Rockwell Automation 1797-XXX FLEX Ex System Certification Reference Manual - Manual (Page 8)

Publication 1797-6.5.6 - June 2005
Preface 4
Division/Zone Designations
Division/Zone identifies the likelihood of a hazardous atmosphere being
present.
Gas/Dust Groups
Hazardous locations are grouped according to their ignition properties.
Division Method
(North America) IEC Standard
Zone Method
Ignitable mixture present continuously
(long periods)
Division 1
Zone 0
(Zone 20-Dust)
Ignitable mixture present intermittently
Zone 1
(Zone 21-Dust)
Ignitable mixture is not normally present Division 2
Zone 2
(Zone 22-Dust)
Typical Gas IEC Gas Group North American Gas Group
Acetylene IIC A
Hydrogen IIC B
Ethylene IIB C
Propane IIA D
Methane 1 I D 1
Metal Dust - E
Coal Dust - F
Grain Dust - -
1 Mining applications under jurisdiction of MSHA.