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 and other field equipment are employed near flammable gases or dust, they might be subject to marking in accordance with the ATEX product guideline 94/9/EC. pressure gauge 2.5 นิ้ว requires the type label of the sensor to add 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 must be observed with all the device. These are either given in the approval document and in the corresponding manual. Most importantly, marking in accordance with ATEX gives information 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)
Use in zone 1/21 in the vicinity of flammable gases (2G), dust (2D)
Used in zone 2/22 in the vicinity of flammable gases (3G), dust (3D)
However, there are also devices where only certain parts may be installed in other zones, for instance, a pressure sensor marked 1/2G may be installed in a tank with flammable content. The electronic area of the transmitter is located on the outside 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, ideal 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 about hydrogen are available on the WIKA website. When you have any further questions, your contact will gladly help you.

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