If pressure sensors, pressure transmitters and 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. Wanted requires the sort label of the sensor to add the ATEX marking, so usually that 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. These are either given in the approval document and in the corresponding manual. Most importantly, marking in accordance with ATEX gives home elevators the possible regions of application and the type of protection useful for the pressure sensor:
Explosion group:
I Mining industry, II other areas of use Device class:
Use in zone 0/20 near 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 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 example, a pressure sensor marked 1/2G may be installed in a tank with flammable content. The electronic the main transmitter is located on the outside 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, suitable 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 about hydrogen are available on the WIKA website. Should you have any more questions, your contact will gladly help you.