Extronics Ltd
Meridian House , Roe Street
Congleton, CW12 1PG, UK.    
Tel:  ++ 44 (0) 1260 297274   
Fax: ++ 44 (0) 1260 297280

 

      Explosion Protection Concepts  

For Europe: CENELEC / ATEX Directive
 
Gas Group
 
Temperature  
Typical material Apparatus group
Max. surface
temperature
T- Class
Classification  
ATEX  
 
Methane
I      Mining          (M1/M2)
 
450C
T1
 
Propane
IIA
 
300C
T2
CE Marking Directive Basic requirements
 
Ethylene
IIB      Surface
 
200C
T3
Low Voltage Directive

Electrical safety of equipment, voltage ranges 50-1000AC, 75-1500 DC

Hydrogen

IC    Applications

 
135C
T4
EMC Directive
Electromagnetic emissions and immunity
 
Acetylene
IIC
 
100C
T5
Machinery Directive
Mechanical and electrical safety
 
All Gases
II
 
85C
T6
Atex Directive
Hazardous Area Equipment (mandatory form 1st July 2003 Currently accepted
      EEx ed IIB T4
II 1G  
**** 4 Digit body number
 
Protection Concepts
Symbol
Zone
Standard
How it works

Category

 
Increased Safety
Ex e
1 & 2
EN 50019
No arcs, sparks or hot surfaces
2
 
Non-sparking
Ex nA
2
EN 50021
3
 
Flameproof
Ex d
1 & 2
EN 50018
Contain the explosion and quench flame
2
 
Enclosed Break
Ex nW
2
EN 50021
3
 
Quartz/Sand Filled
Ex q
1 & 2
EN 50017
2
 
Intrinsic Safety
  Ex ia  
Ex ib
0,1 & 2
1 & 2
EN 50020
EN 50039
Limit energy of sparks; limit the temperature
1
 
2
 
3
 
Energy Limitation
Ex nL
2
EN 50021
 
Pressurised
Ex p
1 & 2
EN 50016
Keep the flammable gas away from any hot surfaces and ignition Capable equipment
 

2

 
Simplified Pressurisation
Ex nP
2
EN 50021
3
 
Encapsulation
Ex m
1 & 2
EN 50028
2
 
Oil Immersion
Ex o
1 & 2
EN 50015
2
 
Restricted breathing
Ex nR
2
EN 50021
3
 
Special
Ex s
0*,1&2
EHSR (ATEX)
Any Proven Method
1,2&3
   
* Label must indicate Zone 0
 
Classification Criteria For Zone

ATEX Marking

Zone 0 Flammable material always present or for long periods (e.g.1000 hours or more per year) G Category 1 Equipment
Zone 20 D
Zone 1 Flammable material present in normal operation (e.g. 10-1000 hours/year) G Category 2 Equipment
Zone 21 D
Zone 2 Flammable material present for short periods only (e.g. less than 10 hours/year) G Category 3 Equipment
Zone 22 D
For North America
PROTECTION METHODS

INTRINSICALLY SAFE
Ex ia IIC T4
(Method of protection)

Class I, Division 1
(Area Classification)

Groups A, B, C and D
(Gas Grouping)

T4
(Temperature Code)
 
North America

Method of
Protection
Division
Intrinsic Safety
1 or 2
Explosion-Proof
1 or 2
Pressurization
1 or 2
Non-Incendive Circuits
2
*Specifically Assessed
Equipment
North America, CENELEC (Europe) and IEC (International)
Method of Protection
Zone
Code Letter
CENELEC/IEC
Intrinsic Safety
0, 1 or 2
ia
1 or 2
ib
Flame-Proof
1 or 2
d
Pressurization
1 or 2
p
Increased Safety
1 or 2
e
(*No excessive Heat Generating Devices or Ignition-capable Arcing / Sparking Devices)
 
AREA CLASSIFICATION
 
 
CONTINUOUS
HAZARD
INTERMITTENT
HAZARD
HAZARD UNDER
ABNORMAL CONDITIONS
NORTH AMERICA
(CEC/NEC)
Division 1
Division 2
or Zone 2
Zone 0
Zone 1
CENELEC/IEC
Zone 0
Zone 1
Zone 2
 
 
HAZARDOUS LOCATIONS GAS GROUPS
 
TYPICAL
GAS HAZARD
NORTH AMERICA
CEC SECTION 18, NEC ARTICLE 500
CENELEC/IEC
CENELEC, EN 50014,
IEC 79-0
ACETYLENE
A or IIC
IIC
HYDROGEN
B or IIC
IIC
ETHYLENE
C or IIB
IIB
PROPANE
D or IIA
IIA
METHANE
Group D (gaseous mines) or I
I
 
 
TEMPERATURE CODE/CLASS
 
MAXIMUM SURFACE TEMPERATURE (C)
450
300
280  260  230  215
200  
180 165  160
135 
120
100
85
NORTH AMERICA
Temp Code
T1
T2
T2A  T2B  T2C  T2D
T3   
T3A T3B T3C
T4 
T4A
T5
T6
CENELEC/IEC
Temp Class
T1
T2
T3
T4
T5
T6
 
Extronics Limited
Meridian House, Roe Street, Congleton, CW12 1PG, UK.    
Tel:  ++ 44 (0) 1260 297274     Fax: ++ 44 (0) 1260 297274
 info@extronics.com

This information has been kindly supplied by Epsilon Technical Services Ltd

info@epsilon-ltd.com