ExplosionProtection
An International Comparison Guide for the Oil & Gas Industry
USA & CANADA
EUROPE
(National Electrical Code / Canadian Electrical Code)
(Atmosphere Explosive)
Explosion Protection
1.0 Hazardous-Area Classification
Hazardous
locations
are
defined
as
areas
where
fire
or
explosion
hazards
may
exist
due
to
the
presence of flammable gases or vapours, liquids or dusts.
•
•
1.2 European Classification (CENELEC)
1.3 Australian Classification (IEC)
1.4 IEC Classification (NEC 505, CEC Section 18)
•
•
Within Europe, the ATEX directives are imposed as a minimum requirement for Ex
legislation.
•
Australia has also implemented the IEC’s International Zoning System.
•
The IEC’s International Zoning System has become increasingly accepted worldwide.
•
ATEX 1999/92/EC enforces hazardous area classification of work places into zones
depending on the frequency and time that an explosive atmosphere is present.
•
For further information on the Australian IEC hazardous classification system,
see: AS/NZS60079.10
(NB. This standard has replaced the formally, AS2430.1)
•
Although the IEC’s system aims to create a standardised approach to
Explosion Protection, users and manufactures should be aware that
many nations such as the US have incorporated a number of countryspecific deviations in order to comply to current wiring methods under the NEC.
North American Ex standards in both the US and Canada follow two different
approaches;
the
traditional
‘Class,
Division’
method
under
NEC
500 (US) / CEC Annex J (Canada) and the new, ‘International Zoning System’ under NEC 505 (US) / CEC Section 18 (Canada).
Flammable Atmosphere
Present Continuously
ZONE 1
*DIVISION 1
ZONE 2
*DIVISION 2
CEC Section 18
CEC Annex J
ZONE 0
*DIVISION 1
ZONE 1
*DIVISION 1
ZONE 2
*DIVISION 2
Groups further define the type of hazard in a Class I location:
Group Type
Group A
Group B
Group C
Group D
Group A hazards represent
gases with extremely high
explosion
pressures
while
Group D represent gases with
lower explosion pressures.
Temperature classes are assigned to indicate the safe working limit
of the gases and vapours that could be present in a hazardous area.
Throughout the world, differing country-specific standards impose
different equipment marking methods, so it is important to
understand how they compare.
•
For more information, visit www.pyroban.com/information-faq.html
•
•
Atmospheres containing...
Acetylene & similar gases
Hydrogen & similar gases
Ethylene, & similar gases
Propane & similar gases
Maximum Surface Temp.
450˚ C (842˚F)
300˚ C (572˚F)
280˚ C (536˚F)
260˚ C (500˚F)
230˚ C (446˚F)
215˚ C (419˚F)
200˚ C (392˚F)
T Class
T1
T2
T2A
T2B
T2C
T2D
T3
Maximum Surface Temp.
180˚ C (365˚F)
165˚ C (329˚F)
160˚ C (320˚F)
135˚ C (275˚F)
120˚ C (248˚F)
100˚ C (212˚F)
85˚ C (185˚F)
ZONE 1
ZONE 2
IEC
For more information, visit www.pyroban.com/aus
Flammable Atmosphere
is likely to occur in normal
operation
Flammable Atmosphere
is not likely to occur in
normal operation
ZONE 0
ZONE 1
ZONE 2
•
IEC 60079-10 - Electrical Apparatus for Explosive Atmospheres, Classification of
Hazardous Areas.
•
Australia has adopted the IEC methods of classifying explosion groups.
•
•
Hazardous
areas
with
gas
or
vapours
present
designated Group II locations and the gases which make up
atmosphere are sub-categorised under the IEC’s three groups, A, B and C.
Group Type
Group A
Group B
Group C
ATEX has adopted the IEC’s methods of temperature classification,
appointing a more generalised classification to a range of temperatures
rather than the North American approach, using a number of further T-Classes.
Maximum Surface Temp.
˚C
˚F
450˚ C
842˚ F
300˚ C
572˚ F
200˚ C
392˚ F
135˚ C
275˚ F
100˚ C
212˚ F
85˚ C
185˚ F
T Class
T3A
T3B
T3C
T4
T4A
T5
T6
ZONE 0
Flammable Atmosphere
Present Continuously
2.4 IEC Explosion Groups (NEC 505, CEC Sec. 18)
Group Type
Atmospheres containing...
Group A
Acetone, Methane & similar gases
Acetaldehyde, Ethylene & similar gases
Group B
Group C
Acetylene, Hydrogen, & similar gases
•
The traditional North American ‘Class, Division’ system uses a unique temperature
classification system to that adopted under the IEC.
Flammable Atmosphere
is not likely to occur in
normal operation
2.3 Australian Explosion Groups
These groups are defined under EN60079
Group
IIA
gases
represent gases most
difficult to ignite while
Group IIC represents
gases easiest to ignite
Flammable Atmosphere
is likely to occur in normal
operation
For further information on IEC hazardous classifications, see:
•
In comparison to the traditional North American standards, ATEX classifies
atmospheres containing flammable gases / vapours as Group II hazardous areas.
•
for more information, visit www.pyroban.com
•
•
•
Special precautions need to be taken in hazardous areas to prevent equipment
becoming a source of ignition.
Flammable Atmosphere
Present Continuously
Australia
ZONE 2
•
3.2 European Temperature Classification (CENELEC)
Different country-specific Ex standards have appointed
different temperature classification systems so it important to
ensure your Ex equipment is modified to the correct level
of protection.
Explosion Proof equipment should be supplied with certified
documentation and be clearly marked, displaying the measures
the equipment has undergone to operate in classified hazardous
areas.
ZONE 1
3.1 North American Temperature Classification (NEC 500 / CEC Annex J)
Equipment
and
apparatus
working
in
a
hazardous
area must
be designed / modified to the assigned TClass to ensure surface temperatures do not exceed the
ignition temperature of hazardous gases and vapours.
4.0 Equipment Marking / Certification
ZONE 0
Flammable Atmosphere
is not likely to occur in
normal operation
2.2 European Explosion Groups (CENELEC)
The NEC & CEC Division systems use Classes and Groups to identify a
hazard. The systems refer to Class I environments, where gases & vapours represent an explosive atmosphere, most commonly present in the oil and gas industry.
Worldwide, there are a number of different systems in place. The
traditional North American ‘Class, Division’ system uses a different
system to that used under ATEX in Europe and by the IEC, altering
the way in which equipment manufactures build and mark certified
Ex equipment.
3.0 Temperature Classifications
•
ATEX 1999/92/EC
2.1 North American Explosion Groups (NEC 500 / CEC Annex J)
•
•
Flammable Atmosphere
is likely to occur in normal
operation
Flammable Atmosphere
Present Continuously
* The Division classifications stated above are in accordance to Class 1 areas.
for more information, visit www.pyroban.com
•
Flammable Atmosphere
is not likely to occur in
normal operation
ZONE 0
*DIVISION 1
for more information, visit www.pyroban.com
•
Flammable Atmosphere
is likely to occur in normal
operation
NEC 505
NEC® 500
®
Hazardous area classification should be carried out as an
integral part of the risk assessment to identify areas where
control over ignition sources is needed.
Explosion groups are designated to classified hazardous areas to
identify the ignition related properties of an explosive atmosphere.
IECEx
(International Electrotechnical Commission)
1.1 North American Classification
Worldwide, differing Ex standards use Hazardous area
classifications to classify environments dependant on the
frequency and persistence of a potentially explosive atmosphere
occurring.
2.0 Explosion Groups
AS/NZS
ATEX
NEC / CEC
Essential Requirements
WORLDWIDE
AUSTRALIA
Atmospheres containing...
Acetone, Methane & similar gases
Acetaldehyde, Ethylene & similar gases
Acetylene, Hydrogen, & similar gases
are
the
•
The IEC’s apparatus grouping system has been adopted by the ATEX directives in
Europe and throughout the world, including the US (NEC 505) Canada (CEC Sec.
18) and Australia.
The groups below, assigned to gases and vapours are categorised as Group II
locations, as used in Europe.
Group Type
Group A
Group B
Group C
For more information on the
Australian IEC’s gas grouping
system, see: AS/NZS2430.3.4
Atmospheres containing...
Acetone, Methane & similar gases
Acetaldehyde, Ethylene & similar gases
Acetylene, Hydrogen, & similar gases
3.3 Australian Temperature Classifications
3.4 IEC Temperature Classification
•
•
Australia has also adopted the IEC methods of temperature classification.
•
Maximum Surface Temp.
˚C
˚F
450˚ C
842˚ F
300˚ C
572˚ F
200˚ C
392˚ F
135˚ C
275˚ F
100˚ C
212˚ F
85˚ C
185˚ F
T Class
T1
T2
T3
T4
T5
T6
Group
IIA
gases
are
similar to the NEC Group
D gases. Group IIB are
similar to NEC Group C while
IEC Group IIC gases are
similar to NEC group A & B.
The IEC’s new international approach has been adopted by many nations and Ex
standards.
For more information on IEC temperature classification, see: IEC 60079-20
Maximum Surface Temp.
˚C
˚F
450˚ C
842˚ F
300˚ C
572˚ F
200˚ C
392˚ F
135˚ C
275˚ F
100˚ C
212˚ F
85˚ C
185˚ F
T Class
T1
T2
T3
T4
T5
T6
T Class
T1
T2
T3
T4
T5
T6
4.1 North American Equipment Marking (NEC 500 / CEC Annex J)
4.2 European Equipment Marking (CENELEC)
4.3 Australian Equipment Marking
4.4 IEC Equipment Marking (IEC, NEC 505, CEC Sec. 18)
•
•
•
Electrical
equipment
used
in
a
hazardous
area
must
be
certified to the IEC or Australian standards via an acceptable
certification scheme. Acceptable schemes include IECEx, ANZEx and AUSEx.
•
•
Other equipment (e.g. ATEX, FM, UL) can usually be used if the legal owner
justifies and accepts their use and an assessment is made as to the equivalence in
safety of the equipment compared to IECEx / ANZEx or AUSEx equipment
NEC 500 / CEC Annex J Equipment Marking:
ATEX Equipment Marking:
Ex Standard
Typical Example of Equipment Marking
Ex Standard
NEC 500 /
CEC Annex J
CLASS 1, DIVISION 1, GROUPS A, B, C, D, T5
ATEX 94/9/EC
Typical Example of Equipment Marking
, II, 2G, Ex, de, IIC, T5
ATEX 94/9/EC
NEC 500 / CEC Annex J
(Class 1 = Hazard Class, Division 1 = Area Classification, Groups A, B, C, D = Permitted gas
groups, T5 = Equipment Temperature Class)
( = CE Conformity Marking,
= EU Explosion-Protection Marking, II = Equipment Groups [I = for
mines, II = for other than mines], [2 = Equipment Category, G = Type of Ex Atmosphere; G (Gas), D
(Dust)], Ex = Explosion Protected according to CENELEC standards, de = Protection Method, [II =
Apparatus Group, C = Gas Group], T5 = Temperature Class
for more information, visit www.pyroban.com
Ex Standard
Typical Example of Equipment Marking
AS/NZS2381
Ex, de, IIC, T5
IEC Equipment Marking:
Ex Standard
Typical Example of Equipment Marking
IEC & CEC Sec. 18
Ex, d, [ia], IIC, T5
NEC 505
Class I, Zone 1, AEx, d, [ia], IIC, T5
IEC & CEC Sec. 18:
AS/NZS2381:
Ex = Explosion-Protected, de = Protection technique, II = Apparatus Group, C = Gas Group, T5 =
Temperature Class
5.0 Protection Concepts, Methods & Standards
(Ex = Explosion-Protected, d = Type of
Protection, [ia] = I.S Output, II = Group,
C = Gas Group, T5 = Temperature Class
NEC 505:
(Class I = Permitted Class, Zone 1 = Permitted Zone,
AEx = American National Standard, d = Type of
Protection, [ia] = I.S Output, II = Group, C = Gas
Group, T5 = Temperature Class
5.1 Equipment Certified for Use
Protection
Method
Id. Letter
IEC
CENELEC
CSA (IEC)
CSA (Annex J)
NEC 505
NEC 500
AS/NZS
Type of Protection
Mode of Function
NEC 500 / CEC Annex J
Permitted Division
IEC / CENELEC
Permitted Zone
Flameproof
d
IEC 60079-1
EN 60079-1
CSA E60079-1
CSA C22.2 No. 30
ISA 60079-1
FM 3618
AS/NZS60079-1 / AS2380.2
Explosion is Contained
Enclosure contains internal explosion
Division 2
Zone 1 or 2
Intrinsic Safety
ia
IEC 60079-11
EN 60079-11
CSA E60079-11
CSA C22.2 No. 157
ISA 60079-11
FM3610
AS/NZS60079-11 / AS2380.7
Sparks are not ignition capable (Safe 2 faults)
I.S. circuits are unable to cause ignition
Division 1 or 2
Zone 0, 1 or 2
Intrinsic Safety
ib
IEC 60079-11
EN 60079-11
CSA E60079-11
CSA C22.2 No. 157
ISA 60079-11
FM3610
AS/NZS60079-11 / AS2380.7
Sparks are not ignition capable (Safe 1 faults)
I.S. circuits are unable to cause ignition
Division 2
Zone 1 or 2
Pressurisation
p
IEC 60079-2
EN 60079-2
CSA E60079-2
CSA TIL. E13 A
ISA 60079-2
FM 3620
AS/NZS60079-2 / AS2380.4
Flammable atmosphere is eliminated
Protection by over pressured enclosure
Division 1 or 2
Zone 1 or 2
Increased Safety
e
IEC 60079-7
EN 60079-7
CSA E60079-7
--------
ISA 60079-7
FM 3619
AS/NZS60079-7 / AS2380.6
Source of ignition eliminated
Division 2
Zone 1 or 2
Oil Immersion
o
IEC 60079-6
EN 60079-6
CSA E60079-6
--------
ISA 60079-6
FM 3621
AS/NZS60079-6
Flammable atmosphere is eliminated
Electric sparks & high temp. possibilities
eliminated
Protection by Immersion
Division 1 or 2
Zone 1 or 2
Encapsulation
m
IEC 60079-18
EN 60079-18
CSA E60079-18
--------
ISA 60079-18
FM 3614
AS/NZS60079-18
Flammable atmosphere is eliminated
Encapsulated apparatus
Division 2
Type ‘n’ Protection
n
IEC 60079-15
EN 60079-15
CSA E60079-15
CSA C22.2 No. 213
ISA 60079-15
-------
AS/NZS60079-15
Non-Sparking apparatus
* Ventilation
v
--------
--------
--------
--------
--------
--------
AS 1482
n Protection includes several methods of ignition
protection
Flammable atmosphere eliminated
Protection by Ventilation
Equipment Certified for Use
Equipment Certified for use in:
Use Appropriately
NEC 500 Class 1, Div. 1
NEC 500 Class 1, Div 2
NEC 505 Class 1, Zone 1
NEC 505 Class 1, Zone 2
OK for use in NEC 505 Class 1, Zone 1 & 2
OK for use in NEC 505 Class 1, Zone 2
NOT OK for use in NEC 500 Class 1, Div. 1
OK for use in NEC 500 Class 1, Div. 2
NEC AEx
NEC AEx
NEC AEx
OK for use in NEC Zone 0, 1 2 as marked
Not suitable for NEC 500 Class 1, Div. 1
Not suitable for NEC 500 Class 1, Div. 2
Zone 1 or 2
IEC Zone 1
IEC Zone 2
Not suitable for any NEC 500 areas
Not suitable for any NEC 500 areas
Division 2
Zone 2
IEC Ex
Not suitable for any NEC / CEC areas
--------
-----
* Only recognised in Australia
Pyroban Ltd UK
Endeavour Works
Dolphin Road, Shoreham-by-Sea
West Sussex, BN43 6QG, UK
Tel: +44 (0) 1273 466200
Fax: +44 (0) 1273 465313
e.mail: info@pyroban.com
Web: www.pyroban.com
protecting people,
their investment and
our environment
NB: The information in this wall chart is for guidance only. For detailed information see the relevant Directives, Regulations and Standards or contact us at info@pyroban.com