PSV & ATEX

[petrona]

Hi
i red in 94/9/CE guideline that safety protection system needs only Ex specific marking, it's true?

what is the correct marking (PSV in Zone 2, explosion atmosphere by gasoline vapours)?
1) Ex
2) Ex - II
3) Ex - II 2G
4) Ex - II 2G - IIB
5) Ex - II 2G - IIB TX
6) Ex - II 2G - IIB T3
thanks

 

[micalbrch]

First Zone 2 means Ex II 3G, not 2G.

Second: I never heard of a (spring loaded) PSV which has a special marking acc. to 94/9/CE. What shall be the ignition source?

I know that LESER went through the 94/9/CE for their safety valves and the result is that the valves can be used for all group II installations. But the valves are not especially stamped. That would only be necessary if there are any restictions.

 

[petrona]

category group applicable for zone 2:
1G, 2G, 3G

possible ignition source:
- surface temperature
- electrostatic charges

I think micalbrch's right but I want to have documented confirmation, if there is one

 

[MortenA]

If your are thinking about CE markign and ATEX then i dont think that PSV's are subjected to this. CE marking with regards to ATEX are strictly for electrical systems. An actuated valve will need it because of the electronics in the actuator (e.g. the solenoid valve) - but if the system was purely mechancal e.g. springs and pneumatics then i actually dont know?

Best regrads

Morten

 

[micalbrch]

Also purely mechanical devices and machines are subjected to ATEX. But if there is no ignition source, then there is no ATEX.

The surface temperature is not caused by the valve but only by the fluid. So, that is not an ignition source caused by the valve. Electrostatic? If there is no plactic in the valve, then there will no electrostatic.