ATEX fans are typically used within chemical, petrochemical and process industries with many flameproof fan enquiries coming from specifiers, resellers and end-users, some of whom may not be aware of ATEX Directives.
ATEX is an acronym derived from the French expression ATmosphères EXplosibles and exists in the form of two European directives for controlling explosive atmospheres. The first ‘equipment directive’ 94/9/EC (ATEX 100) covers manufacturing standards. The second ‘workplace directive’ ATEX 99/92/EC (ATEX 137) seeks to ensure that people are protected against the risk of blast injuries or asphyxiation by dangerous substances. The 2016 updated legislation is Directive 2014/34/EU and assists with establishing a uniformity to the approach taken when supplying and distributing equipment such as industrial fans for explosive atmospheres.
Everyone involved in the specification, manufacture, installation, and use of equipment in flameproof zones has some responsibility and a duty of care to ensure that the law concerning flameproof equipment is upheld.
Unfortunately, a lack of practice with the subject tends to give rise to enquiries that begin with statements like “there is a slight risk of explosion, but we don’t think we need a flameproof fan” which places manufacturers in an awkward position because they are not ATEX consultants and are not qualified to know what the client can lawfully install.
What can the fan supplier do with casual enquiries that must at some point turn into tightly specified orders? The first option is a blunt “come back when you know exactly what is required” and the second is to issue a questionnaire, usually with ‘tick boxes” and a bit of guidance appended, which may then be returned with conflicting selections.
What is needed in every case is an ATEX code that provides a well-defined minimum standard for the product that is required. For example, the code Ex II 2G IIC T4 essentially means European flameproof, surface industry (not mining), Category 2 (Zone 1), gas group II, type C (hydrogen or acetylene gas), maximum surface temperature 135º°C
There are many other coding permutations including slightly different formats for dusty atmospheres (Zones 21 & 22). If codes cannot be provided there is lingering uncertainty over what is required.
Once an ATEX code has been established by the end-user the process of selecting a fan model and its essential features demands a degree of application knowledge.
For example, the type of electrical supply is important. Single phase is an expensive option and not widely available from ATEX motor manufacturers. It may be cheaper to run a 3~ line than to buy a 1~ fan on a long manufacturing lead-time.
Any fan motor that is to be speed controlled with a VSD must also have thermistors fitted to protect against motor shell temperature at low speeds causing spontaneous gas combustion. By not mentioning the VSD aspect at the enquiry or order stage the purchaser is likely to ultimately face time and product replacement costs.
Other matters include motors that vary from the most secure specification EEx d (explosion proof) through EEx e (increased safety), down to EEx nA (non-sparking) which has many similarities to a standard non-flameproof motor.
ATEX has to be understood as being an ever-evolving subject requiring competence and training that is now provided by several UK Notified Bodies and consultancies. Anyone requiring a better understanding of flameproof requirements would be advised to contact them for further information.
Axair Fans UK Ltd
Lowfield Drive
Wolstanton
Newcastle-Under-Lyme
ST5 0UU
England
01782 349439
