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4 SENSOR SAFETY DESCRIPTION
4.1 HAZARDOUS AREAS
The sensor may be installed in a metal stack or duct containing hazardous dust, while any ancillary equipment must be
installed in the designated Safe Area. The sensor unit is mounted to the ductwork such that the metal probe rod protrudes
into the flow of the particulate to be monitored.
4.1.1 Hazardous Zone Classification
The instrument is suitable for use in the following Ex zones:
Gas zone
Dust zone
4.2 CENELEC CODES
4.2.1 Gas Atmospheres
The marking for explosive gas atmospheres includes the following CENELEC codes (see also section 4.5 below):
Ex nA IIB T6 Gc for the sensor enclosure.
•
Ex nA IIB T3 Gc for the sensor body and probe when the maximum stack ambient is +200°C.
•
The nA applies to the non-sparking connections, and also signifies that the equipment is incapable in normal
operation of producing sparks or hot surfaces that may cause ignition.
4.2.2 Dust Atmospheres
The marking for explosive dust atmospheres includes the CENELEC codes (see also section 4.5 below):
Ex tc IIIC T80°C Dc for the sensor enclosure.
•
Ex tc IIIC T200°C Dc for the sensor body and probe when the maximum stack ambient is +200°C.
•
The tc applies to protection by enclosure, and also signifies that the equipment is incapable in normal operation
of producing sparks or hot surfaces that may cause ignition.
4.3 SPECIAL CONDITIONS OF SAFE USE FOR SENSOR ENCLOSURE
a) All connections to the equipment must not be inserted or removed unless the area in which the equipment is installed
is known to be non-hazardous, or the circuit to which it is connected has been de-energized. This includes the plugging/
unplugging of the screw terminals from the PCB-mounted headers.
b) Neither the enclosure nor any of the labels attached to it are to be rubbed with a dry cloth or anything else that might
cause a build-up of electrostatic charge.
c) A connection must be made between the earth stud on the outside of the enclosure and the duct wall. The connection
shall be made as follows
The cable shall have a cross-sectional area of at least 4 mm².
•
The cable shall be connected using an anti-vibration nut and washer or a similar arrangement of comparable integrity.
•
If the probe is removed while a potentially flammable dust or gas is present, this connection shall be maintained during the
withdrawal of the probe.
d) This equipment is suitable for an ambient temperature range of –20°C to +50°C and the standard range of atmospheric
pressure; the user/installer shall ensure that the process temperatures and pressures, including within the dust stack,
do not cause these parameters to be exceeded.
06
INSTALLATION AND OPERATION MANUAL – OWNER'S RECORD FFD MANUAL – FILTER FAILURE DETECTOR
INSIDE STACK
OUTSIDE STACK
Zone 2
Zone 2
Zone 22
Zone 22
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