Guide to Hazardous Locations
Explosive Dust Atmospheres
Ex Marking
Protection Concepts
US (NEC 500) and CA (CEC Annex J)
®
Type of protection
(not used in CA)
Type of Protection
General Requirements
Permitted Class
Dust-Ignitionproof for Class II,
Division 1, Groups E, F, G T5
Permitted Division
Temperature Class
(optional except for Division 2)
(T5 and T6 optional)
Permitted Class
Permitted Group
Dust-Ignitionproof
AEx
Ex
Ex
Ex
(DIP)
Dust-Protected
(NI)
Protection by Enclosure
AEx tD
AEx ta
Ex ta
Ex ta
Ex ta
AEx tb
Ex tb
Ex tb
Ex tb
AEx tc
Ex tc
Ex tc
Ex tc
(DIP)
Ambient temperature ranges other than standard (-25°C ≤ Ta ≤ +40°C)
must be marked.
US (NEC® 506 per 61241)
American National Standard
Temperature Classification
Zone 21 AEx tD T120°C
Permitted Zone
Type of Protection
Ambient temperature ranges other than standard (-20°C ≤ Ta ≤ +40°C) must
be marked.
Fiber + Flying Protection
US (NEC® 506 per 60079)
Encapsulation
American National Standard
Temperature Class
Equipment Group
Zone 21, AEx tb IIIC T120°C Db
Permitted Zone
Type of Protection
Equipment Protection Level
(optional)
Ambient temperature ranges other than standard (-20°C ≤ Ta ≤ +40°C) must
be marked.
EU and IEC (per 60079) and CA (CEC Sect 18)
Pressurization
Equipment Group Temperature Class
Ex tb IIIC T120°C Db
Type of Protection
Equipment Protection Level
Ambient temperature ranges other than standard (-20°C ≤ Ta ≤ +40°C)
must be marked.
EU (Directive 94/9/EC) ATEX
CE Conformity Marking
Explosion Protection Marking
Intrinsic Safety
Category (including “D” for dusts)
1725
II 2 D
Equipment Group
Identification Number of Notified Body
Involved in Production Control Stage
EPL/Category
IEC
Definition
EPL
Dust atmospheres,
“very high” level
of protection
Da
Dust atmospheres,
“high” level
of protection
Db
Dust atmospheres,
“enhanced” level
of protection
Dc
Code
EU (ATEX)
Group Category Group
Typical Zone
of Application
1D
III
2D
20
II
3D
21
AEx ma
Ex ma
Ex ma
Ex ma
AEx maD
AEx mb
Ex mb
Ex mb
Ex mb
AEx mbD
AEx mc
Ex mc
Ex mc
Ex mc
(PX)
(PX)
(PY)
(PY)
(PZ)
(PZ)
AEx pD
Ex pD
Ex pxb
Ex pxb
Ex pyb
Ex pyb
Ex pzc
Ex pzc
(I.S.)
(I.S.)
AEx ia
Ex ia
Ex ia
Ex ia
AEx iaD
Ex iaD
AEx ib
Ex ib
Ex ib
Ex ib
AEx ibD
Ex ibD
AEx ic
Ex ic
Ex ic
Ex ic
(I.S.)
(I.S.)
Market Application
Standard
US
CA
US
CA
US
CA
EU
IEC
US
CA
US
CA
US
US
CA
EU
IEC
US
CA
EU
IEC
US
CA
EU
IEC
US
CA
US
CA
EU
IEC
US
US
CA
EU
IEC
US
US
CA
EU
IEC
US
CA
US
CA
US
CA
US
EU
EU
IEC
EU
IEC
EU
IEC
US
CA
US
CA
EU
IEC
US
EU
US
CA
EU
IEC
US
EU
US
CA
EU
IEC
US
CA
FM 3600
CSA C22.2 No. 0
FM 3600
CSA C22.2 No. 0
ISA 61241-0 or ISA 60079-0
CSA C22.2 No. 60079-0
EN 60079-0
IEC 60079-0
FM 3616
CSA C22.2 No. 25
FM 3611
CSA C22.2 No. 25
ISA 61241-1
ISA 60079-31
CSA C22.2 No. 60079-31
EN 60079-31
IEC 60079-31
ISA 60079-31
CSA C22.2 No. 60079-31
EN 60079-31
IEC 60079-31
ISA 60079-31
CSA C22.2 No. 60079-31
EN 60079-31
IEC 60079-31
FM 3611
CSA C22.1
ISA 61241-18
CSA C22.2 No. 60079-18
EN 60079-18
IEC 60079-18
ISA 61241-18
ISA 60079-18
CSA C22.2 No. 60079-18
EN 60079-18
IEC 60079-18
ISA 61241-18
ISA 60079-18
CSA C22.2 No. 60079-18
EN 60079-18
IEC 60079-18
FM 3620 (NFPA 496)
NFPA 496
FM 3620 (NFPA 496)
NFPA 496
FM 3620 (NFPA 496)
NFPA 496
ISA 61241-2
EN 61241-4
EN 60079-2
IEC 60079-2
EN 60079-2
IEC 60079-2
EN 60079-2
IEC 60079-2
FM 3610
CSA C22.2 No. 157
ISA 60079-11
CSA C22.2 No. 60079-11
EN 60079-11
IEC 60079-11
ISA 61241-11
EN 61241-11
ISA 60079-11
CSA C22.2 No. 60079-11
EN 60079-11
IEC 0079-11
ISA 61241-11
EN 61241-11
ISA 60079-11
CSA C22.2 No. 60079-11
EN 60079-11
IEC 60079-11
FM 3610
CSA C22.2 No. 157
Class II, Division 1 & 2
Class II, Division 1 & 2
Class III, Division 1 & 2
Class III, Division 1 & 2
Zone 20, 21, & 22
Zone 20, 21, & 22
Category 1D, 2D, & 3D
EPL Da, Db, & Dc
Class II, Division 1
Class II, Division 1
Class II, Division 2
Class II, Division 2
Zone 21
Zone 20
Zone 20
Category 1D
EPL Da
Zone 21
Zone 21
Category 2D
EPL Db
Zone 22
Zone 22
Category 3D
EPL Dc
Class III, Division 1 & 2
Class III, Division 1 & 2
Zone 20
Zone 20
Category 1D
EPL Da
Zone 20
Zone 21
Zone 21
Category 2D
EPL Db
Zone 21
Zone 21
Zone 22
Category 2D
EPL Dc
Class II, Division 1
Class II, Division 1
Class II, Division 1
Class II, Division 1
Class II, Division 2
Class II, Division 2
Zone 21
Category 2D
Category 2D
EPL Db
Category 2D
EPL Db
Category 3D
EPL Dc
Class II, Division 1
Class II, Division 1
Zone 20
Zone 20
Category 1D
EPL Da
Zone 20
Category 1D
Zone 21
Zone 21
Category 2D
EPL Db
Zone 21
Category 2D
Zone 22
Zone 22
Category 3D
EPL Dc
Class III, Division 1
Class III, Division 1
Protection Principle
Canada
C
C
EU (ATEX)
C
US
US
In the United Kingdom: FM Insurance Company Limited
1 Windsor Dials, Windsor, Berkshire, SL4 1RS
Authorized by the Prudential Regulation Authority and regulated by the
Financial Conduct Authority and the Prudential Regulation Authority.
P08298 © 2013 FM Approvals
(05/2015) All rights reserved.
fmapprovals.com
Zone 21
Zone 22
Zone 21
Zone 22
Division 2
Zone 22
Division 1
Zone 20
Zone 21
Division 1
Division 2
IEC (60079)
US (NEC 506)
CA (CEC Section 18)
US (NEC 506)
per 61241
US (NEC 500)
CA (CEC Annex J)
IIIC
N/A
Class II, Group E
IIIB
D
Class II, Group F
IIIB
D
Class II, Group G
IIIA
D
Class III
Metal dusts
Carbonaceous dusts
Non-conductive dusts
Fibers and flyings
61241 did not differentiate between different materials, but referred to all with a “D” suffix on the Type of Protection.
Keep
combustible
dust out
Temperature
Marking
T1
T2
T2A
T2B
T2C
T2D
T3
T3A
T3B
T3C
T4
T4A
T5
T6
450°C
300°C
280°C
260°C
230°C
215°C
200°C
180°C
165°C
160°C
135°C
120°C
100°C
85°C
US NEC 500/CA CEC Annex J Class II or III
For Class II, the temperature class is determined
with a maximum dust layer* on the equipment.
For installation, that temperature class must
not be greater than the dust layer or dust cloud
ignition temperature.
For organic dusts that may dehydrate or carbonize,
temperature classes greater than “T3B” (165°C)
are not permitted.
For Class III, the temperature is determined with
a maximum dust layer* on the equipment.
No temperture
marking
The temperature must not be greater 120°C for
equipment that can be overloaded and 165°C for
equipment not subject to overloading.
Marking
US NEC 506/CA CEC Sect 18
EU/IEC
Temperature is determined
with no dust layer on
the equipment.
T___°C
Temperature class
in degrees Celsius
preceded by a “T”
e.g. T120°C
Limit
energy of
sparks and
surface
temperature
TL ___°C
Temperature class
in degrees Celsius
preceded by a “TL”
with a dust layer of
“L” where “L” is the
layer depth in mm
e.g. T150120°C
Temperature is determined
with a maximum dust layer*
on the equipment.
For installation, that temperature must not be greater
than the dust layer or dust
cloud ignition temperature.
For installations with
layers up to 5mm thick,
that temperature must be
at least 75K below the dust
layer ignition temperature
and no more 2/3 of the dust
cloud ignition temperature.
For installations with layers
up to 50mm thick, IEC/
EN 60079-14 provides
information on reduction
of temperature.
Not recognized
Temperature is determined
with specified layer depth,
(> 50 mm) on all sides of
the equipment. That temperature must be at least
75K below the dust layer
ignition temperature and
no more 2/3 of the dust
cloud ignition temperature.
* A maximum dust layer is a layer or blanket of wheat flour, corn flour, or grain dust that results
from the equipment being covered with dust until no more will stay on the equipment.
Ingress Protection (IP) Codes
First characteristic Numeral
Second characteristic Numeral
Protection against solid bodies
No protection
0
Objects greater than 50mm
1
Objects greater than 12mm
2
Objects greater than 2.5mm
3
Objects greater than 1mm
4
Dust-protected
5
Dust-tight
6
Protection against liquid
No protection
Vertical (90˚) dripping water
75˚ to 90˚ dripping water
Sprayed water
Splashed water
Water jets
Heavy seas
Temporary immersion
Continuous immersion
High pressure/temperature water jet
7
8
9
Approximate U.S. enclosure type equivalent to IPXX
Type
1
2
3
3R
FM Approvals can also issue IECEx Test Reports, Quality Assessment Reports and Certificates of Conformity.
FM Approvals
1151 Boston-Providence Turnpike, Norwood, MA 02062-9102
Phone: +1 (1)781 255 4851 Fax: +1 (1)781 762 9375
E-mail: information@fmapprovals.com
Zone 20
Typical material
FM Approvals is your global conformity assessment solution
U.S.
Zone 20
Combustible
Dust Present
Abnormally
Equipment Grouping
EU (60079)
Note 2: For associated intrinsically safe apparatus not suitable for installation in a hazardous location, both the symbol “Ex” or “AEx” and the symbol for the type of protection
“iaD” “ibD”, “ia”, or “ib” are enclosed within the same square brackets, e.g. [AEx iaD] or [AEx ia] IIIC; in this case, a temperature class is not included.
Recognized product certification marks
Combustible
Dust Present
Intermittently
US area classification per ANSI/NFPA 70 National Electrical Code® (NEC®) Article 500 or Article 506
CA area classification per CSA C22.1 Canadian Electrical Code (CEC) Section 18
EU area classification per EN 60079-10-2
IEC area classification per IEC 60079-10-2 or IEC 61241-10
Note 1: For associated intrinsically safe apparatus suitable for installation in a hazardous location, the symbol for the type of
protection “iaD”, “ibD”, “ia”, or “ib” are enclosed within square brackets, e.g. Zone 21 AEx tb [ia] IIIC T135°C or Zone 21 AEx tD [iaD] T135°C.
Market
Dust Present
Continuously
IEC / EU
US (NEC® 506)
US (NEC® 500)
CA (CEC Section 18)
CA (CEC Annex J18)
22
Level of protection assigned to equipment based on its likelihood of becoming
a source of ignition
Area Classification
Combustible
IP
10
11
54
14
Type
IP
3S 54
4 and 4X 55
5 52
Type
IP
6 and 6P 67
12 and 12K 52
13 54
Acronyms
ATEX
CA
CEC
EPL
EU
IEC
I.S.
Canadian Electrical Code (CSA C22.1) NFPA
Equipment Protection Level
NEC
Atmosphère explosible
Canada
European Union
US
International Electrotechnical Commission
Intrinsic Safety
National Fire Protection Association
National Electrical Code (NFPA 70)
United States of America