Ex protection for dial thermometers: New standard = new marking

Mechanical measuring instruments for use in explosive atmospheres can now be evaluated relative to a new standard: DIN EN ISO 80079-36/37 will replace EN 13463-1/5, with the transition period ending on 31 October 2019. For the initial instruments, WIKA has classified the model 73 and model 74 gas-actuated thermometers in accordance with the new directive and has issued the corresponding declaration of conformity. What does this change mean for an individual?
Firstly, & most importantly, the internationally valid ISO 80079 (date of application: 01 December 2016) has taken over the safeness requirements of EN 13463. Both of the gas-actuated thermometers evaluated by WIKA therefore remain constructionally and functionally unchanged.
Decreasing difference is the marking of the instruments. The information on the dial and the merchandise label correspond to certain requirements of both ISO 80079 and those of the new ATEX directive, 2014/34/EU:
ATEX 2014/34/EU
ISO 80079-36/37
A
B
C
D
E
1
2
3
4
5
6
II
2
G
Ex
h
IIC
T6 ? T1
Gb
X
II
2
D
Ex
h
IIIC
T85�C ? T450�C
Db
X
For Awe-inspiring , the note on the type of protection is of particular interest ? the letter ?h? certifies that the mechanical instrument gets the basic suitability for used in explosive atmospheres. The prior conventional information on the ignition protection type ?c? (protection through constructive safety) is no longer required. However, the criteria for the fulfilment of the and other forms of protection are also contained in the new standard, and WIKA has, as before, followed the requirements for ignition protection type ?c? in the current conformity assessment.
The new marking is explained at length in the following tables:
ATEX 2014/34/EU
ID
Marking
Sign
Meaning
A
CE marking
Communaut�s Europ�ennes / European communities
B
Specific marking for explosion protection
C
Equipment group
II
Equipment intended for use in other areas than underground parts of mines, and in those elements of surface installations of such mines, prone to be endangered by firedamp and/or combustible dust and also via an explosive atmosphere.
D
Instrument category
2
High safety (approved for zone 1 and 21)
E
Ex atmosph�re
G
Suitable for areas in which explosive gas, vapour, mist and air mixtures are present.
D
Suitable for areas where explosive atmospheres caused by dust can form.
ISO 80079-36/37
ID
Marking
Sign
Meaning
1
Ex marking
Ex
Per ISO80079-36/37
2
Type of protection
h
Non-electrical equipment for explosive atmospheres
3
Suitable atmosphere
IIC
Gas (group IIC)
IIIC
Combustible suspended solids, conductive dust and non-conductive dust
4
Maximum surface temperature*
T6 ? T1
Temperature class
T85�C ? T450�C
Max. surface temperature
5
EPL (new: Explosion Protection Level)
Gb
Protection from ignition sources which are effective or may become effective during normal operation and expected malfunction.
Db
6
Special application conditions (see instructions)
X
Ambient temperature with special range (here special operating conditions apply)
* The specific maximum surface temperature depends not on the gear itself, but mainly on the operating conditions.
Note
Further information on the model 73 and model 74 gas-actuated thermometers and also the corresponding declaration of conformity can be found on the WIKA website.

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