Appendix 1
ATEX Dust Certification
In addition to ATEX certification permitting
installation in explosive gas atmospheres which is
described in the main section of this instruction
manual, all BA358E Rate Totalisers have ATEX
certification permitting installation in combustible
dust atmospheres.
This appendix describes ATEX installations in
explosive dust atmospheres conforming with
EN 60079-14 Electrical installations design,
selection and erection. When designing systems
for installation outside the UK the local Code of
Practice should be consulted.
The Rate Totaliser’s dust input and output safety
parameters are identical to the gas safety
parameters, so all the electrical circuits shown in
the main section of this manual may also be used
for dust applications.
A1.1
Zones, and Maximum Surface
Temperature
The BA358E has been ATEX certified as Group II,
Category 1D Ex ia IIIC T80ºC Da IP20 apparatus,
Ta -40 to 70°C.
When connected to a suitable system the Rate
Totaliser may be installed in:
Zone 20
explosive atmosphere in the form of
a cloud of combustible dust in air is
continuously present, or for long
periods or frequently.
Zone 21
explosive atmosphere in the form of
a cloud of combustible dust in air is
likely to occur occasionally in normal
operation.
Zone 22
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 occur, will
only persist for a short period.
Be used with dust in subdivisions:
IIIA
combustible flyings
IIIB
non-conductive dust
IIIC
conductive dust
(For use with IIIC conductive
dusts special conditions for safe
use apply – see section A1.4)
Having a Minimum Ignition Temperature of:
Dust cloud
120°C
Dust layer on Rat Totaliser 155
°
C
up to 5mm thick
Dust layer on Rate Totaliser Refer to
over 5mm thick.
EN 60079-14
At an ambient temperature between -40 and +70°C
Note:
The specified operating temperature of the
BA358E is –20 to +70ºC. At temperatures below
–20ºC the instrument will continue to totalise but
the display will not function.
A1.3 Maintenance
ENSURE PLANT SAFETY BEFORE
STARTING MAINTENANCE
Live maintenance is permitted on
intrinsically safe equipment installed in a
hazardous area, but only certified test
equipment should be used.
All models have IP66 front of panel protection and
a gasket is provided to seal the joint between the
instrument and the mounting panel thus preventing
dust ingress from the outside of the mounting
panel. The rear of the instruments is not sealed,
but ATEX dust certification is dependent on the
internal conformal coating of the instrument, so
dust ingress is acceptable except for use in IIIC
conductive dusts – see A1.4. However, it is good
practice to minimise the amount of dust
accumulating on the rear of the instrument.
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