Views: 28 Author: Site Editor Publish Time: 2017-05-08 Origin: Site
EQUIPMENT FORMS OF PROTECTION | CENELEC | IEC | NORTH
AMERICAN
STANDARDS | |||||
Protection
Method | Code
of
Protec
tion | Protection
Principle | ATEX
CATEGORY | CENELEC
Standard | IEC
Standard | Code of
Protection | Permitted
in Zone | UL
Stand
ards |
Flameproof | Ex d | Contains the
explosion and
quenches the
flame | 2 | EN 50018 | IEC 60079-1 | AEx d | 1 or 2 | UL 60079-1 |
Intrinsic
Safety | Ex ia | Limit energy
of sparks,
limits the
temperature | 1 | EN 50020 | IEC 60079-11 | AEx ia | 0, 1, 2 | UL 60079-11 |
Ex b | Limit energy
of sparks,
limits the
temperature | 2 | EN 50039 | AEx ib | 1 or 2 | UL 60079-7 | ||
Increase
d Safety | Ex e | No arcs,
sparks or hot
surfaces | 2 | EN 50019 | IEC 60079-7 | AEx e | 1 or 2 | UL 60079-7 |
Encapsulated | Ex m | Keep the flammable
gas away from any hot
surfaces and
ignition
capable
equipment | 2 | EN 50028 | IEC 60079-18 | AEx m | 1 or 2 | UL 60079-18 |
Immersed
in oil | Ex o | 2 | EN 50015 | IEC 60079-6 | AEx o | 1 or 2 | UL 60079-6 | |
Pressurised | Ex p | 2 | EN 50016 | IEC 60079-2 | Ex p | 1 or 2 | NFPA 496 | |
Quartz/Sand
Filled | Ex q | Contains the explosion
and
quenches the
flame | 2 | EN 50017 | IEC 60079-5 | Ex p | 1 or 2 | UL 60079-5 |
Non-Sparking | Ex nA | No arcs,
sparks or hot
surfaces | 3 | EN 50021 | IEC 60079-15 | AEx nA | 2 | UL 60079-15 |
Enclosed
Break | Ex nC | Contains
the explosion
and
quenches the
flame | AEx nC | |||||
Energy
Limitation | Ex nL | Limits
energy of
sparks,
limits the
temperature | AEx nL | |||||
Restricted
Breathing | Ex nR | AEx nR | ||||||
There is a similarity if not a direct equivalent between current IEC and North American Codes of Protection and Area Classification. It is envisaged any differences will be eliminated with the developing acceptance of IEC Standards in North America and vice versa. Here is a simple representative cross relationship between North American and IEC classifications :-
EQUIVALENT ZONE / DIVISION | |
NEC | IEC |
Division I | Zone 0 |
Zone 1 | |
Division II | Zone 2 |
The opposite cannot be assumed. For example Flameproof Ex d equipment certified under IEC rules is not automatically suitable for NEC / CEC Division 1 areas.
