If pressure sensors, pressure transmitters and other field equipment are used near flammable gases or dust, they may be subject to marking relative to the ATEX product guideline 94/9/EC. Verify requires the type 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 an individual. For example, an ?X? after 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. Above all, marking according to 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 useful Device class:
Used in zone 0/20 near von flammable gases (1G), dust (1D)
Use 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, there are also devices where only certain parts may be installed in other zones, for instance, a pressure sensor marked 1/2G could be installed in a tank with flammable content. The electronic area of the transmitter is located on the outside of the tank, and thus 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, ideal for zone 2/22 m
encapsulation suitable for zone 1/21 and 2/22 Gas group and temperature class: i.e. Exposed for hydrogen
Note:
Further information about hydrogen are available on the WIKA website. For Pay Zero who have any more questions, your contact will gladly help you.g