Mechanical Equipment of ATEX Atmosphere
The mechanical equipment and protection systems, that are entering the markets the first time, must fill the safety requirements for mechanical devices used in ATEX-atmosphere. The responsibility of fulfilling the requirements is on the designers and manufacturers.
The name ATEX is used for the European Commission directive 94/9/EC (2014/34/EU from 20.4.2016) which applies to all equipment and machines for explosive spaces, which enter the market after July 30th, 2003. The initiative of the directive is to unify the safety requirements of explosive atmosphere throughout the European Commission states and therefore guarantee the free trading of Ex-devices.
The standard series SFS-EN 13463 is an important standard together with ATEX directive. The standard covers the explosion protection implementation of the mechanical equipment (other than electrical equipment) from the designing and structuring perspective.
EN 13463 series include different explosion protection structures for mechanical equipment and the part 1 introduces the principles of how to use different protection structures and gain a certain level of protection. The standard SFS-EN 13463-1 is equivalent to basic standard of electronics, EN 60079-0. When complying with good manufacturing practise, SFS-EN 13463-1 is by itself adequate to reach the device category 3 in group II in ATEX directive.
The main principles
The standard SFS-EN 13463-1 requires that a special evaluation of the flammability of a sketched mechanical equipment must be done (and documented) and according to the results the ATEX directive classification can be determined and proved.
When must the flammability be assessed?
Flammability must be reported always when the equipment is designed to be used in conditions or spaces where the air mix is explosive. The new ATEX device directive 2014/34/EU requires the equipment manufacturer to have more adequate and clearer flammability assessing than before.
All possible sources of ignition are recognized and listed and the applicable actions, that prevent them turning to active sources of ignition, are recognized.
Potential sources of ignition
- Open fire
- Hot fumes or liquids
- Mechanically flammable sparks
- Adiabatic compression
- Pressure surge
- Heat producing chemical reactions
- Termite reactions
- Self-ignition of dust
- Light arcs
- Static electricity
Designing and/or protecting the equipment so that they do not have sources of ignition.
Required protection level in different classes
Cole mining devices – Group I
Device group M1
Very high protection level. The equipment can operate in an explosive mixture.
Device group M2
High protection level. The equipment are switch off when an explosive mixture occurs.
Industrial devices – Group II
Device group 1
Very high protection level. The equipment are designed to spaces, where an explosive mixture occurs constantly or long periods (classes 0 and 20).
Device group 2
High protection level. The equipment are meant for spaces where an explosive mixture is likely to occur in normal use (classes 1 and 21).
Device group 3
Normal safety level. The equipment are meant for spaces, where an explosive mixture is not likely appearing and if so, only rarely and temporarily (classes 2 and 22).