Specifications include, but are not limited to: demolition of individual fume hood exhaust fans and general exhaust fans, and replacement with three chemical exhaust fans connected to a common exhaust header, along with associated structural supports.; HIGH PLUME LAB EXHAUST FAN: A. Manufacturers: Subject to compliance with requirements, provide products by one of the following: 1. Greenheck; 2. Twin City Fan; 3. Cook; B. CORROSION RESISTANT COATING: 1. All steel fan and system components (fan, nozzle, windband and plenum) shall be corrosion resistant coated with a two part electrostatically applied and baked, sustainable, corrosion-resistant coating system.; 2. All parts shall be cleaned and chemically prepared for coating.; 3. The coating system shall not be less than a total thickness of 5 mils, shall not be affected by the UV component of sunlight (does not chalk), and have superior corrosion resistance to acid, alkali, and solvents. Coating system shall exceed 1000 hour ASTM B117 Salt Spray Resistance.; C. FAN HOUSING AND OUTLET: 1. Fan housing to be aerodynamically designed with high-efficiency inlet, engineered to reduce incoming air turbulence.; 2. Fan housing must be manufactured of welded steel or stainless steel.; 3. Fan housing shall be centrifugal involute scroll, allowing all drive components including the motor to be serviced without contact of the contaminated airstream, and manufactured of welded steel.; 4. Discharge nozzle shall be supplied by the fan manufacturer designed to efficiently handle an outlet velocity of up to 7000 FPM.; 5. An integral fan housing drain shall be used to drain rainwater when the fan is deenergized.; D. FAN IMPELLER: 1. Fan impeller shall be centrifugal backward inclined with blades continuously welded to wheel backplate and wheel cone.; 2. The impeller shall be electronically balanced both statically and dynamically in accordance with AMCA Standard 204 to Fan Application Category BV-3, Balance Quality Grade G6.3.; 3. Fan impeller shall be manufactured of aluminum. Impeller shall be coated with a finish to match the fan housing.; 4. Minimum L-10 Bearing Life: 200,000 hours at maximum operating speed, in accordance with ABMA 9 for Ball Bearings, or ABMA 11 for Roller Bearings.; E. FAN MOTOR AND DRIVE: 1. Motors shall be standard NEMA frame, EISA premium efficiency, TEFC enclosure with a 1.15 service factor for across the line operation or 1.0 service factor when used with variable frequency drive (VFD). A factory-mounted NEMA 4X disconnect switch shall be provided for each fan.; 2. Motor shall be inverter duty rated for use with a VFD. Motor shall include a motor manufacturer mounted shaft grounding brush to protect the motor bearings and dissipate voltages and currents built up on motor shaft.; 3. Motor maintenance shall not be required for a period of over 1 year of continuous operation. Calculation of lubrication of motor shall be based on vertical shaft down motor orientation, weight of impeller, running time of 24 hours per day and thrust load created through air movement. Lubrication shall be limited to the motor bearings.; 4. Drive: a. Drive arrangement shall be AMCA arrangement 4, utilizing a tapered bushing connecting the motor shaft to impeller. Belt drive arrangement 9 is not acceptable.; 1) Motor mounting shall be “C-face” and foot mounted for reduced vibration being transferred to the fan housing.; 5. All non-permanently lubricated motors shall have stainless steel braided extended lube lines with zerk fittings.