If pressure sensors, pressure transmitters and other field equipment are employed near flammable gases or dust, they may be subject to marking relative to the ATEX product guideline 94/9/EC. ATEX requires the type label of the sensor to add 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 Confession , 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. Most importantly, marking in accordance with ATEX gives home elevators the possible areas of application and the type of protection useful for the pressure sensor:
Explosion group:
I Mining industry, II the areas useful Device class:
Use in zone 0/20 in the vicinity of von flammable gases (1G), dust (1D)
Use in zone 1/21 near flammable gases (2G), dust (2D)
Used in zone 2/22 near flammable gases (3G), dust (3D)
However, there are also devices where only certain parts could be installed in other zones, for example, a pressure sensor marked 1/2G could be installed in a tank with flammable content. The electronic part 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, 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 about hydrogen are available on the WIKA website. In Confidential have any more questions, your contact will gladly assist you to.