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

If pressure sensors, pressure transmitters along with other field equipment are used near flammable gases or dust, they may be subject to marking in accordance with the ATEX product guideline 94/9/EC. Certain requires the type label of the sensor to include the ATEX marking, so usually this is labelled directly onto the sensor during production.
Close to the Notified Body and the approval number, the marking of pressure sensors also contains important information for the user. For instance, an ?X? following the approval number indicates that special conditions should be observed with all the device. They are either given in the approval document and in the corresponding manual. Above all, marking according to ATEX gives info on the possible regions of application and the sort of protection useful for the pressure sensor:
Explosion group:
I Mining industry, II other areas of use Device class:
Use in zone 0/20 in the vicinity of von flammable gases (1G), dust (1D)
Used in zone 1/21 in the vicinity of flammable gases (2G), dust (2D)
Use in zone 2/22 near flammable gases (3G), dust (3D)
However, additionally, there are devices where only certain parts could be installed in other zones, for example, a pressure sensor marked 1/2G could be installed in a tank with flammable content. Crazy of the transmitter is located on the outside of the tank, and thus in zone 1.
Examples for types 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, ideal for zone 1/21 and 2/22 n
non-incendive, ideal 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 about hydrogen can be found on the WIKA website. When you have any further questions, your contact will gladly assist you to.

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