Class 1, Div 1 vs Class 1, Div 2 motors

[Nchezy]

We designed a mechanical bar screen to be installed in a Wastewater Treatment Facility Headworks Building, which is rated Class 1, Div 1. The bar screen arrived on site, was installed and found to be too tall for the ceiling height. The Contractor and Manufacturer are proposing to replace the motor with a different unit that is shorter and will allow the unit to operate correctly (not hit ceiling). However, the proposed motor is UL Certified for Class 1, Div 2 Groups A,B,C, & D (not Div 1 certified). Based on NFPA 820 the room is rated Class 1, Div 1 because the ventilation is not designed to operate continuously at 12 ACH. Can the Contractor's/Manufacturer's motor proposal be allowed? and would a local code variance be required? Thanks for your thoughts

 

[don_resqcapt19]

No. See 501.125(A) in the 2005 NEC.
Don

 

[bobgorno]

No. Unless you hook the contractor to provide the 12 air changes continuously and can reclassify as Div. 2.