PART 1 - GENERAL 1.1 RELATED DOCUMENTS A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Specification Sections, apply to this Section. B. Related Sections: The following Sections contain requirements that relate to this Section: 1. Section 15074 "Vibration and Seismic Controls for HVAC Piping and Equipment" for inertia bases, isolation bases, and vibration isolation hangers and supports. 2. Section 15083 "HVAC Insulation" for field-applied equipment insulation. 3. Section 15861 "Air Filters" for filters and housings not an integral part of centralstation air-handling units specified in this Section. 4. Division 16 Section "Disconnect Switches and Circuit Breakers" for field-installed disconnect switches. 5. Division 16 Section "Motor Controllers" for field-mounted alternating-current starters. 6. Division 16 Section "Motor-Control Centers" for motor-control centers used for centralizing or grouping controls in building projects. 1.2 SUMMARY A. This Section includes constant-volume, central-station air-handling units with coils for indoor installations. 1.3 SCOPE OF WORK A. GENERAL 1. Furnish each air handling unit complete with mixing box section, blender section, prefilter section, preheat coil section, fan section, diffuser section, cooling coil section, final filter section, and discharge section, along with fans, filters, coils, motors, blenders, dampers, louvers, hoods, roof curbs, vibration isolation equipment and all accessories as herein described, and all associated hardware required for a complete installation. 2. Furnish a complete set of submittals as described herein. 3. Provide engineering and installation services as described herein. 4. Provide spare motors. 5. Provide equipment weights, the fan WR 2, fan operation speeds and fan sound power levels to the Contractor for proper selection of auxiliary equipment. 6. Provide complete start-up services as herein described. 7. Provide instructions to Owner as herein described. 8. Provide Owner's Manual, complete operating instructions and spare parts lists as herein described. 9. Provide a minimum one (1) year parts and labor service warranty. B. The work by the Contractor shall generally include the following: Page 1 of 28
1. Provide the Automatic Temperature Control Manufacturer with a complete set of approved shop drawings for each fan volume control device to be connected into the automatic temperature control system. 2. Provide the Building Direct Digital Control System Manufacturer with a complete set of approved shop drawings for each fan and each volume control device to be connected into the building direct digital control system. 3. Provide the Noise and Vibration Control Manufacturer with a complete set of approved shop drawings for each unit which will be installed with these devices. 4. Provide the Variable Frequency Drive Manufacturer with a complete set of approved shop drawings for each fan which will be driven by these devices. 5. Provide the Air Balancing Subcontractor with a complete set of approved shop drawings for each unit to be installed on this project. 6. Receive and unload the air handling units upon delivery to the job site. 7. Inspect each unit section as it arrives on the job site. Notify the CSU Manufacturer and Architect of any shipping damage immediately. 8. Clear area where unit is to be set of any construction materials or debris. 9. Construct level equipment pads in accordance with Division 3 and Division 15, "Vibration Control" Section. 10. Provide structural steel frame to support the unit a minimum of 24 inches above the floor. Refer to Section 15050 "Basic Mechanical Materials and Methods" for further requirements. 11. Hoist and set units in their proper position. Use spreader bars to hoist the unit sections to avoid damaging casings. 12. If units ship in more than one section, provide all labor and equipment. Follow the manufacturer's instructions for placing and field joining sections. 13. Provide all final chilled water, hot water, and drain piping connections. 14. Provide humidifiers (where applicable). 15. Provide automatic temperature control connections and control dampers. 16. Release the fan spring isolator shipping restraints. 17. Thoroughly clean the interior and exterior of the units. Remove all foreign objects and clean all interior and exterior surfaces with a mild detergent (soap and water). Do not use any abrasives or solvents without first consulting the CSU Manufacturer. 18. Install filter media in filter frames. (Running units without filter media is strictly prohibited). 19. Coordinate all work associated with the air handling unit installation. 20. Provide unit start-up services as described herein. 21. Notify CSU Manufacturer that installation is fully completed and that unit is ready for start-up. 22. Assist the CSU Manufacturer during start-up by providing tools, test equipment, and mechanics to accomplish the start-up. 23. Submit to Architect for approval, three (3) copies of installation, operation and maintenance manuals as described herein. C. The work by the Electrical Contractor will generally include providing power wiring between the 460 volt (208 volt), 3 phase power source and the unit power disconnect and between the disconnect switch and the motor. D. The work by the General Contractor generally includes the following: 1. Provide structural grillage as indicated on the drawings to support the unit. 2. Cut openings in roof and roof membrane to template established during shop drawing submission. 3. Install roof curbs furnished by the Contractor. 4. Seal and flash roof curbs and unit to the (existing) roofing system (membrane). Page 2 of 28
1.4 SUBMITTALS A. General: Submit each item in this Article according to the Conditions of the Contract and Specification Sections. B. No equipment shall be fabricated or delivered until receipt of approved shop drawings from the Architect. C. Provide the following information with each shop drawing/product data submission: 1. Complete specification of the equipment which will be provided including all optional equipment. All equipment shall be tagged. Refer to Section 15075 "Mechanical Identification" Section for further requirements. 2. Dimensioned arrangement drawings for each air handling unit including a plan, elevation, and end view of the assembled unit with overall dimensions, support locations, and weights. Drawings shall also indicate all electrical, piping, and ductwork connection locations and sizes. 3. Assembly and erection drawings. 4. Fan data as specified hereafter. 5. Each component of the unit shall be identified and shall include capacity and performance data corrected to actual operating conditions, temperatures, and altitudes, physical dimensions, and material of construction, including where applicable, gauges of metal. For coils, furnish performance data in computer output format, disclosing all coil selection conditions. 6. Schematic power wiring diagrams including power requirements and interface with controls where applicable. Differentiate between manufacturer-installed wiring and field installed wiring. 7. Support details, including equipment loads at all bearing points. 8. Structural load requirements and unit weight for coordination with the structural steel support. 9. List of spare parts for one year's normal maintenance; include all "off the shelf" readily available purchased items on this list. List shall include subassembly part number (identifiable in maintenance manual or on shop drawings), manufacturer's name, manufacturer's part number, and a part description. Include drive-belt part numbers. 10. Installation, operation, emergency and preventative maintenance, and lubrication instructions in shop manual format. D. Provide the following submittal information for the fans: 1. Submittal data shall show that all fans bear the AMCA Certified Performance Seal for both air and sound performance at the capacities specified on the Drawings. 2. Arrangement drawings showing proposed scroll arrangement, rotation, discharge, and drive arrangement, motor location, motor power connection location, access door locations and drain connection locations as required. 3. Arrangement drawings including WR 2 for the fan wheel and drive assemblies, include individual WR 2 for each drive component. 4. Capacity and performance data corrected to actual operating temperature and altitude. Fan curves shall have operating points indicated. Refer to Engineering Service article in this section for actual fan curves and data required. 5. Motor data to verify motor type, efficiency and starting characteristics. 6. Fan noise characteristics including sound power levels for the 8 octave bands and a single sound power A-scale weighted level or sound levels in "Sones" Page 3 of 28
1.5 QUALITY CONTROL when the fan is operating at its peak horsepower output. Refer to Engineering Service article in this Section for further data. 7. Damper motor data for fan dampers and fan inlet vanes. A. NFPA Compliance: Central-station air-handling units and components shall be designed, fabricated, and installed in compliance with NFPA 90A, "Installation of Air Conditioning and Ventilating Systems." B. UL Compliance: Electric coils, along with complete central-station air-handling unit, shall be listed and labeled by UL. C. ARI Certification: Central-station air-handling units and their components shall be factory tested according to the applicable portions of ARI 430, "Central-Station Air-Handling Units," and shall be listed and bear the label of the Air-Conditioning and Refrigeration Institute (ARI). D. UL and NEMA Compliance: Provide motors required as part of air-handling units that are listed and labeled by UL and comply with applicable NEMA standards. E. All fans shall be rated in accordance with AMCA Standard 210 and shall comply with the AMCA Certified Ratings Program. F. All fans shall bear the AMCA Seal. G. All coils shall be certified in accordance with ARI Standard 410. H. All gas heating sections shall be AGA approved and shall have IRI approved gas trains. I. Comply with NFPA 70 for components and installation. J. Listing and Labeling: Provide electrically operated components specified in this Section that are listed and labeled. 1. The Terms "Listed" and "Labeled": As defined in the National Electrical Code, Article 100. 2. Listing and Labeling Agency Qualifications: A "Nationally Recognized Testing Laboratory" (NRTL) as defined in OSHA Regulation 1910.7. K. Coordination: Coordinate layout and installation of central-station air-handling units with piping and ductwork and with other installations. 1.6 WARRANTY A. The CSU Manufacturer shall warrant all equipment for one (1) year as described herein and as further required in the "Warranty" article of this Specification. B. The CSU Manufacturer shall include in his warranty the cost of all parts, including freight or airfreight as required to remedy any breakdown situation relating to the installation. C. Correct all critical defects within 24 hours following the Owner's verbal notification of a problem, for a period of one (1) year after acceptance by the Owner. A critical defect is defined as a defect in fan operation through bearing or shaft failure resulting from bearing Page 4 of 28
burnout, or as a failure in fan operation resulting in belts breaking frequently or as a coil failure (leak). D. Correct all non-critical defects, such as casing leaks, fan noise problems, vibration problems, excessive bearing noise or belt set replacement, within 30 days following the Owner's written notice, for a period of one (1) year after acceptance by the Owner. E. Acceptance date shall be considered date of issuance of a certificate of substantial completion. F. Failure to correct any defective work or equipment within 24 hours or within 30 days, as applicable, will render conduct negligent, in which case the Owner will be entitled to proceed with the correction of such defects at his discretion and to charge the Contrator cost plus 10% of the expenses incurred. G. The Contractor shall be responsible to repair all damage caused by any defect in the work or equipment, whose repair is covered under warranty. H. The CSU Manufacturer shall coordinate all labor and material provisions of the warranty with the Contractor. 1.7 DELIVERY, STORAGE, AND HANDLING A. The CSU Manufacturer shall tag or mark parts of work to be field-assembled durably and legibly with indelible markings, giving Contractor's order number to enable the Contractor to identify the various parts and erect work without delay. B. The CSU Manufacturer shall tag and place separate parts too small to mark in containers plainly marked on the outside as to their contents and the Contractor's purchase order number. In shipping bolts, different kinds and sizes shall be kept separate, either by separate containers or partitions in the same container. C. Before shipment, the CSU Manufacturer shall coat or cover finished surfaces of machinery and equipment thoroughly with a protective material that prevents rust, but can be readily removed when erected. D. The CSU Manufacturer shall protect equipment against damage during shipment and delivery. E. The CSU Manufacturer shall cap or plug pipe ends and tapped holes for pipe connections before shipment. F. After loading equipment for shipment, the CSU Manufacturer shall wire the Contractor the name of the carrier, car number, description of equipment, order number, weight of heaviest piece, shipping point, date of shipment, and estimated time of arrival. G. Lift and support units with manufacturer's designated lifting or supporting points. 1.8 SEQUENCING AND SCHEDULING A. Coordinate size and location of concrete housekeeping bases. Cast anchor-bolt inserts into base. Page 5 of 28
B. Coordinate size and location of structural-steel support members. 1.9 EXTRA MATERIALS A. Furnish extra materials described below that match products installed, are packaged with protective covering for storage, and are identified with labels describing contents. B. Filters: Furnish 1 set for each central-station air-handling unit. C. Fan Belts: Furnish 1 set for each central-station air-handling unit fan. D. Gaskets: Furnish 1 for each sectional joint of each central-station air-handling unit. PART 2 - PRODUCTS 2.1 MANUFACTURERS A. Available Manufacturers: Subject to compliance with requirements, manufacturers offering products that may be incorporated into the Work include, but are not limited to, the following: B. Manufacturers: Subject to compliance with requirements, provide products by one of the following: 1. York International Corporation. 2. Temtrol Inc. 3. Carrier Corp.; Carrier Air Conditioning Div. 4. The Trane Company. 2.2 FACTORY BUILT CENTRAL STATION AIR HANDLING UNITS - GENERAL A. All factory built central station air handling units for this project shall be the product of one CSU Manufacturer. Approved CSU Manufacturers are listed elsewhere in this Section of the Specification. B. Where required, portions of central station air handling units must be items manufactured by companies other than the CSU Manufacturer. These items would include filter housings, integral face and bypass coils, sprayed coil units, and air blender boxes. These items shall be provided by the Contractor. 1. Interconnecting ductwork shall be constructed in accordance with "Metal Ducts" Section. 2. Interconnecting ductwork shall be insulated in accordance with "Mechanical Insulation" Section. 3. Interconnecting ductwork shall be isolated for vibration purposes in accordance with "Vibration Controls" Section. C. The Contractor shall be responsible for reviewing the appropriate architectural and structural drawings, for visiting the site prior to bidding and, after award of contract and for coordinating installation of the air handling unit(s) in the location shown on the drawing without extra cost to the Owner. D. It should be expressly understood that these units should fit through all available openings, doorways and corridors, and into existing elevators within the contract price. Page 6 of 28
2.3 INDOOR FACTORY BUILT - CENTRAL STATION AIR HANDLING UNIT - CONSTRUCTION A. All sectionalized cabinet modules and accessories shall be constructed of mill galvanized sheet, formed and reinforced to provide a rigid assembly. Formed panels shall be removable to provide easy access to internal components. Each of the sectionalized modules and accessories shall be factory assembled. B. All fan and coil sections shall be insulated with (1" - 3/4 PCF,) 1" - 1-1/2 PCF (1-1/2" - 1 PCF) glass fiber insulation with a black flame-resistant coating. The insulation shall be affixed to the casing with waterproof adhesive and permanent fasteners. Alternate insulation systems regularly provided as standard or as a standard option by the various CSU Manufacturers which perform similarly are acceptable. The insulation and adhesive shall meet the flame and smoke generation requirements of NFPA-90A. C. Drain pans shall be constructed of heavy gauge welded galvanized steel and drain connections shall be provided on both sides of the pan. Drain pans shall have an inner pan (double drain pan) with 1" - 3/4 PCF insulation sandwiched between pans. The drain pans shall extend completely under the fan and coil section of draw-through units and under the coil sections of blow-through, multizone, or vertical units. D. Coil sections having stacked coils shall have additional intermediate drain pan(s), each with two drop tubes to guide condensate to the main drain pan without flooding of the lower coil(s). Coil sections must have tracks extended the full width of the unit and depth of coils to provide easy removal for service and maintenance. The coil section must have an available coil space of 10", 20", 28" or 36" as shown on the drawings. Spacers, 6-inch minimum, for control sensor installation shall be provided between coils. E. Provide where shown on drawings draw-through, sprayed coil section which shall have heavy gauge, mill galvanized steel casing with latch-type access door in the spray section, stainless steel spray tree assembly complete with square pattern spray nozzles, 14" cooling coil space with stainless steel troughs and downspouts, and 3-bend stainless steel eliminator plates on 1-1/8" centers; all assembled over heavy gauge, welded steel tank, with interior and exterior surfaces commercially sandblasted and painted with one coat of zinc chromate, iron oxide, or phenolic paint. Furnish copper suction screen, drain connection, adjustable overflow connection and suction connection in the tank. Also furnish make-up water connection with brass float valve in the tank, and a quick-fill connection on the casing panel. Furnish separate, floor-mounted, close-coupled pump to be mounted and piped by the Contractor. Exterior of sprayed coil section shall be insulated after installation by the Contractor under the "Mechanical Insulation" Section. The tank shall be mounted on a 2" insulation board furnished and installed by the Contractor. Coils shall slide into unit through a removable side panel. 1. Refer to Division 15 Piping Sections for piping and pipe specialty requirements. 2. Refer to "HVAC Pumps" Section for pump and pump specialty requirements. 3. Refer to "Mechanical Insulation" Section for casing insulation requirements. F. Face and bypass coil sections shall be of the external or internal type required by the schedule and as indicated on the drawings. The dampers shall be multi-leaf, opposed acting blades interlocked with one control point. The blades shall rotate in nylon bearings providing smooth action and requiring no lubrication. Dampers shall be sectionalized to limit blade length, to prevent warpage and to assure a tight closure. 1. The face and bypass dampers shall be controlled by a single damper motor or by multiple damper motors mechanically interlocked in parallel. Page 7 of 28
G. Mixing box sections shall be provided (without dampers) with multi-leaf, parallel acting mixing dampers, with inter-connected return air and outdoor air dampers. Blades shall rotate in nylon bearings providing smooth action and requiring no lubrication. The dampers shall be sectionalized to limit blade length, to prevent warpage, and to assure a tight closure. 1. The mixing dampers shall be controlled by a single damper motor or by multiple damper motors mechanically interlocked in parallel. H. Combination filter mixing boxes shall combine the filtering and mixing functions in one standard section, and shall be provided with slots for nominal 2" thick standard size filters available as "throw-away", permanent "cleanable" or "replaceable media" type with access from either side with hinged access doors. The unit shall be provided (without dampers) with multi-leaf, parallel acting, mixing dampers, with interconnected return air and outdoor air dampers. Blades shall rotate in nylon bearings providing smooth action and requiring no lubrication. The dampers shall be sectionalized to limit blade length, to prevent warpage, and to assure a tight closure. 1. The mixing damper shall be controlled by a single damper motor or by multiple damper motors mechanically interlocked in parallel. I. Flat filter (Angle filter) sections shall be provided with slots for nominal 2" thick standard sized filters available as "throw-away", permanent "cleanable" or "replaceable media" type accessible from either side with hinged access doors. All filter sections shall be of the flat or angle type as necessary with filter face velocities not exceeding the filter manufacturer's recommended maximum face velocities or those scheduled on the drawings. J. Bag filter sections shall be constructed of mill galvanized panels and frame. The filter section shall have full-size gasketed access doors on both sides and shall be equipped with a 2" thick prefilter rack. The filter racks shall be provided full length with nylon sliding seals. The bag filter section shall be suitable for standard bag or cartridge filter media scheduled on the drawings. The high efficiency bag filter section shall have a housing depth of 38" and scrim support blanket on leaving side of the media. The medium efficiency bag filter section shall be equipped with replaceable cartridges and 24" deep housings. K. Roll filter sections shall be constructed of mill galvanized panels and frame. The filter section shall have full size gasketed access doors on both sides with either right-hand or left-hand media loading as required. The section shall be equipped with a 115/230 volt, 60 cycle, single phase motor with internal overload protection, media run-out switch and signal light, disconnect switch, manual switch, factory assembled, U.L. approved and internally wired. The filter media feed shall be controlled by (NOTE TO SPECIFIER - PICK ONE) an adjustable timer, a pressure switch, or an adjustable timer/pressure switch combination. The section shall have a fan interlock relay, additional remote run-out light, 460-Volt transformer and 1/6 HP gear motor. Filter media roll system shall be suitable for 65-ft. rolls of 3/4" thick bonded virgin Dacron with heavy scrim backing. L. Diffuser sections shall be constructed of heavy gauge, reinforced, mill galvanized panels for maximum rigidity, and shall include a factory installed, perforated diffuser plate designed to provide even distribution of high velocity fan discharge air across the coil face assuring required heat transfer. All edges of plate shall be healed or shall be trimmed out so that no sharp edges are exposed. Page 8 of 28
M. Multizone section cabinets shall be constructed of mill galvanized steel panels. All damper sections shall have external connections readily accessible. Multizone dampers shall be fully gasketed and shall be provided with zinc plated shafts, linkage and hardware. Extended splitters shall be provided between each damper section for ease of "S" slip duct connections. Hot, (intermediate,) and cold air dampers shall be opposite acting (secured at (60 deg.) 90 deg. to each other) and shall rotate in nylon bushings. The entire perimeter of each damper blade shall close against solid stops which are gasketed with 2 PCF density polyurethane foam. N. Damper motors shall be provided by the CSU (Automatic Temperature Control, Building Direct Digital Control System) Manufacturer and shall be pneumatic type suitable for 3-15 psig modulating air signal and 20-25 psig main air and shall be similar to those specified in Section 15900 HVAC Instrumentation and Controls. Dampers shall fail to the positions discussed in those sections on loss of a modulating air signal or loss of the main air signal. 1. Damper motors for face and bypass coil application and for mixed air application shall be provided with pilot positioners. 2. Damper motors for multizone units shall be provided (with) without pilot positioners. 2.4 ROOF MOUNTED CENTRAL STATION AIR HANDLING UNIT - CONSTRUCTION A. Units shall have a base assembly manufactured of structural steel members, electrically welded to form a rigid equipment mounting structure. All major components shall be supported from the base. Independent sectionally constructed units are unacceptable. B. The unit construction shall include an electrically welded upper frame, fabricated of structural steel tubing or equivalent. This upper frame shall be welded to the unit base to form a rigid, unitized assembly. The entire structural steel assembly shall be painted with a rust inhibiting enamel. C. The unit base shall overhang the roof curb for water run-off and shall have a fabricated recess with a continuous surface to seat on the roof curb gasket, providing a positive, weathertight seal. D. Integral lifting lugs shall be provided. Lifting lugs shall be suitable for use as unit tie down points. E. Units shipped in sections shall be designed for field assembly. Unit sections shall be flanged at the entire perimeter to provide a gasket surface. Matching holes shall be drilled in the flanges with nuts, screws, gasket, and washers provided. F. Exterior panels shall be constructed of a minimum of 20 gauge galvanized steel formed panels. (Options: 18 and 16 gauge galvanized steel; 18 and 16 gauge aluminum). G. All panels shall be fastened to the unit frame with 1-inch square clips and self-tapping screws. Pop riveted or spot welded fastenings are not acceptable. All exterior panel joints shall be recessed, mastic coated, and covered with a removable panel cap. All exterior panel-to-panel joints shall be caulked for water and air tightness. H. Exterior casing screws shall be zinc chromate plated or stainless steel and shall have cup washers with neoprene grommets to prevent damage to the paint finish and to form a weathertight seal. Page 9 of 28
I. The unit roof shall have a minimum pitch of 1/2 inch per foot. Rain drip lips shall be provided above the access doors. The exterior panels and doors shall form essentially smooth, continuous surfaces for a pleasing appearance. J. The unit interior shall have step in/walk in platforms on the floor of the unit inside all access doors to protect the insulation. (Options: 24, 20, 18 and 16 gauge solid galvanized steel; 20, 18 and 16 gauge perforated steel; 20, 18 and 16 gauge solid aluminum; 20, 18 and 16 gauge perforated aluminum interior walls). K. All air inlet and discharge openings in accessible portions of the base of the unit shall be covered with removable grating capable of supporting a man. L. All exterior panels, the top, and the base shall be insulated with a minimum of 2 inch thick, 3 PCF fiberglass insulation glued in place. Smoke and flame spread ratings shall be in accordance with NFPA 90A. Alternate insulation systems regularly provided as standard or as a standard option by the various CSU Manufacturers which perform similarly are acceptable. Polyurethane and polystyrene insulations are not acceptable. M. All mixing box sections shall be designed to promote good mixing of outdoor air and return air streams. Outside and exhaust air openings shall not be on the same side of the unit in order to minimize recirculation. 1. Return air damper assemblies shall be low leakage type dampers. Damper blades shall be fabricated from a minimum of 16-gauge galvanized steel. Maximum blade length shall not exceed 48 inches. Blade ends shall be sealed with spring steel seal and blade edge seals shall be gasketed. Damper shafts shall be fabricated from solid steel and mounted in the frame with bronze or nylon bearings. Damper velocities shall be matched with the outdoor air and relief air dampers and shall not exceed 2000 FPM. 2. Outdoor air (and relief air dampers) shall be ultra-low leak dampers with extruded aluminum blades. Maximum blade length shall not exceed 48 inches. Blade ends shall be sealed with spring steel and blade edge seals shall be extruded vinyl. The damper shafts shall be fabricated from 1/2 inch plated steel hex and mounted in frame with molded synthetic bushings. Damper air leakage shall not exceed 6 CFM per square foot at 4-inch w.g. static pressure. Damper velocities shall not exceed 2000 FPM on the outdoor air and relief air dampers. 3. Outdoor and relief air openings shall be covered with rain hoods or storm proof louvers as indicated on the drawings. Rain hood velocities shall not exceed 1000 FPM. Louver velocities shall not exceed 500 FPM on the outdoor air intake and 1000 FPM on the relief air discharge. All louvers and hoods shall be fitted with bird screen. N. Damper motors shall be provided by the CSU (Automatic Temperature Control, Building Direct Digital Control System) Manufacturer and shall be pneumatic type suitable for 3-15 psig modulating air signal and 20-25 psig main air and shall be similar to those specified in Section 15900 HVAC Instrumentation and Controls. Dampers shall fail to the positions discussed in those sections on loss of modulating air signal or loss of the main air signal. Damper motors shall be suitable for the low ambient outdoor temperatures experienced at the job site. 1. Damper motors for face and bypass coil application and for mixed air application shall be provided with pilot positioners. O. The filter section shall be supplied complete with galvanized steel filter racks as an integral part of the unit. Filters shall be accessible from both sides of the unit. The filter section shall be suitable for 2" thick panel prefilter and high efficiency bag or cartridge Page 10 of 28
filters as specified. Bag or cartridge filters shall slide into galvanized steel racks contained within the unit which shall include 2-inch thick slots for prefilters. P. Return air section shall include a plenum, return fans, relief air discharge dampers and outdoor air and return air dampers. Q. The mixed air section shall be designed to form a plenum. Outdoor air arrangement shall be (0 to 30% outdoor air with manual control) (0 to 100% outdoor air with manual control) (0 to 100% outdoor air with remote 0 to 100% outdoor air with economizer control). 1. 0 to 30% manual outdoor air control shall consist of a manual quadrant damper mounted in the outdoor air intake hood. 2. Outdoor air on all 0 to 100% outdoor air sections shall be introduced from both sides of the unit through horizontal louvered intake hoods. The unit floor of the outdoor air section shall be sloped for water drainage. The outdoor air and return air dampers shall be sized to handle 100% of the supply air volume and arranged vertically to converge the return and outdoor air streams in a circular mixing pattern. 3. A gravity relief type exhaust air damper shall be provided on all 0 to 100% outdoor air sections and shall be located in the return air section to relieve excess return air out the back of the unit. Relief dampers shall be lined with urethane gasketing on the contact edges. 4. The 0 to 100% manual outdoor air sections shall consist of outdoor air, return air, and relief air dampers. Control of the outdoor and return air dampers shall be from a single, manually controlled lever accessible from the filter section. 5. A 0 to 100% remote rheostat control shall consist of outdoor air, return air, relief air dampers, damper motor and remote wall mounted rheostat. The rheostat shall be complete with indicator faceplate and knob to provide motorized control of the dampers. The faceplate and knob shall be supplied for field mounting (remote monitoring panel shall include the rheostat). The damper motor shall be of the modulating spring return type. 6. A 0 to 100% outdoor air economizer control shall consist of outdoor, return air and relief air dampers, adjustable potentiometer, damper motor, and an adjustable enthalpy control mounted in the outdoor air stream. The adjustable potentiometer shall control the minimum outdoor air damper position for fresh air requirements. Potentiometer shall be mounted on the unit (for units without remote monitoring panel). An enthalpy control shall be provided to sense the dry bulb temperature (and relative humidity) of the outdoor air for use in cooling. The damper motor shall be of the modulating spring return type. R. In the cooling coil section, a mastic coated primary drain pan shall be provided with the cooling coil. The pan shall extend beyond the leaving side of the coil and underneath the cooling coil connections. The drain pan shall be connected to a threaded drain connection extended through the unit base. Units shall be provided with a secondary mastic coated drain pan connected to the primary drain pan. S. Cooling coil sections having stacked coils shall have additional intermediate drain pan(s), each with two drop tubes to guide condensate to the main drain pan without flooding the lower coil(s). T. Man-size hinged access doors shall be provided and arranged to permit ready access to all internal components. Doors shall have a minimum of (three) 3 galvanized hinges and (two) 2 high compression latches with handles. Doors shall be insulated double wall type constructed with corners welded and ground smooth. Door gasketing shall be closed cell polyvinyl chloride foam type. (Options: 302 stainless steel hinges; galvanized or Page 11 of 28
2.5 FANS stainless steel full height hinges; bulb type door gasket; inside/outside door latches; key lock door latches; and door tie backs). U. All piping connections made on the exterior of the unit shall be provided with weathertight removable insulated sheet metal pipe enclosures. All humidifier steam separators (pots) shall be provided with removable weathertight insulated sheet metal pipe enclosures. All pipe enclosures shall be constructed similarly to the remainder of the unit. V. The entire exterior and interior of the unit shall be completely cleaned and finished with an air dried (beige) enamel which meets or exceeds Federal Specifications TTP636 exposure requirements. (Options: exterior air dried chemical resistant epoxy over primer, interior enamel; exterior and interior epoxy over primer; and exterior special color enamel, interior beige enamel). The color shall be selected by the Architect. A. Provide fans of the size and type listed on the fan schedule for each unit. Fans shall be an integral part of the fan section of the unit. Fans shall be double width, double inlet type with centrifugal wheels. B. Low and medium pressure fans with forward curved blades shall have the wheel and scroll constructed of mill galvanized steel. The low-pressure fans shall be used for static pressure duties up to 3" w.g. and medium pressure fans shall be used for static pressure duties 3" to 6" w.g. C. Medium and high pressure fans with backward inclined air foil blades shall have wheels and streamlined inlet cones constructed of heavy gauge aluminum, for low starting inertia, and spark free operation, with scrolls constructed of mill galvanized steel. D. Fan scrolls and internal bearings shall be rigidly mounted and securely fastened to the unit base. External bearings where required on indoor units shall be fastened to a rigid heavy-gauge channel securely mounted to the unit. E. Fan bearings shall be self-aligning, pillow block, or flange type with regreaseable ball bearings and shall be selected for an average L-10 life of at least 200,000 hours for low and medium pressure units and 130,000 hours for high pressure units. Bearings shall be factory lubricated and shall be equipped with standard hydraulic grease fittings. Extended lube lines, as necessary, shall terminate at one location on the outside of the unit preferably on the drive end and shall include extensions to allow greasing without removal of the belt guard. F. Fan shafts shall be selected to operate well below the first critical speed and each shaft shall be factory coated after assembly with an anti-corrosion coating. Units with over five square feet of face area shall have hollow shafts. G. Fan wheels and shafts shall be designed for continuous operation at maximum rated speed and motor horsepower. Fans and shafts shall be statically and dynamically balanced as an assembly. The entire unit shall undergo a final two-plane balance after assembly. H. Fans shall be AMCA Certified for both air and sound performance at the capacities listed on the drawings. Page 12 of 28
2.6 FAN DRIVES A. For belt-driven fans serving critical applications, the CSU Manufacturer shall provide V-belt drives with a minimum service factor of 2.0 with all belts in service and of 1.3 with one belt broken. Drive horsepower ratings shall be based on the nominal fan motor horsepower. This requirement applies to all conditioning units and fans. B. For all other applications the CSU Manufacturer shall provide V-belt drives with a service factor of 1.65 minimum based on nominal fan motor horsepower. C. V-belt drives for motor sizes up to 25 horsepower shall be adjustable type (plus or minus 10 percent) with the fan sheave being fixed and the motor sheave being adjustable; the drive shall be selected with the fan operating near the mid-point of the drive sheave based on the performance scheduled under the present condition. D. V-belt drives for motor sizes 30 horsepower and larger shall be fixed sheave type for both the fan and the motor and shall be selected based on the performance scheduled under the present condition. E. All exposed V-belt drives shall be enclosed in and OSHA approved removable belt cover with tachometer openings. F. The CSU Manufacturer shall provide all V-belts in matched sets for all initial installations and for warranty work. G. Under the base contract and after initial balancing, the CSU Manufacturer shall furnish the Air Balancing Subcontractor with the correct fixed pitch sheave(s) (with belts) to match the air balance requirements. These sheaves shall be installed by the Contractor at no additional charge to the Owner. 2.7 FAN MOTORS A. Refer to "Motors" and Motors and Variable Frequency Drives Sections of Division 15. B. The Contractor shall provide spare motors for the fans provided under this Contract. 1. The spare motors required shall include one motor of each size, type, speed, enclosure, voltage, and configuration and which is 7-1/2 horsepower or larger. 2.8 COOLING COILS A. Refer to Section 15790 "Air Coils" Section for cooling coil specifications. Cooling coils shall be arranged in the unit for horizontal airflow. 2.9 PREHEATING COILS A. Refer to Section 15790 "Air Coils" Section for hot water preheating coil specifications. 2.10 ELECTRIC HEATING COILS A. The electric heating element shall be open resistance type designed for direct exposure to the air stream. Page 13 of 28
B. Electric heat sections shall be open coil heater sections with integral control panel and aluminized steel casing. They shall have 80% nickel and 20% chromium coil elements machine crimped to stainless steel terminals and amply supported on ceramic bushing isolators. C. Electric heaters shall be connected in delta arrangement and provided with contactors, dual element fuses and backup contactor(s) to meet the requirements of the National Electric Code. D. The heating coil shall be complete with a NEMA 12 control panel which contains the following: 1. Control transformer with two (2) fused primary legs, and one fused and one grounded secondary leg. 2. Disconnect switch. 3. Magnetic contactor for each stage of heating. 4. Three (3) phase circuit breaker (fuse) protection for each stage of heating. (Provide 3 spare fuses of each size provided on the project). 5. Line side terminal blocks. 6. Pressure electric switches or pneumatic step controller to bring stages on and off line. Coordinate with Section 15900 HVAC Instrumentation and Controls. 7. Control sequence terminal strip for external controls provided by the BDDC Manufacturer. Coordinate with Section 15900 also. 8. Each heater shall be equipped with an automatic reset high temperature limit controls set at 130 deg. F and a manual reset high temperature limit control set at 180 deg. F. 9. The unit shall be interlocked with the supply fan auxiliary contact to energize the heater only when the fan is running. 10. The unit shall be furnished with a pressure differential switch to de-energize the electric heating in the event of reduced or zero airflow. E. Power wiring from the contactors to the heating elements shall be nickel plated copper wire with high temperature insulation, rated at 600 volts. F. Electrical coils shall be installed in the preheat, reheat or hot deck positions as shown on the drawing with sizes, capacities and number of stages as scheduled. G. All electric heating coils shall be U.L. listed and shall bear the U.L. listed as an assembly. H. Air flow distribution baffles shall be provided to assure uniform airflow and restrict entry of foreign materials. I. Design Basis: Brasch Manufacturing. 2.11 AIR FILTERS A. Refer to Section 15861 "Air Filters" for air filter specifications. B. Air filter media shall be shipped loose to the job site for field installation by the Contractor. 2.12 AIR FILTERS AND HOUSINGS A. Refer to Section 15861 "Air Filters" for air filter and air filter housing specifications. Page 14 of 28
B. Air filter media shall be shipped loose to the job site for field installation by the Contractor. 2.13 ADAPTOR SECTIONS A. Where required and where shown on the drawings the Contractor shall provide adaptor sections between various sections of factory built central station air handling equipment, sprayed coil units, and filter housings. B. Adaptor sections shall be provided under Section 15815 "Metal Ducts" and insulated under Section 15083 "HVAC Insulation". 2.14 AIR BLENDERS A. Refer to Section 15820 "Duct Accessories" for air blender specifications. 2.15 AIR BLENDER MIXING BOXES A. Provide air blender mixing boxes of the type, size, pressure drop and capacity as scheduled and shown on the Drawings. Units shall consist of dampers, blenders and mixing section fitted together into a rigid unit. All units shall be factory-built and tested, and shall be installed in strict accordance with manufacturer's recommendations and as shown on the Drawings. Units shall be designed to connect directly to the main central station unit. B. Units shall be constructed of galvanized steel and reinforced for rigidity with all welded construction. Damper section shall be built around 12 and 14 gauge framework. Units shall have 1 inch thickness 2 PCF density insulation throughout interior of housing. The insulation and adhesive shall meet the flame and smoke generation requirements of NFPA 90A. C. Air inlets shall be configured in such a way that return air and outside air may enter in any of four arrangements. Arrangement shall be field adjustable by removing and re-installing inlet panels. D. Units shall be capable of providing mixed air temperature within plus or minus 6 F standard deviation from the theoretical mixed air temperature. E. Air blenders shall be completely fixed devices with no moving parts. F. Units shall be provided without dampers. G. Dampers shall be parallel blade low-leakage proportioning type with leakage rates less than 10 CFM per square foot at 3 inches w.g. static pressure. Dampers shall have blades of 16-gauge steel with neoprene seals on blade edges and on top, sides and bottom of frame. Damper blades shall be no wider than 6 inches. Damper blades shall be locked to steel rods rotating on rustproof bushings. Dampers wider than 48" total width shall be provided with a jackshaft system. H. Damper motors shall be provided by the Automatic Temperature Control (Building Direct Digital Control System) Manufacturer and shall be pneumatic type suitable for 3-15 psig modulating air signal and 20-25 psig main air and shall be similar to those specified in Page 15 of 28
Section 15900 HVAC Instrumentation and Controls. Dampers shall fail to the positions discussed in those sections on loss of a modulating air signal or loss of the main air signal. I. Units shall have side panels for damper access. Units shall be equipped with duct connection flanges. J. Units shall be as manufactured by Blender Products, Inc. or KEES, Inc. 2.16 CONTROL DAMPERS A. Control dampers will be furnished under Section 15900 HVAC Instrumentation and Controls and installed by the Contractor. B. Refer to Section 15900 HVAC Instrumentation and Controls for control damper specifications. 2.17 DISCONNECT SWITCH A. Each roof mounted air handling unit shall be provided with individual disconnect switches for each fan, each electric heating coil, each refrigerant condensing unit and each control panel provided. B. Refer to "Motors" Section for disconnect requirements. 2.18 LOUVERS A. Provide storm proof louvers with bird screens for relief air discharge and where shown on the drawings for outdoor air intake with roof mounted central station air handling units. B. All louvers shall be manufacturer's standard louver and shall be AMCA rated for pressure drop and water penetration and shall be selected to carry less than 0.02 ounce of water per square foot during a 15 minute period when tested in accordance with AMCA Standard 500. C. All louvers shall be selected for maximum velocities of 500 FPM on outdoor air intakes and of 1000 FPM on relief air discharge. 2.19 AIR HOODS A. Provide air hoods for outdoor air intake with roof mounted central station air handling units. B. The leading edge and the sides of the hood shall extend 6" below the bottom edge of the damper section covered. The leading edge of the hood shall be provided with a rain gutter to prevent droplet carry-over into intake dampers. Hood assembly shall be provided with a bird screen. The hood to unit sheet metal joint shall be caulked to prevent water leakage into intake dampers. If hood is shipped as a subassembly, sealant shall be supplied for field reinstallation and caulking by the contractor. Hoods shall be sized for less than 500 fpm inlet velocity. 2.20 VIBRATION ISOLATION Page 16 of 28
A. Refer to Section 15074 "Vibration and Seismic Controls for HVAC Piping and Equipment" Section for vibration isolation requirements. 2.21 STRUCTURAL STEEL STANDS A. All indoor central station air handling units with sprayed coils and with steam coils shall be provided with structural steel stands. B. Stands for sprayed coil units shall be approximately the same height as the sprayed coil tank depth. C. Stands for units with steam coils shall be a minimum of 24 inches tall to allow for proper installation of the steam coil trap rig. D. Stands shall be constructed of structural steel channels, tubes and beams and shall be suitably braced to prevent swaying or vibration. Columns or posts shall be provided under each vibration isolator and within 6 inches of each accessory section mounting foot. E. Refer to Section 15050 "Basic Mechanical Materials and Methods" for further structural steel requirements, and Section 15065 "HVAC Engineered Equipment and Piping Supports" for further requirements concerning engineering design of the steel stands. 2.22 ROOF CURBS AND UNIT FLASHING A. Refer to Section 15074 "Vibration and Seismic Controls for HVAC Piping and Equipment" Section for requirements concerning curb vibration isolation and noise control between the unit and the roof. B. Refer to Division 7 for coordination of roof flashing between the General Contractor and the Contractor. C. Curbs shall be of box section design, 12 gauge galvanized steel with continuous welded corner seams, factory installed wood nailer and insulated with 1-1/2 inch, 3-pound density rigid fiberglass board. Height of raised built-in cant shall be determined in the field. D. The roof curb shall maintain the base of the unit in a level position; the CSU Manufacturer or his representative shall verify the pitch of the roof with the Contractor prior to fabrication. E. The minimum height of the curb shall be such that the roof flashing extends to a point 12 inches above the finished roofline. F. All flashing and counter flashing details shall be submitted for approval. 2.23 AIR COOLED CONDENSING UNIT A. Refer to Section 15672 "Air-Cooled Condensers" for all requirements concerning the air cooled condensing unit. B. The air cooled condensing unit shall be furnished by the CSU Manufacturer complete with all required accessories and specialties. All refrigerant piping and refrigerant piping Page 17 of 28
specialties shall be factory installed with field installation being limited to interconnecting field piping. C. The CSU Manufacturer shall take complete responsibility for the condensing unit, the air handing unit and its accessories as a single functioning unit. 2.24 AIR COOLED CONDENSING SECTION FOR OUTDOOR COOLING UNITS A. The unit shall be provided with an air cooled condensing section as an integral part of the air handling unit. The condensing section shall be complete with refrigerant compressors, air cooled condenser, refrigerant accessories and controls. The condensing unit shall be completely factory piped and wired and shall be delivered from the factory with a complete charge of refrigerant. B. Refrigerant compressors shall be heavy-duty, reciprocating, semi-hermetic type with serviceable oil pump, unloaders and cylinder heads along with reversible, positive displacement oil pump, suction and discharge line service valves, crankcase heater and inherent solid state thermal overload protection. Each compressor shall have its own completely independent refrigeration circuit including sight-glass, filter-drier, manual shut-off valve and spring-type high pressure relief valve. Compressors shall be isolated on (neoprene impregnated glass fiber kinetic blocks) (spring mounts with vibration line isolators). Compressor capacity reduction shall be accomplished with cylinder unloading and/or hot gas bypass. 1. Hot gas bypass control shall be factory installed on each compressor circuit to provide capacity control by artificially loading the evaporator. Hot gas bypass control shall include a solenoid valve, hot gas bypass piping, and a hot gas bypass valve. The hot gas bypass valve shall be sized to modulate the full load. 2. Additional steps of cylinder unloading shall be provided on multiple compressor and single six-cylinder compressor units. Suction pressure switches shall control the cylinder unloaders on units with wall thermostat or return air temperature control. A unit mounted step controller shall control the cylinder unloaders electrically on units with discharge air temperature control. 3. An adjustable 0 to 8 minute timer lockout shall be provided on each compressor to prevent short cycling on safety control or power interruption. C. The evaporator coil circuitings shall be fed with an adjustable thermal expansion valve (one per refrigerant circuit) with an external equalizer. The evaporator coil shall be circuited for a combination row/face split on two (2) compressor units. D. The condensing unit section shall be open on the sides and bottom to assure complete access to and airflow through the coils. Condenser coils shall be multi-row type fabricated from seamless copper tubing mechanically bonded to rippled and corrugated aluminum fins. Condenser coil for each refrigerant circuit shall be provided with an additional circuit for a minimum of 15 degrees of subcooling. Each condenser coil shall be factory leak tested at 315 psig under water. E. Condenser fans shall be direct drive, propeller type designed for low tip speed and vertical air discharge. Fan blades shall be constructed of steel and riveted to a rust inhibited steel center hub. F. Condenser fan motors shall be heavy-duty, inherently protected, three-phase non-reversing type with permanently lubricated ball bearings and integral rain shield. Page 18 of 28