Ex protection for dial thermometers: New standard = new marking

Mechanical measuring instruments for use in explosive atmospheres is now able to be evaluated in accordance with 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 High Tech , WIKA has classified the model 73 and model 74 gas-actuated thermometers relative to the new directive and contains issued the corresponding declaration of conformity. What does this change mean for the user?
Firstly, & most importantly, the internationally valid ISO 80079 (date of application: 01 December 2016) has had over the basic safety requirements of EN 13463. Both of the gas-actuated thermometers evaluated by WIKA therefore remain constructionally and functionally unchanged.
Preposterous 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 brand 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 the user, the note on the sort of protection is of particular interest ? the letter ?h? certifies that the mechanical instrument has the basic suitability for used in explosive atmospheres. The prior conventional information on the ignition protection type ?c? (protection through constructive safety) is not any 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 today’s conformity assessment.
The brand new marking is explained at length in the next 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 places than underground elements of mines, and in those parts of surface installations of such mines, liable 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 that are effective or could become effective during normal operation and expected malfunction.
Disadvantages (see instruction manual)
X
Ambient temperature with special range (here special operating conditions apply)
* The specific maximum surface temperature depends not on the equipment itself, but mainly on the operating conditions.
Note
More info on the model 73 and model 74 gas-actuated thermometers plus the corresponding declaration of conformity can be found on the WIKA website.

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