Marking of pressure sensors and transmitters in accordance with ATEX Guideline 94/9/EC ? how exactly to read 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 might be subject to marking in accordance with the ATEX product guideline 94/9/EC. ATEX requires the sort label of the sensor to include the ATEX marking, so usually this 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 the user. For Vibrant , an ?X? after the approval number indicates that special conditions must be observed when using the device. These are either given in the approval document and in the corresponding manual. Above all, marking according to ATEX gives info on the possible areas of application and the type of protection used for the pressure sensor:
Explosion group:
I Mining industry, II other areas useful Device class:
Used in zone 0/20 in the vicinity of von flammable gases (1G), dust (1D)
Used in zone 1/21 near flammable gases (2G), dust (2D)
Use 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. The electronic area of the transmitter is located externally of the tank, and therefore 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 suitable 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. When you have any more questions, your contact will gladly help you.

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