Division 23 - HVAC Section Switzerland Beallsville K-12 DEDICATED OUTSIDE AIR HANDLING UNIT WITH DESSICANT WHEEL

Transcription

1 SECTION DEDICATED OUTSIDE AIR HANDLING UNIT WITH DESSICANT WHEEL PART 1 - GENERAL 1.1 RELATED DOCUMENTS A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 01 Specification Sections, apply to this Section. 1.2 SUMMARY A. Section Includes: 1. Constant volume indoor air handling unit with desiccant wheel rated for 100% outside air. 1.3 PERFORMANCE REQUIREMENTS A. Structural Performance: Casing panels shall be self-supporting and capable of withstanding 133 percent of internal static pressures indicated, without panel joints exceeding a deflection of L/240 where "L" is the unsupported span length within completed casings. 1.4 SUBMITTALS A. Product Data: For each air-handling unit indicated. 1. Unit dimensions and weight. 2. Cabinet material, metal thickness, finishes, insulation, and accessories 3. Fans: a. Certified fan-performance curves with system operating conditions indicated. Fan curves shall include at a minimum: system curve, bhp, rpm, operating point, surge point, and maximum wheel rpm. b. Certified fan-sound power ratings. c. Fan construction and accessories. d. Motor ratings, electrical characteristics, and motor accessories. 4. Certified coil-performance ratings with system operating conditions indicated. 5. Certified desiccant heat recovery wheel performance ratings with system operating conditions indicated. 6. Dampers, including housings, linkages, and operators. 7. Filters with performance characteristics. B. LEED Submittals: 1. Product Data for Credit EQ 3.1, "Construction IAQ Management Plan": Replacement filtration media for occupancy. C. Operation and Maintenance Data: For air-handling units to include in emergency, operation, and maintenance manuals. Include instructions for lubrication, filter replacement, motor and drive replacement, spare parts lists, and wiring diagrams. 1.5 QUALITY ASSURANCE A. Manufacturers: Equipment manufacturers listed under section 2.1 Acceptable Manufacturers will be deemed acceptable if equipment meets the scheduled and specified performance levels and complies with all of the items in this specification. The intent of this specification requirement is to assure that the products are delivered through a quality system and framework that will assure consistent quality. If the

2 equipment is provided by one of the acceptable manufacturers, other than basis of design, then the Heating Contractor shall be responsible for coordinating with the General Contractor and all affected Subcontractors to ensure proper provisions for installation of the furnished unit. This coordination shall include, but not be limited to, the following. 1. Structural supports for units. 2. Piping size and connection/header locations. 3. Electrical power requirements and wire/conduit and over current protection sizes. 4. The Heating Contractor shall be responsible for all costs incurred by the General Contractor, Subcontractors, and Consultants to modify the building provisions to accept the furnished units. B. Electrical Components, Devices, and Accessories: Listed and labeled as defined in NFPA 70, by a qualified testing agency, and marked for intended location and application. C. NFPA Compliance: Comply with NFPA 90A for design, fabrication, and installation of air-handling units and components. D. ARI Certification: Air-handling units and their components shall be factory tested according to ARI 430, "Central-Station Air-Handling Units," and shall be listed and labeled by ARI. E. Comply with NFPA REFERENCES A. AMCA 99 Standard Handbook. B. AMCA 210 Laboratory Methods of Testing Fans for Rating Purposes. C. AMCA 300 Test Code for Sound Rating Air Moving Devices. D. AMCA 301 Method of Publishing Sound Ratings for Air Moving Devices. E. AMCA 500 Test Methods for Louvers, Dampers, and Shutters. F. ANSI/AFBMA 9 Load Ratings and Fatigue Life for Ball Bearings. G. ANSI/UL 900 Test Performance of Air Filter Units. H. ARI 410 Forced-Circulation Air Cooling and Air Heating Coils. I. ARI 430 Standard for Application of Central-Station Air Handling Units. J. ARI 260 Sound Rating of Ducted Air Moving and Conditioning Equipment. K. NFPA 90A Installation of Air Conditioning and Ventilation Systems. L. SMACNA Low Pressure Duct Construction Standards. M. AMCA Methods of Testing Airflow Measurement Stations for Rating. N. ASHRAE 15 Safety Standard for Refrigeration Systems O. ASHRAE 52.1/52.2 Method of Testing General Ventilation Air Cleaning Devices for Removal Efficiency Particle Size. P. ASHRAE 62 Ventilation for Acceptable Indoor Air Quality. Q. ASHRAE 68--Laboratory Method of Testing to Determine the Sound Power in a Duct

3 R. ASHRAE 90.1 Energy Standard for Buildings Except Low-Rise Residential Buildings. 1.7 COORDINATION A. Coordinate sizes and locations of concrete bases with actual equipment provided. B. Coordinate sizes and locations of structural-steel support members, if any, with actual equipment provided. C. Coordinate sizes and locations of duct connections with installing contractor prior to fabrication of equipment. 1.8 DELIVERY, STORAGE AND HANDLING A. All handling and storage procedures shall be per manufacturer's recommendations. B. Units shall be shrink-wrapped by the manufacturer prior to shipment to prevent damage due to weather and road debris during transportation and thereafter while in storage awaiting installation. Units not factory shrink-wrapped must be provided with tarps that cover the entire unit. The tarps must be turned over to the contractor once the units arrive at the jobsite / riggers yard. The contractor will then be required to cover each segment / unit until it is installed. Protection of the complete unit for avoidance of general rusting must be handled as best suits the circumstances. Store in a place protected from construction traffic and handle carefully to avoid damage to components, enclosures, and finish. C. All openings shall be protected against damage from shipping. D. Safety warning labels shall be clearly marked in English. E. Filters shall ship loose from factory with unit. F. All loose-shipped items need to be packed, protected and secured with the air units. G. Motors should be protected and inspected in accordance with the manufacturer's specific instructions regarding periods of long storage 1.9 WARRANTY A. The manufacturer's standard warranty shall be for a period of thirty (30) months from the date of shipment. Warranty is limited to manufacturers defect only. The warranty shall include parts during this period. The warranty shall not include parts associated with routine maintenance, such as belts, air filters, etc. Warranty is not extended to any alteration, modifications or external component attached to the original equipment as built and shipped from manufacturing facilities. B. The desiccant wheel and energy recovery wheel shall be provided with a five year parts warranty. C. Contractor standard warranty shall include all labor for a period no less than twelve (12) months from the date of final commissioning EXTRA MATERIALS A. Furnish extra materials that match products installed and that are packaged with protective covering for storage and identified with labels describing contents. 1. Filters: One set for each air-handling unit (in addition to set installed at Owner acceptance). 2. Fan Belts: One sets for each air-handling unit fan

4 PART 2-PRODUCTS 2.1 MANUFACTURERS A. Manufacturers: Subject to compliance with requirements, provide products by: 1. AnnexAir. 2. DesChamps 3. Semco 4. Venmar 5. McQuay International 2.2 GENERAL DESCRIPTION A. Factory manufactured air-handling units designed to the performance levels specified with a combination of air-handling components in unitized housings to form complete, integrated machines as indicated on the drawings. B. Fabricate air-handling units suitable for the scheduled capacities. C. Factory test and balance fan design and drives to limit vibration (displacement in mils) at operating speeds. D. Base performance on sea level conditions. E. All internal components specified in the air handling unit schedule shall be factory furnished and installed. Units shall be completely factory assembled. F. Units shall ship in one (1) piece whenever possible. Unit shipping splits shall be provided where necessary for shipping or specified by customer. Lifting lugs shall be supplied on each side of a shipping split and at all unit corners to facilitate rigging and aid in joining shipping sections. Lifting lugs to be suitable for rigging without requiring additional support frames. The contractor will be responsible for any reassembly required with units that ship in multiple pieces. 2.3 FRAME CONSTRUCTION A. Unit base construction shall be welded construction with all joints coated for corrosion resistance. Perimeter channels shall be 8 inches tall. Intermediate channels shall be incorporated as required to support components and floor surfaces. B. Unit base shall be constructed of structural steel members, hot dip galvanized or prime and finish painted, welded in a grid to support the unit enclosure and internal components. The entire floor of unit to be constructed of galvanized steel with 4" of 3 lb density fiberglass insulation located under floor. C. Heavy duty lifting brackets for eight (8) point lift shall be provided on unit base frame for rigging unit into place. D. The entire framework and structure of the unit shall be heavy gauge galvanized steel. E. Units shall be with arrangements as shown on the Drawings. F. Floor panels shall be 4" double wall construction, of a minimum of 16 gauge galvanized steel. Provide 3/16" aluminum treadplate floor. All floors shall be fully welded to the base support structure. All floor seams shall be welded. G. All openings in the floor shall be framed by a collar, which extends 2" above the wearing surface. Floor sheets shall be welded to all perimeter and intermediate base frame members. Floor wearing surface

5 shall be 14 gauge checker plate, or lesser gauge steel provided added reinforcement maintains midreinforcement deflection to less than 1/4" when subjected to a 200 pound load distributed over 80 square inches. Insulation shall be retained by a 22 gauge galvanized steel underliner. All underliners shall be stitch welded and continuously sealed with rubber butyl sealant. Floor drains shall be provided in outside air intake section and cooling coil section. H. When required for shipping or for job installation requirements the unit(s) shall be split into sections as indicated on the Contract Documents. Splits shall be framed with hot rolled structural angle to ensure structural rigidity. Manufacturer shall supply rubberized closed cell gasketing, caulk, and touch-up paint. 2.4 CASING CONSTRUCTION A. Casing shall be double wall construction. Exterior panels shall be minimum of 16 gauge galvanized steel. The interior panels shall be minimum 18 gauge galvanized steel and 24 gauge perforated galvanized steel where required. Provide electrolytic isolation where dissimilar metals would come in contact. B. All panels shall be individually gasketed and completely removable from the frame, each independent of each other. Panels shall use "C" channel edge design. C. Access doors shall be insulated double wall fully welded and provided with butyl rubber sealant. Door frame shall be fabricated of brake formed angle of material similar to unit exterior wall. Frame shall be fitted with a continuous neoprene bulb gasket, door thickness shall be 2 inches. Doors shall be 24" wide by 69" high, unless unit size dictates a smaller door, incorporated in all sections requiring servicing, refer to drawings for additional access doors. Doors shall be furnished with two 6" long stainless steel butt hinges welded to door and frame, furnish each door with (two minimum) handles and neoprene gasketing. Provide double pane viewing window in each access door. D. Access doors to be labeled with laminated plastic (1/16" thick) black background with 2" white letters. E. All fasteners on the exterior of the unit to be corrosion resistant. F. The air-handling unit shall be completely insulated throughout all panels and structural frame members with spray injected foam or 2" 3lb density fiberglass insulation to thoroughly insulate and seal the air unit structure. Openings in structural channels shall be covered. Fiberglass insulation shall be adhered to panels and bottom side of floor before assembly. Provide a vapor barrier on underside of unit. G. The finish for the unit shall include a painted exterior over galvanized steel having a minimum A-60 application. H. Condensate Drain Pans: 1. Drain pan design and application shall comply fully with the stated intent of ASHRAE Fabricated with slopes in at least 2 planes to collect condensate from cooling coils (including coil piping connections, coil headers and return bends, and a minimum of 6 inches downstream from cooling-coil face. 3. Formed sections. 4. Double-wall, stainless steel sheet with space between walls filled with foam insulation and moisture-tight seal. 5. A minimum of 2 inches deep, and complying with requirements in ASHRAE Drain Connections: Both ends of pan with NPS 1.25 threaded nipple. 7. Pan-Top Surface Coating: Asphaltic waterproofing compound if drain pan is not welded. 8. Units with stacked coils shall have an intermediate drain pans to collect condensate from each coil

6 I. Access sections shall be equipped with access doors. Access sections shall be placed between coil sections to allow access for cleaning and repair. 2.5 FAN, DRIVE, AND MOTOR SECTION A. Fans shall be of the Class and Type as scheduled, selected to provide the airflow and pressure specified. B. Fan segments shall be equipped with single width single inlet (SWSI) plenum fans as scheduled. Single width single inlet fan (SWSI) shall have airfoil (AF) blades. Wheels shall have a spun non-tapered style blade retaining ring on the inlet side to allow higher efficiencies over the performance range of the fan. The wheels shall be non-overloading type. The blades shall be securely welded, die-formed backward curved (16" and smaller) or airfoil (18" and larger) type. All wheels shall be statically and dynamically balanced on precision electronic balancers to a level of G6.3 (per ANSI 2-19) or better. C. All airfoil fans shall bear the AMCA Seal. Airfoil fan performance shall be based on tests made in accordance with AMCA standards 210 and comply with the requirements of the AMCA certified ratings program for air and sound. In addition, all airfoil wheels shall comply with AMCA standard and D. Fans shall have polished steel shafts sized so the first critical speed is at least 25% over the maximum operating speed for each pressure class. Close tolerances shall be maintained where the shaft makes contact with the bearing. Shaft shall be factory coated after assembly with an anti-corrosion coating. Bearings shall be heavy duty, grease lubricated, antifriction ball or roller, self-aligning, pillow block type and selected for a minimum average bearing life (AFBMA L-50) in excess of 200,000 hours at the maximum fan RPM. All bearings shall be equipped with re-greasable zerk fittings and, where necessary, extended lube lines for easy access for re-lubrication. E. After the pre-balanced fan is installed on the fan skid and isolator rails, the entire fan skid shall be runbalanced at the specified speed to insure smooth and trouble-free operation. The run balance shall include filter-in and filter-out balancing in all three (3) planes, on both sides of the fan assembly at the bearings. 1. Filter-in measurements shall be taken in the horizontal and vertical planes on the drive and opposite-drive sides of the fan shaft. 2. Filter-out measurements shall be taken in the horizontal, vertical and axial planes on the drive and opposite-drive side of the fan shaft. F. The fan motor and fan-assembly shall be internally mounted on a common base to allow consistent belt tension with no relative motion between the fan and motor shafts. The common base shall be isolated on a full width isolator support channel using 2" deflection. 1. The fan motor shall be on an adjustable base. 2. Fan segment shall be equipped with an access door. 3. A fan inlet screen shall be provided on all fans. 4. SWSI Plenum fans shall be provided with a fan cage. 5. OSHA approved belt guards shall be provided on all fans. 6. Fan assemblies shall be balanced for inverter duty operation. 7. The fan will be balanced over the entire range of fan operation (30% to 100% of RPM). 8. VAV units to be factory inverter balanced. G. Fans shall be selected so as not to operate beyond the manufacturer's published surge point at the design conditions. Surge points shall be clearly indicated on submittals

7 2.6 COIL SECTION A. Coil segment length shall be optimized to contain the selected coils. Coils shall be selected to maximize unit tunnel area using single or stacked coil arrangements as needed to satisfy required coil face areas. 1. All cooling and/or heating coils shall be furnished to meet the performance requirements set forth in the schedule. 2. All water coils shall have performance certified in accordance with ARI Standard 410 for coil capacity and pressure drop. 3. All coils must be circuited to operate at design load with water velocity within the ARI range of certified rating conditions. 4. Coil segment side and/or top panels shall be removable to allow for removal and replacement of coils, without affecting the structural integrity of the unit. 5. Coil segment shall accommodate full-face height or reduced face height coils, as specified. B. Cooling Coil Segment shall be provided with a full width, double wall, multi-sloped (IAQ) stainless steel drain pan that extends downstream a minimum 12" beyond the last coil in the section to catch any possible condensate carryover and to provide drain pan access for cleaning and inspection. The drain pan shall be insulated with spray-injected foam to completely seal the drain pan assembly. C. All coils shall be slide out, shipping type, mounted on tracks, and easily removable from the air-handling unit by removing only one exterior panel. Coils that require additional disassembly of the unit or replacement of the entire coil section for coil removal are unacceptable. D. Coils shall be supported by coil support members (galvanized steel for heating coils and stainless steel for cooling coil), constructed of channeled members, allowing uninhibited access for inspection and safe cleaning. E. All heating and cooling coils shall be 5/8" OD, TWT, Al fin construction. Heating coil shall be furnished with galvanized casings and cooling coil shall be furnished with stainless steel casings. Provide stainless steel drain pans in cooling coil segments. F. All vertical coil supporting members (bulkheads) and block offs shall be constructed of stainless steel and shall entirely seal off the coil, preventing air bypass. G. Coil grommets shall be provided on all coils to completely seal the area between the coil connection and the unit casing. H. Drainable Water coils shall be designed to operate at 250-psig design working pressure and up to 300 F and shall be tested with 325-psig compressed air under water. Circuiting shall provide free and complete draining and venting when installed in the unit. All vent and drain connections shall be extended to the outside of the unit casing. I. The primary surface shall be copper tube, staggered in direction of airflow. Tubes shall be mandrel expanded to form fin bond and provide burnished, work-hardened interior surface. J. Extended surface shall consist of die-formed, continuous, aluminum corrugated enhanced performance fins. The fins shall have fully drawn collars to accurately space fins, and to form a protective sheath for the primary surface. K. Coils with finned height greater than 48 inches shall have an intermediate drain pan extending the entire finned length of the coil. Cooling coils in excess of 48 inches in height shall not be acceptable unless provided with an intermediate drain pan. The intermediate pans shall have down spouts to guide condensate to the main drain pan. L. Cooling coil casing shall be constructed of stainless steel (galvanized steel for heating coil casings). Tube sheets on each end shall have drawn collars to support tubes. A single intermediate coil support

8 shall be provided on coils with a finned length of more than 62 inches, two (2) intermediate supports above 100 inches in length, and three (3) intermediate supports on coils with a finned length of more than 141 inches. Casing channels shall be free draining, without depressions to collect moisture and contaminants. Casing channels shall not block fin area. M. Headers shall be of heavy seamless copper tubing, silver-brazed to tubes. Connections shall be of steel, with male pipe threads, silver-brazed to the headers. A 1/4" FPT, plugged vent or drain tap shall be provided on each connection. All vent and drain connections shall be extended to the outside of the unit casing. N. Circuiting shall be to provide free draining and venting, through one vent and one drain on each coil, when installed with casing level. Coils shall be circuited, and have connections arranged, for counter flow of air and water with supply on bottom and return on top of coil headers. Coil circuiting shall provide for design water velocity in tubes without exceeding total water pressure drops in schedule. O. Coils using turbulators are unacceptable. P. The cooling coil segment interior, floor, and roof walls shall be constructed of galvanized steel to help prevent long term corrosion due to the high content of moisture in the air following the cooling coil. Q. The maximum face velocity for the air moving across the cooling & heating coil shall not exceed 500 feet per minute. 2.7 AIR FILTRATION SECTION A. Filters and filter segments shall be provided as scheduled. Filter tracks shall be constructed of galvanized steel and be built as an integral part of the unit. Filter media shall be listed Class 2 or Class 1 under U.L. Standard 900 as required by local codes. B. Filter media shall be as listed below. 1. 2" pleated MERV " pleated MERV 13. C. A Magnahelic filter gage shall be provided across each filter bank. D. The maximum face velocity across the filters may not exceed 550 feet per minute. 2.8 CONTROL DAMPERS A. Dampers shall be of ultra-low leak design having airfoil blades. The damper blades shall be provided with extruded vinyl edge seals and flexible metal compressible jamb seals. Outside air and return air dampers shall have leakage not exceeding 4 CFM/square foot at 1" w.g., complying fully with the requirements of ASHRAE All damper blades shall be opposed acting with the exception of the return air damper; this damper shall be parallel acting and shall be aimed to direct the return air towards the outside air damper. Dampers shall be equal to Ruskin CD-60. The outside air and outside air bypass damper shall be equal to Ruskin CD-50 (manufactured of aluminum). Dampers shall be furnished with two-position electric actuators with an integral limit switch. Refer to Air Duct Accessories section for acceptable manufacturers of dampers. 2.9 AIR-TO-AIR DESICCANT WHEEL A. Desiccant wheel casing to match overall unit casing as described above. B. The desiccant wheel media shall be a monolithic, extended-surface contact medium, fabricated entirely of inert, inorganic binders and glass fibers formed into narrow passages in the direction of airflow. The wheel shall be non-toxic. The process and reactivation air streams shall be separated by air seals and

9 internal by air seals and internal partitions so that the humid reactivation air does not mix with the dry process air. C. Wheel Face Seals: The dehumidifier shall have full-face seals on both the process air entering and the process air leaving sides of the wheel. These shall seal the entire perimeter of both air streams as they enter and leave the wheel. Partial seals shall not be acceptable. The seals shall be the silicone rubber bulb-type, with a protective strip of low-friction, abrasive-resistant surface to extend seal life and reduce the force needed to turn the desiccant wheel. The seals shall be documented to have a minimum working life of 25,000 hours of normal operation. D. Purge Sector: The unit shall be provided with a factory set, field adjustable purge sector designed to limit cross contamination to less than.04 percent of that of the exhaust airstream concentration when operated under appropriate conditions. E. Materials: The glass fibers which form the support matrix shall be made from uniform continuous strands larger than five microns in diameter which are non-respirable and are not considered a possible health risk by the International Agency for Research on Cancer (IARC). F. Flame spread and smoke generation: The wheel shall be tested according to ASTM E84-90 and shall achieve the following results: 1. Flame spread index = Smoke developed index = 10. G. Desiccant impregnation: The desiccant shall be evenly impregnated throughout the structure for predictable, consistent performance and for maximum wheel life. H. Desiccant type: The desiccant material used in wheels shall be Type III Brunauer isotherm desiccant. The desiccant impregnated into the contact medium shall be a titanium-reinforced silica gel. The desiccant wheel shall be a fabricated extended surface contact media with a multitude of small passages parallel to the airflow. The rotary structure shall be a monolithic composite consisting of inter silicates with D2 microscopic pores designed to remove water in a vapor phase. The desiccant shall be hydrothermally stabilized silica gel reinforced with titanium for maximum strength and stability over time. The fabricated structure shall be smooth and continuous having a depth of between 125 and 200 millimeters in the direction of airflow without interruptions or sandwich layers which restrict airflow or create a leakage path at joining surfaces. Nominal face velocity shall not exceed 1000 fpm. The manufacturer shall provide documentation to establish that: 1. The desiccant retains more than 90% of its original capacity after ten years of continuous operation in clean air, with inlet air conditions up to and including 100% relative humidity. 2. The wheel as impregnated with silica gel is capable of withstanding five complete water immersion cleaning cycles while retaining more than 95% of its original adsorption capacity. I. Desiccant wheel support and drive assembly: Desiccant wheels 60" in diameter and smaller shall be a single piece for fast removal and simple handling. Belt-driven desiccant wheels shall be supported by four rollers at the base of the unit so the wheel can be easily removed by lifting it over the rollers using the drive belt. In addition, the wheel drive assembly shall provide: 1. Rotation speed: To avoid excessive heat carryover from reactivation to the process air, the wheel rotation speed shall not exceed 8 rph while achieving the required moisture removal rate at the specified conditions. 2. Drive belt: Units with compressor capacity less than 25 nominal tons shall use a belt-driven wheel. Units with compressor capacities greater than 25 tons shall use direct-drive wheels. 3. Drive motor: The drive motor shall be fractional horsepower and rated for continuous duty for a period of 20,000 hours under the load conditions imposed by the drive assembly

10 4. Rotation detection: The drive assembly shall be equipped with a rotation detection circuit which shuts down the dehumidifier and signals the Building Automation Controls through an alarm if the wheel is not rotating. J. Manufacturer shall include desiccant wheel interface with BAS system for control, monitoring, and alarms as described in Division 23 Sections "Instrumentation and Control for HVAC" and "Sequence of Operations for HVAC Controls." 2.10 AIR-TO-AIR ENERGY RECOVERY A. Manufacturers: Subject to compliance with requirements, provide products by one of the following: 1. SEMCO Incorporated. 2. Thermotech 3. Innergy Tech B. Casing: 1. Wheel casing to match overall unit casing as described above. 2. Integral purge section limiting carryover of exhaust air to between 0.05 percent at 1.6-inch wg and 0.20 percent at 4-inch wg differential pressure. 3. Casing seals on periphery of rotor, on duct divider, and on purge section. 4. Support rotor on grease-lubricated ball bearings with extended grease fittings. Mount horizontal wheels on tapered roller bearing. C. Rotor: Polymer segmented wheel, strengthened with radial spokes impregnated with non-migrating, water-selective, molecular-sieve desiccant coating. Construct media for passing maximum 800- micrometer solids. 1. The rotor media shall be made of aluminum which is coated to prohibit corrosion. All media surfaces shall be coated with a non-migrating solid adsorbent layer prior to being formed into the honeycomb media structure to insure that all surfaces are coated and that adequate latent capacity is provided. The media shall have a flame spread of less than 25 and a smoke developed of less than 50 when rated in accordance with ASTM E87. In addition to the desiccant coating that is applied to the surfaces of the aluminum substrate, the two faces of the total energy recovery wheel shall be covered and sealed with a two part polymer heavy duty coating specifically developed for the selective adsorption of water vapor. The desiccant shall utilize a 3A molecular sieve certified by the manufacturer to have an internal pore diameter distribution which limits adsorption to materials not larger than the critical diameter of a water molecule (2.8 angstroms). Submit certification by a qualified independent organization documenting equal sensible and latent efficiencies conducted in accordance with ASHRAE 84-78P and the results presented in accordance with ARI 1060 standards. An independent wheel test from a credible test laboratory shall document that the desiccant material utilized does not transfer pollutants typically encountered in the indoor air environment. The cross-contamination and performance certification reports shall be provided with the submittal package. 2. Wheels greater than 30 inches in diameter shall be provided with removable energy transfer matrix. Wheel frame construction shall be welded hum, spoke and rim assembly of stainless, plated and/or coated steel and shall be self-supporting without matrix segments in place. Segments shall be removable without the use of tools to facilitate maintenance and cleaning. Wheel bearings shall be selected to provide an L-10 life in excess of 200,000 hours. Rims shall be continuous rolled stainless steel. Wheels larger than 30 inches in diameter shall be connected to the shaft by means of taper lock hums

11 3. All diameter and perimeter seals shall be provided as part of the cassette assembly and shall be factory set. Drive belt(s) of stretch urethane shall be provided for wheel rim drive without the need for external tensioners or adjustment. 4. The energy recovery cassette shall be an Underwriters Laboratories Recognized Component for electrical and fire safety. The wheel drive motor shall be an ULRC and shall be mounted in the cassette frame and supplied with a service connector or junction box. Thermal performance shall be certified by the manufacturer in accordance with ASHRAE Standard , Method of Testing Air-to-Air Exchangers and ARI Standard , Rating Air-to-Air Heat Exchangers For Energy Recovery Ventilation Equipment. Cassettes shall be listed in the ARI Certified Products Directory and bear the ARI Certified Product Seal. D. Drive: Fractional horsepower motor and gear reducer, with speed changed by variable frequency controller, and self-adjusting multilink belt around outside of rotor. E. Purge Sector: The unit shall be provided with a factory set, field adjustable purge sector designed to limit cross contamination to less than.04 percent of that of the exhaust airstream concentration when operated under appropriate conditions. F. Controls: 1. Starting relay, factory mounted and wired, and manual motor starter for field wiring. 2. Variable frequency controller, factory mounted and wired for control of both Enthalpy and Passive type wheels shall be accomplished by the use of an A/C inverter. The inverter shall include all digital programming with a manual speed adjustment on the front of the inverter. The drive system shall allow for a turndown ratio of 80:1 (20 rpm to 1/4 rpm). 3. Pilot-Light Indicator: Display rotor rotation and speed. 4. Speed Settings: Adjustable settings for maximum and minimum rotor speed limits. 5. Manufacturer shall include energy wheel interface with BAS system for control, monitoring, and alarms as described in Division 23 Sections "Instrumentation and Control for HVAC" and "Sequence of Operations for HVAC Controls." 2.11 APPURTENANCES A. Access segment shall be supplied between the heating and cooling coil segments to allow access to clean/maintain coils ELECTRICAL CHARACTERISTICS A. Fan motors shall be furnished in sizes, electrical power and starting characteristics as shown in the schedule. 1. All fan motors will be built in accordance with the latest standards of the National Electrical Manufacturer's Association (NEMA) and IEEE and shall be rated for continuous duty at full load at 40 C ambient temperature rise and a service factor of Fan motors shall be NEMA design ball bearing type. 3. Fan motors shall be 1750 RPM, open drip proof. 4. All fan motors shall be premium efficiency. 5. Motors shall be suitable for use in variable frequency application, per NEMA MG-1 Part 30. B. Each unit shall include a single 480 volt (as scheduled), 3 phase, 60 cycle power connection at the unit's main electrical panel. The electrical panel shall be NEMA 12 rated and mounted on the unit exterior.. The electric panel shall consist of a non-fused disconnect, variable frequency drives for each

12 fan and wheel, control power transformer, and HOA switch for the unit. Electrical panels shall bear an ETL label. C. All wiring 120 volt and higher and wire size #8 and smaller shall be run in MC cable. All wire size #6 and larger shall be run in EMT. Fan motors requiring wire run in EMT shall have a 2' length of sealtight at the motor junction box. Low voltage wiring shall use plenum cable, installed external to the conduit. Starter coils shall be 24 volt AC for contactors rated 75 amps or less and 120 volt AC for contactors rated greater than 75 amps. D. Each unit shall include a single 115 volt(as scheduled), 1 phase, 60 cycle power connection at the unit's main electrical panel as an independent power source for lights and the convience outlets, having one switch for light control that is externally mounted, separate from the Motor power source entrance. Lighting circuit shall receive power from a "Dedicated Circuit Breaker' remotely provided by Electrical Contractor. E. Vapor tight lights shall be provided in access compartments as shown on the General Arrangement drawing. Lights shall be wired to a single switch on the unit exterior. A GFI receptacle shall be mounted next to the light switch on each fan section CONTROLS A. Control devices and operational sequences are specified in Division 23 Sections "Instrumentation and Control for HVAC" and "Sequence of Operations for HVAC Controls." 2.14 SOURCE QUALITY CONTROL A. Fan Sound-Power Level Ratings: Comply with AMCA 301, "Methods for Calculating Fan Sound Ratings from Laboratory Test Data." Test fans according to AMCA 300, "Reverberant Room Method for Sound Testing of Fans." Fans shall bear AMCA-certified sound ratings seal. B. Fan Performance Rating: Factory test fan performance for airflow, pressure, power, air density, rotation speed, and efficiency. Rate performance according to AMCA 210, "Laboratory Methods of Testing Fans for Aerodynamic Performance Rating." C. Water Coils: Factory tested to 300 psig according to ARI 410 and ASH RAE 33. PART 3 - EXECUTION 3.1 INSTALLATION A. Equipment Mounting: Install air-handling units on concrete bases using elastomeric pads. Secure units to anchor bolts installed in concrete bases. Comply with requirements for concrete bases specified in Division 03 Section "Cast-in-Place Concrete". Comply with requirements for vibration isolation devices specified in Division 23 Section "Vibration Controls for HVAC Piping and Equipment." 1. Minimum Deflection: 1 inch. 2. Install galvanized steel plate to equally distribute weight over elastomeric pad. 3. Install dowel rods to connect concrete base to concrete floor. Unless otherwise indicated, install dowel rods on 18-inch centers around the full perimeter of concrete base. 4. Install epoxy-coated anchor bolts that extend through concrete base and anchor into structural concrete floor. 5. Place and secure anchorage devices. Use setting drawings, templates, diagrams, instructions, and directions furnished with items to be embedded. 6. Install anchor bolts to elevations required for proper attachment to supported equipment

13 B. Arrange installation of units to provide access space around air-handling units for service and maintenance. C. HVAC Contractor shall employ the services of an Electrician for 120V field wiring for the receptacles and lighting between the Sections of the AHU's. Required field wiring will include the following: 1. Connection of a 120V/1 PH/60 Hz power supply at one of the light switch enclosures for the lighting circuit. 2. Connection of a 120V/1 PH/60 Hz power supply at one of the GFI receptacle (receptacle will be wired in parallel by the manufacturer). 3. Connection of a power supply to the fan motors. See schedule for Voltage requirements. 4. Wiring connections crossing each shipping break. D. Do not operate fan system until filters (temporary or permanent) are in place. Replace temporary filters used during construction and testing, with new, clean filters. E. Install filter-gage, static-pressure taps upstream and downstream of filters. Mount filter gages on outside of filter housing or filter plenum in accessible position. Provide filter gages on filter banks, installed with separate static-pressure taps upstream and downstream of filters. F. Comply with requirements for piping specified in other Division 23 Sections. Drawings indicate general arrangement of piping, fittings, and specialties. G. Install piping adjacent to air-handling unit to allow service and maintenance. H. Connect piping to air-handling units mounted on vibration isolators with flexible connectors. I. Connect condensate drain pans using NPS 1-1/4, ASTM B 88, Type M copper tubing. Extend to nearest equipment or floor drain. Construct deep trap at connection to drain pan and install cleanouts at changes in direction. J. Hot- and Chilled-Water Piping: Comply with applicable requirements in Division 23 Section "Hydronic Piping." Install shutoff valve and union or flange at each coil supply connection. Install balancing valve and union or flange at each coil return connection. K. Connect duct to air-handling units with flexible connections. Comply with requirements in Division 23 Section "Air Duct Accessories." 3.2 MANUFACTURER STARTUP A. Start-up shall be performed by the manufacturers' factory-employed service personnel; a local representative or distributor is not acceptable. A training session shall be provided by the manufacturer's representative at the time of startup and shall fully video recorded by the manufacturer's representative so that such sessions can be later reviewed by the Owner's staff on an as-needed retraining basis. All such videos are to become the property of the Owner at the end of each applicable training period. Manufacturer's representative shall verify media format with the Owner prior to recording training sessions END OF SECTION