4
4. TYPE nA CERTIFICATION
The BA474ND transmitter is Ex nA certified allowing
the instrument and the associated sensor to be
installed in a Zone 2 hazardous area without the
need for Zener barriers or galvanic isolators.
The transmitter sensor input, terminals 1, 2, 3 & 4, is
certified galvanically isolated and intrinsically safe Ex
[ia]. When the BA474ND transmitter is installed in a
Zone 2 hazardous area, the input terminals may
therefore be directly connected to a sensor in Zone 0
or 1 without the need for Zener barriers or galvanic
isolators.
4.1 ATEX certificate
Notified Body Intertek Testing and Certification Ltd
have issued the BA474ND with an EC-Type
Examination Certificate number ITS09ATEX26157.
The transmitter bears the community mark and
subject to local codes of practice may be installed in
any of the European Economic Area (EEA) member
countries. ATEX certificates are also acceptable for
installations in Switzerland.
This main section of this instruction manual describes
ATEX installations in explosive gas atmospheres
conforming with EN 60079-14 Electrical Installations
in Hazardous Areas. When designing systems for
installation outside the UK the local Code of Practice
should be consulted.
For use in the presence of combustible dust, please
refer to Appendix 1, which describes ATEX
installations complying with EN 61241-14.
4.2 Zones, gas groups and T rating
The BA474ND has been certified as Group II
Category 3G Ex nA IIC T5 apparatus, permitting
installation in:
Zone 2 explosive gas air mixture not likely
to occur, and if it does will only
exist for a short time.
Be used with gases in groups:
Group A propane
Group B ethylene
Group C hydrogen
Having a temperature classification of:
T1
450oC
T2
300oC
T3
200oC
T4
135oC
T5
100oC
At an ambient temperature between –20 and +60
o
C.
Notes
:
a. The guaranteed operating temperature range of
the BA474ND Indicating Temperature Transmitter
is –40 to +70
o
C for the transmitter and –20 to
+70
o
C for the display.
b. The BA474ND also has ATEX Ex nL [energy
limiting] certification, but following de-harmonising
of EN 60079-15:2005 in May 2013 this type of
protection has been replaced by Ex ic [intrinsically
safe in normal operation i.e. without faults].
4.3 Intrinsically safe Sensor input
terminals 1, 2, 3 & 4.
In addition to Ex nA certification, the ATEX certificate
states that the BA474ND Indicating Temperature
Transmitter,
‘incorporates a galvanically isolated
intrinsically safe input that permits direct connection
to measuring elements in any gas hazardous Zone.’
This is the sensor input, terminals 1, 2, 3 & 4, which
is certified as Group II Category (1) G Ex [ia] IIC T5.
When the BA474ND transmitter is located these
permits direct connection to sensors installed in:
Zone 0
explosive gas air mixture
continuously present.
Zone 1
explosive gas air mixture
likely to occur in normal
operation.
With a gas in groups:
Group A propane
Group B ethylene
Group C hydrogen
Thermocouples, resistance thermometers and
potentiometers comply with the requirements for
simple apparatus.
i.e. generate less than 1.5V;
100mA or 25mW and may be connected to the
transmitter input without a safety analysis. Active
devices, such as a voltage source, may also be
connected providing safety is assessed using the
entity concept.
The intrinsic safety parameters for sensor terminals
1, 2, 3 & 4 are:
Uo
=
6.0V
Io
=
30.3mA
Po =
46mW
Ui
=
6.0V
Ii
=
100mA
Pi
=
0.194W
Co
=
23.8µF
Lo
=
3mH