1. Overview of Explosion Protection
1-6
TI 33Q01J30-01E
Type of Protection “n” or Non-Incendive
1) Definition: “Type of protection “n” or Non-Incendive” is the special explosion protection
construction for Zone 2 or Division 2. It is applicable to electric equipments which is not
capable of igniting potentially explosive atmospheres under normal operation.
2) Construction
Energy
restriction
Sealing
F010307.ai
* Under normal operation, it restricts the electric sparks and so on.
• It seals the component that creates sparks.
• It restricts the energy that creates sparks.
• Creepage distance/insulation distance is kept.
• It restricts the surface temperature of electric component.
* The enclosure withstands the shock.
* The enclosure is sealed (BS standard).
Figure Types of Protection “n” or Non-Incendive
Classification by Hazardous Area and Explosive Gas
Classification of Hazardous Area
In the plant which handle flammable gas or vapor, when they are emitted and mixed with air while
at work, “potentially explosive atmospheres” are generated. The area that has a risk of explosion
is called “Hazardous area”.
Zone 0: potentially explosive atmospheres exist continuously or for a long time (at all time)
Zone 1: potentially explosive atmospheres may exist under normal operation of the plant and so
on (sometime)
Zone 2: no potentially explosive atmospheres exist under normal operation of the plant and so
on, or exist briefly if they do (at accidents only)
Table Classification of Hazardous Area
Europe
Australia
U.S.
Canada
Example of usable explosion
protection construction
Zone 0
Division 1
Intrinsic safety (ia)
Zone 1
Division 1
Intrinsic safety (ia)
Flame-proof enclosures, Increased safety
Pressurized apparatus, Oil immersion
Division 2
Intrinsic safety (ib)
Flame-proof enclosures, Increased safety
Pressurized apparatus, Oil immersion
Zone 2
Division 2
Intrinsic safety (ia, ib, ic)
Flame-proof enclosures, Increased safety
Pressurized apparatus, Oil immersion
Type of protection “n”
Non-Incendive
May 18, 2018-00
