<p> ADJUSTABLE PITCH LARGE AEROFOIL</p><p>FAN SPECIFICATION</p><p>The fan will deliver the volume and pressure specified in the schedule of fan duties when tested to AMCA Standard 210-99. The fan will give the sound levels specified in each octave band to within one standard deviation of 3 dB when tested in accordance with AMCA Standard 300-96.</p><p>The fan casing shall be constructed of 3/16” (minimum thickness) mild steel. The motor will be supported by a fabricated steel structure of 3/16” (minimum thickness) mild steel. Drilled flanges will be provided for the attachment of accessories or ductwork.</p><p>The finish of the fan assembly shall consist of high-pressure cleaning, application of one coat of primer and one coat of enamel paint. Dry film thickness (DFT) shall be 2.5 mils minimum.</p><p>The impeller hub will be cast in high strength heat-treated aluminum alloy, precision-machined and balanced. Blades shall be of aerofoil section cast in 12% Silicon aluminum alloy. Hubs and blades are all X-ray examined before machining. </p><p>After assembly the fan is dynamically balanced while on antivibration mountings giving over 90% insulation. The balance standard is in accordance with ISO 2372:1974 Quality Grade C for Class II machines. Maximum vibration velocity will not exceed 0.14 in/sec r.m.s. on 60 Hz supplies over the full pitch angle range, when measured at the fans mounting feet.</p><p>The aerodynamic design of the fan is such that the maximum power absorbed by the impeller occurs with the normal working range, i.e. it has a non-overloading characteristic.</p><p>The impeller is secured to the motor shaft by a key and keyway. Axial location shall be provided by a collar, or a shoulder, on the drive shaft together with a retaining washer and a screw fitted into a tapped hole in the end of the shaft. The screw is locked in position.</p><p>The motor shall have a cast iron frame, pad mounted design and suitable for horizontal through vertical operation. All motors are totally enclosed air over design with a 1.15 service factor. All motor efficiency testing and labeling shall be done in accordance with NEMA MG1-12.53 standard. Insulation shall be Class F with Class B rise. Bearings shall be either ball or cylindrical roller with a L-10 life of 100,000 hours. Grease lubrication lines shall be brought to the outside of the fan casing for motor frame sizes 280 and larger.</p><p>Accessories as scheduled on the submittal sheet.</p>