EDITOR ’ S CHOICE ATEX FANS
AXAIR
An Explosive Issue
Outside of major users such as chemical , petrochemical and process industries , enquiries for flameproof fans tend to come from specifiers , resellers and end-users , many 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 in ensuring that the law concerning flameproof equipment is upheld .
This article highlights some of the issues affecting manufacturers and distributors of ATEX fans .
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
ATEX must be understood as being an ever-evolving subject requiring competence and training .
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 135 º° 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 . Often the response to “ what electrical supply do you have ” is “ can be single or three phase ”. 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 ( nonsparking ) which has many similarities to a standard non-flameproof motor .
ATEX must be understood as being an ever-evolving subject requiring competence and training . Anyone requiring a better understanding of flameproof requirements would be advised to seek further information .
For further information , please visit www . axair-fans . co . uk
22 PECM Issue 55