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EXHAUST FANS AND HOODS Section 15880 15-1207 2.03 ROOFTOP OR SIDEWALL CENTRIFUGAL FAN — UPBLAST — DIRECT DRIVE. A. Roof exhaust fans shall be upblast centrifugal direct drive type. The fan wheel shall be centrifugal backward inclined, constructed of aluminum and shall include a wheel cone carefully matched to the inlet cone for precise running tolerances. Wheels shall be statically and dynamically balanced. B. The fan housing shall be constructed of heavy gauge aluminum with a rigid internal support structure. Windbands shall have a rolled bead for added strength and shall be joined to curb caps with a leak proof continuously welded seam. C. Motors shall be electronically Commutated Motor as follows: 1. Motor enclosures: Open type 2. Motor to be a DC electronic commutation type motor (ECM) specifically designed for fan applications. AC induction type motors are not acceptable. Examples of unacceptable motors are: Shaded Pole, Permanent Split Capacitor (PSC), Split Phase, Capacitor Start and 3 phase induction type motors. 3. Motors are permanently lubricated, heavy duty ball bearing type to match with the fan load and pre -wired to the specific voltage and phase. 4. Internal motor circuitry to convert AC power supplied to the fan to DC power to operate the motor. 5. Motor shall be speed controllable down to 20% of full speed (80% turndown). Speed shall be controlled by either a potentiometer dial mounted at the motor or by a 0-10 VDC signal. 6. Motor shall be a minimum of 85% efficient at all speeds. D. A disconnect switch shall be factory installed and wired from the fan motor to a junction box within the motor compartment. A conduit chase shall be provided through the curb cap to the motor compartment for ease of electrical wiring. E. All fans shall bear the AMCA Certified Ratings Seal for sound and air performance. F. Each fan shall bear a permanently affixed manufacturer's nameplate containing the model number and individual serial number for future identification. G. Provide with the following Options and Accessories: 1. Aluminum Birdscreen 2. Gravity backdraft Dampers 3. UL/cUL 705 Electrical 4. Drain connection 5. NEMA 3R and EXP Disconnect Switches 2.04 ROOF MOUNTED AIR INTAKE/RELIEF HOODS A. Provide hoods, curb mounted, of size noted on drawings and as specified herein. Hood style and manufacturer shall match the centrifugal roof exhausters. B. Bird Screens: Provide removable bird screens, 1/2" mesh, 16 gauge aluminum or brass wire. 3