Rheonics | Switzerland | U.S.A.
SRV, SRD, SRV-FPC, SRD-FPC Installation and Intrinsic Safety Manual
P. 9
Version 2.0, Updated: October 29, 2020
Rheonics GmbH, Klosterstrasse 19, 8406 Winterthur, Switzerland
©Rheonics. Rheonics confidential and proprietary information.
3.1.
General note on Category of protection and operating zone
3.2.
Description of “X” conditions: operating conditions not described on the
label, but that are necessary in order to maintain intrinsic safety
Certain operating conditions must be met in order to ensure that the sensors and their
associated Zener diode barriers meet intrinsic safety criteria. These include:
•
Electrical parameters
•
Operating temperature ranges
•
Safe hydrostatic pressure limits
•
Maintenance of ingress protection
•
Protection against mechanical impact
•
Protection against solid materials transported by fluid being monitored
3.2.1.
Area classification & Gas Grouping
Area classification
Zone 1
Area in which an explosive gas atmosphere is likely to occur in
normal operation occasionally
Zone 2
Area in which an explosive gas atmosphere is not likely to occur in
normal operation and if it does occur, is likely to do so only
infrequently and will exist for a short period only
Zone 21
Place in which an explosive atmosphere in the form of a cloud of
combustible dust in air is likely to occur in normal operation
occasionally
Zone 22
Place in which an explosive atmosphere in the form of a cloud of
combustible dust in air is not likely to occur in normal operation but,
if it does, will persist for a short period only
Gas Grouping
Group IIA
Propane
Group IIB
Ethylene
Group IIC
Hydrogen and Acetylene
Although the sensors are specified for Category 1 (hazardous Zone 0), they may also be used
for Categories 2 and 3 (Zones 1 and 2). However, if the sensor has been used in a Category 3
(Zone 2) installation, it is no longer safe to use in categories 1 and 2 (Zones 0 and 1), because
of the risk that the sensor has been damaged. It is the responsibility of the installer and the
end user to ensure that any Rheonics SRV or SRD sensor that has been used in a Category 2
installation is not re-used for Category 1 or 2 installations.
