Rated electrical equipment inside fume hood in a lab

[Sdpaddler50]

Scenario: Lab with typical 6 ft wide, steel, flow hoods where several gals of flam liquids are mixed, dispensed, etc by chemists - we have all seen it before. Steel exhaust duct (most likely 4 in diam) to roof to remove vapors. Exhuast rate within hood to be calculated to ensure LFL < 25%. The hoods i have dealt with before have rated electrical equipment inside them, including the duct and fans if flam vapors are present. Rated electrical is required per IFC, Table 3403.1.1. If the ventilation system has been properly designed, alarmed, etc., has anyone ever seen the the rated electrical requirement to be waived in such an application? I dont believe ventilation in itself is enough to waive the need for rated electrical in such a fume hood, per the IFC but curious what others have to say. Also, i am not finding anything in NFPA 30 which would allow waiving rated electrical due to the exhaust being provided. Thanks, SDpaddler.

 

[DRWeig]

I've never heard of a waiver. The area is classified regardless of ventilation integrity.

Division 2 classification might be attainable if the flammables were not being "...mixed, dispensed, etc., by chemists." Chemists are humans. To err is human. To have an empty can in the lab hood floating on spilled solvent is human too.



Best to you,

Goober Dave

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