If pressure sensors, pressure transmitters along with other field equipment are employed near flammable gases or dust, they might be subject to marking relative to the ATEX product guideline 94/9/EC. ATEX 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 includes important information for the user. For instance, an ?X? following the approval number indicates that special conditions must 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 home elevators the possible regions 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)
Use in zone 2/22 in the vicinity of flammable gases (3G), dust (3D)
However, additionally, there are devices where only certain parts could be installed in other zones, for instance, a pressure sensor marked 1/2G may be installed in a tank with flammable content. เพชเชอร์เกจ 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, 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. In case you have any further questions, your contact will gladly assist you to.