If pressure sensors, pressure transmitters and 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. ATEX requires the type label of the sensor to include 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 example, an ?X? after the approval number indicates that special conditions should be observed when using the device. Miracle are either given in the approval document and in the corresponding manual. Most importantly, marking in accordance with 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 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 may 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 externally 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, suitable 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 on the subject of hydrogen are available on the WIKA website. In case you have any more questions, your contact will gladly assist you to.