for a short duration.

The zones expanded further to describe areas with combustible dust.  Zone 20 is an area with a cloud of combustible dust is present continuously, for long periods, or frequently.  Zone 21 is an area with a cloud of combustible dust is present occasionally.   Zone 22 is an area with a cloud of combustible dust not likely to occur or for a short duration.

Each Zone, therefore,  has an associated equipment category that is suitable for operation in that particular Zone as follows-

By defining the Equipment Group and the Equipment Category, we know what Zone the device will be suitable for. For example, a machine approved Equipment Group I Category 2 is suitable for mines and has high protection against explosion, thus  would be acceptable for Zone 21.

All Apex Dynamics gearboxes are rated Equipment Group II Category 2.  The Declaration of Conformity can be downloaded here or from our website on the press page.

Of course, a gearbox by itself has no potential to create a source of ignition.  We have to use our heads, let common sense prevail and make decisions on the evidence we have.  Each application is different and operating parameters can change what equipment group the completed machine will fall in.

For any questions, contact our sales and applications team at 631-244-9040 or sales@apexdynamicsusa.com or click on the Contact Us link at the top of the page.