Intrinsically Safe (IS) vs. Explosion Proof

You decide your instrument based on the area classification

For Zone 0 , You have to use only intrinsic safe system

For Zone 1, You can use Explosion proof / Intrinsic safety /Increased safety

So if Your instrument is certified for zone 1 it cannot certified for Zone 0

However if your system is certified for Zone 0 , the same can be used for Zone 1

Regards

Jose

Intrinsic safety limits the heat energy of a potential spark to a level below the ignition point of the hazardous substance.

NEMA-7 (gaseous) Explosion proof enclosures contain the force of an explosion, and safely vent the expanding flame while cooling the gases below the ignition point of the hazardous substance.

NEMA-9 (dust) Explosion proof enclosures include sealing flanges that will limit the accumulation of the hazardous substance to prevent ignition.

All different technologies that must be applied per the hazardous rating of the area.

don;t forget to make sure whatever you use has the "UL" logo on it, that's "Underwriters Laboratory". Then you know it rated for whatever zone you need.

Hi there,

Very simply put.

Explosion proof is mechanical protection and cannot be used in Zone 0 (as previously stated)

Intrinsic safety is electrical protection and is the only protection method that can be used in Zone 0

Explosion proof (sometimes known as flame proof in some parts of the world) is used mainly on electrical devices where the energy cannot be limited. Typically this would be electrical motors, stop start stations etc.

Intrinsic safety is used with instrumentation because it would be very difficult to fault find if you cannot have power on the loop.

For more detailed information, do a google search for MTL barriers. They have a wealth of information on their web site about the different protection methods one can employ in the different zones.

Regards,

Craig

Explosion proof must be used in a zone 0 area as lighting, motor power etc are brought into the area using assemblies that are explosion proof housings for any wire junctions that must occur in that area.

So an internal area that is Zone 0 and needs to have lighting would remain unlit if the total banning of explosion proof from a zone 0 area was true

Hi there,

Explosion/Flame proof is definitely not allowed in Zone 0 areas. The only method of protection for Zone 0 is Intrinsic Safe level a.

You need to understand the extent of the zone though. Zone 0 is only a 1 metre sphere of space around the ignition source. So your lighting would more likely than not be placed in Zone 1 or 2.

Please refer to the exact standards for your country. I must re-iterate - The only protection level allowed for Zone 0 is Intrinsic Safe level a Ex(ia).

Regards,

Craig