Dust
Pressurization Products
Pressurization is a method of protection used in Class II areas
or Zone 21, 22 Hazardous Locations to prevent the ingress of dust
into electrical enclosures.
Pressurization is generally used for electrical / instrument
enclosures that are too large to be made explosion-proof or too high
powered to use intrinsic safety.
“Good house keeping” is the key to all dust hazard
application where the inside of the enclosure should be clear of dust
before closing the door of the enclosure and applying the
pressure.
A pressure must be maintained within the enclosure to prevent any
ingress of dust. Normally compressed air is used to maintain this
over pressure. Once pressure has been applied the power can then be
switched on.
North American standard for Dust Protection is NFPA 496. Equipment
designed to this concept is suitable for use in Class II, Division 1
or 2 hazardous locations.
IEC and European standards for Dust Protection are IEC/En 61241-0
& 61241-4. Equipment designed to this concept is suitable for use
in Zone 21 or 22 Hazardous Locations.
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