Marking of pressure sensors and transmitters according to ATEX Guideline 94/9/EC ? how to browse the ATEX label on pressure sensors

If pressure sensors, pressure transmitters and other field equipment are employed in the vicinity of flammable gases or dust, they may be subject to marking relative to the ATEX product guideline 94/9/EC. ATEX requires the sort label of the sensor to include the ATEX marking, so usually that is labelled directly onto the sensor during production.
Next to the Notified Body and the approval number, the marking of pressure sensors also includes important information for an individual. For instance, an ?X? after the approval number indicates that special conditions should be observed when using the device. These are either given in the approval document and in the corresponding manual. Above all, marking in accordance with ATEX gives information on the possible areas of application and the sort of protection used for the pressure sensor:
Explosion group:
I Mining industry, II the areas useful Device class:
Use in zone 0/20 near von flammable gases (1G), dust (1D)
Used in zone 1/21 near flammable gases (2G), dust (2D)
Used in zone 2/22 near flammable gases (3G), dust (3D)
However, there are also devices where only certain parts may be installed in other zones, for example, a pressure sensor marked 1/2G could be installed in a tank with flammable content. Immediately of the transmitter is located externally of the tank, and therefore in zone 1.
Examples for forms of protection:
i intrinsic safety (Limitation of electrical ignition energy by limiting current and voltage)
ia for Zone 0 or Zone 20 (for Zone 20 also iaD)
ib for Zone 1 or Zone 21 (for Zone 21 also ibD)
ic for Zone 2 d
flameproof / explosion proof enclosure, suitable for zone 1/21 and 2/22 n
non-incendive, suitable for zone 2/22 m
encapsulation ideal for zone 1/21 and 2/22 Gas group and temperature class: i.e. IIC T1 for hydrogen
Note:
Further information on the subject of hydrogen are available on the WIKA website. In case you have any more questions, your contact will gladly help you.

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