AEMT logo
banner 5
Home
Members Database
Membership
Training
Events
Surplus Equipment
Publications & News
Technical Information
Careers
Members' Area
Home > Technical Information > Hazardous Area Equipment 
Hazardous Area Equipment

Zones

Zones   Definitions Category
Atex
Equipment Integrity
Gases and Vapours Dusts   G Gas
D Dust
 
0 20 Explosive atmosphere is present continuously, frequently or for long periods 1G
1D
Safe under normal operation or rare malfunction
1 21 Explosive atmosphere is likely to occur under normal operation 2G
2D
Safe under normal operation or rare malfunction
2 22 Explosive atmosphere may occur under abnormal operation and persist for a short period 3G
3D
Equipment must be safe under normal operation

Protection Concepts

Electrical Symbol Zones Standard Concept
         
Flameproof d 1 and 2  IEC BS EN 60079-1 Contains explosion and flame quenched
 Increased safety  e  1 and 2  IEC BS EN 60079-7  No arcs, sparks or hot surfaces
 Non-Sparking  nA  2  IEC BS EN 60079-15  No arcs, sparks or hot surfaces
 Pressurised  p  1 and 2  IEC BS EN 60079-2  Keep flammable gas out
 Oil immersed  o  1 and 2  IEC BS EN 60079-6  Keep flammable gas out
 Restrictive breathing  nR  2  IEC BS EN 60079-15  Keep flammable gas out
 Simple pressurised  nZ  2  IEC BS EN 60079-15  Keep flammable gas out
 Quartz or sand filled  q  1 and 2  IEC BS EN 60079-5  Contains explosion and flame quenched
 Encapsulation  ma  0,1 and 2  IEC BS EN 60079-18  Keep flammable gas out
 Encapsulation  mb  1 and 2   IEC BS EN 60079-18  Keep flammable gas out
 Enclosed break  nC  2  IEC BS EN 60079-15  Contains explosion and flame quenched
 Energy limiting  nL  2  IEC BS EN 60079-15  Limit spark energy and surface temperatures
 Intrinsic safety  ia  0,1 and 2  IEC BS EN 60079-11  Limit spark energy and surface temperatures
 Intrinsic safety  ib  1 and 2  IEC BS EN 60079-11  Limit spark energy and surface temperatures
 Intrinsic safety  ic  2  IEC BS EN 60079-11  Limit spark energy and surface temperatures
         
Dust        
         
 Enclosure tD  20,21 and 22  IEC BS EN 61241-1  
 Pressurisation pD  21 and 22  IEC BS EN 61241-2  
Encapsulation maD  20,21 and 22  IEC BS EN 61241-18  
Encapsulation mbD  21 and 22  IEC BS EN 61241-18  
Intrinsic safety iaD  20,21 and 22  IEC BS EN 61241-11  
Intrinsic safety ibD  21 and 22  IEC BS EN 61241-11  
         
Mechanical        
         
 Constructional safety  c  0,1,2,20,21 and 22  BS EN 13463-5  
Liquid immersion k  0,1,2,20,21 and 22  BS EN 13463-8  
Pressurisation p  1,2,21 and 22  BS EN 13463-7  
Ignition source control b  0,1,2,20,21 and 22  BS EN 13463-6  
Inherent safety g  0,1,2,20,21 and 22  BS EN 13463-4  
Flow restricting enclosure fr  2 and 22  BS EN 13463-2  
Flameproof enclosure d  1,2,21 and 22  BS EN 13463-3  
         

 

Gas Groups

 

Gas Group Typical Gases
I Methane
IIA

Benzene

Propane

IIB

Ethylene

Hydrogen Sulphide

IIC Hydrogen

Full list of classification can be found in BS EN IEC 60079-20

Temperature Class

Group II

Surface

 

Group I

Mining

Maximum surface temperature °C   Temperature Class Maximum surface temperature °C 
450  T1 450°C without coal dust layer 
300  T2 150°C with coal dust layer 
200  T3  
135  T4  
100  T5  
85  T6  
View upcoming AEMT training courses
Apprentice Schemes
View AEMT upcoming events
Download the AEMT Yearbook
Download AEMT Journals
You are not logged in