WIKA R5502 Mode D'emploi page 11

5. Special conditions for use (X conditions)
Instruments for use in hazardous gas/air, vapour/air and mist/air
atmospheres:
Temperature class
(gas application)
T6
T5
T4
T3
T2
T1
1) only for instruments without liquid filling
Hazardous dust atmosphere
For dusts, the procedure specified in ISO/IEC 80079-20-2 for
determining the ignition temperature has to be applied. The ignition
temperature is determined separately for dust clouds and dust layers,
respectively. For dust layers, the ignition temperature depends on the
dust layer thickness per EN/IEC 60079-14.
Ignition temperature
of dust
Dust cloud T
cloud
Dust layer T
layer
The permissible maximum medium temperature must not exceed the
lowest determined value, even in case of a malfunction.
3) Mount the instrument in such a way that, taking into consideration
the influence of convection and heat radiation, no deviation above or
below the permissible ambient and medium temperatures can occur.
4) The end user must ensure that the measuring instrument is
connected to the equipotential bonding of the end-use application via
the process connection. The sealings used at the process connection
must be electrically conductive.
WIKA operating instructions models 53, 54, 55 (ATEX)
Maximum permissible surface
temperature (for the end application)
+65 °C
+80 °C
+105 °C
+160 °C
+240 °C
+250 °C (+360 °C)
Maximum permissible medium
temperature (in the measuring system)
< 2/3 T
cloud
< T − 75 K − (reduction depending on the
layer
layer thickness)
1)
EN
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