RATINGS
Met-Pro Corporation Duall Division certifies that the NH/R2B2 type exhaust fans are licensed to bear the AMCA Seal. Ratings are based on tests made in accordance with AMCA Standard 210 and comply with the requirements of the AMCA Certified Ratings Program.

FAN UNITS
Duall type NH Exhaust Fans are of centrifugal design with backward-inclined impeller. Duall type R2B2 Exhaust Fans are of centrifugal design with radial blade impeller. Each fan is complete with coated steel pedestal base, TEFC motor, belt drive, drain, OSHA-approved belt and shaft guards.

CORROSION-RESISTANT CONSTRUCTION
The fan housing, belt guard, and access door are constructed of Type II Grade I PVC, conforming to ASTM D1784-78 and containing no plasticizers, or polypropylene, conforming to ASTM P2146-78. FRP and PVC/FRP construction is also available. All hardware is 316 stainless steel. The drain connection is a 1-1/2" pipe.

NON-OVERLOADING WHEELS
Duall NH fans have non-overloading backward-inclined steel wheels of Class II construction. Duall R2B2 fans have radial blade steel wheels of Class II construction. They are coated with corrosion resistant glass-reinforced vinyl ester resin. The wheels are keyed to steel shafts and are statically and

dynamically balanced, to a maximum of one mil vibration at design speed, utilizing a Model 206 analyzer from Production Measurements Corporation.

BEARINGS AND SHAFT
Duall fans have heavy-duty, grease-lubricated, self-aligning, precision, anti-friction pillow block bearings that have a minimum average life (AFBMA L50) of 100,000 hours. Fan shaft is mild steel, turned, ground, and polished and conforms
to AISI 1045.

DRIVES
Duall provides constant-pitch, V-belt drives with 1.5 service factor. Belts are at minimum size "B", high-capacity type and are provided in matched sets.

MOTORS
Motors are high efficiency totally-enclosed, fan-cooled type operating with 460 volt, 3 phase, 60 hertz electrical power. They are NEMA design B and Class F insulated with 1.15 service factor. Motors are mounted on a slide-rail base.

BASE
Arrangement 9 is provided with the motor factory-mounted on a PVC coated steel pedestal. When Arrangement 1 is required, the fan and motor are factory-mounted on a PVC coated unitary steel base.