Class 1, Div 2 Gp D equivalent in Europe 1

[579927]

Hi there,

I am trying to find the equivalent of Class 1, Div 2, Gp D in European standards.

Thank you

 

[JLSeagull]

Start with a review af the NEC article 505. This covers zones 0, 1 and 2. My understanding is that Zone 1 is much the same as Division 1 for gas present 10-1000 hours per year. Zone 2 is much the same as Division 2 with gas present less than 10-hours per year. Zone zero applies to the internal space such as the space within a tank or sump. Zone zero and ATEX apply to flammable gas always present or greater than 1000 hours per year. For dust Zone 21 is like Division 1 and Zone 22 is like Division 2. See IEC 60079-10, ATEX Directive 94/4/EC and CENELEC EN 60079-10 if applicable. I don't have a copy of these standards to verify the details. Also refer the inversed sequence of the groups. Groups A and B in the NEC are similar to IEC Group IIC, Group C is similar to Group IIB and Group D is similar to Groupp IIA. Check the latest editions of API RP 500, NFPA RP 497 and 325, etc. These tables may be aligned with the IEC standards for the selected gas, flammable liquid and combustible liquid chemicals.

 

[DRWeig]

Nicely phrased, JLSeagull! I concur completely.

Good on ya,

Goober Dave

 

[rbalex]

Actually, it doesn’t take too much review of NFPA 497 Table 4.4.2 to see there are quite a few "maverick" gasses with respect to “Groups” and there isn't necessarily any direct correlation. Group C is the most free-spirited. It is usually Group IIA, but occasionally Group IIB; even a few Group Ds, like Methyl Acetate will wander over to Group IIB. Annex A, Table A 3.3.5.1 explains why this happens – the basic test methods are different and the Minimum Experimental Safe Gap (MESG) values are significantly different.

While it may be customary by some recommended practices, neither classic IEC Zones, nor NEC Zones actually specify a time duration envelope. Careful reading of classic IEC Zones will find them defined in terms of “probability;” whereas, US Divisions and Zones are ultimately defined in terms of “possibility.” Article 505 “force-fit” Zones into the classic Division model. While IEC Zone 0 would always be Division 1, IEC Zone 1 could be either Division 1 or Division 2. Even at the “bottom end” what may have been classified Zone 2 or Division 2 by one system may be “unclassified” by the other.

All that being said Class I, Division 2, Group D is most likely Zone 2, IIA – unless its Methyl Acetate, of course. (Side note: Simply calling it “Zone 2” automatically specifies that it is Class I, “Zone 2x” specifies Classes II & III)