Minneapolis Public Schools



SECTION 23 75 13CUSTOM PACKAGED, OUTDOOR, CENTRAL-ROOFTOP UNITS - GENERALSUMMARYSection Includes: Include labor, materials, equipment, and accessories necessary to furnish and install a factory assembled and tested custom packaged, outdoor, central-station air handling units to include an energy wheel, air-to-air heat exchanger, supply air and exhaust air blowers, motors with starters and relays, air filters, and specified options as shown on Drawings and specified.QUALITY ASSURANCECode Regulatory Requirements:State Building CodeLocal Codes and OrdinancesLocal Authority having jurisdictionAMCA Compliance:Certify airflow measurement station performance in accordance with AMCA 611.AHRI Compliance:For air coils, certify capacities, pressure drops, and selection procedures in accordance with current AHRI Standard 410.Air handling units with fan sections utilizing single fans shall be rated and certified in accordance with AHRI Standard.Air handling units with fan sections utilizing multiple fans shall be rated in accordance with AHRI Standard 430 for airflow, static pressure, and fan speed performance.NFPA Compliance: Provide air handling unit internal insulation having flame spread rating not over 25 and smoke developed rating no higher than 50, meeting the requirements of NFPA 90A, Standard for the Installation of Air Conditioning and Ventilating Systems.UL and NEMA Compliance: Provide electrical components required as part of air handling units which have been listed and labeled by UL and meet the requirements of NEMA Standards.Special Quality Assurance Requirements:The following are to be used as selection criteria and are to be as specified: Airflow rates, external static pressures, and water flow rates. The following are to be equal or better: Coil face velocities, filter face velocities, casing leakage rates, casing, and base deflection. The following are to be met within 10 percent of specified values: Water pressure drops.Coil face velocities shall not exceed 530 feet per minute.Units with factory wiring shall be factory UL/ETL/CSA approved and labeled. Failure to comply with this requirement shall necessitate the manufacturer at its expense to have a certified UL/ETL/CSA representative inspect the equipment prior to affixing a label.SUBMITTALSGeneral: Provide submittals in accordance with Section 01 33 00. No equipment shall be fabricated or delivered until the receipt of approved Shop Drawings from the Owner or Owner's approved representative.Shop Drawing/Product Data: Provide all technical information relevant to the product being provided, including but not limited to, all the information in this Specification. It is the responsibility of the supplier to highlight any variances that its equipment has with the requirements of this Specification, whether or not pre-approval has been obtained. Provide the information in the same measurement units as indicated elsewhere in this Specification. Provide Product Data for each air handled unit specified, including the following:Certified Fan Performance Curves; provide fan curves (not fan tables) with specified operating points clearly plotted. Data shall be corrected to actual operating conditions, temperatures, and altitudes.For units utilizing multiple fans in a fan section, a fan curve shall be provided showing the performance of the entire bank of fans at design conditions. In addition, a fan curve shall be provided showing the performance of each individual fan in the bank of fans at design conditions. A fan curve shall be provided showing the performance of the bank of fans, if one fan is down. The percent redundancy of the bank of fans with one fan down shall be noted on the fan curve or in the tabulated fan data.Sound Data Certified to AHRI 260; include sound attenuators, when scheduled, with manufacturer's sound rating in dB in each octave band at design conditions. Submit sound power levels for both air handling unit inlet, outlet and radiated at rated capacity. If unit exceeds sound power levels at scheduled conditions, manufacturer must provide sound attenuators and meet specified BHP.Certified Coil Performance Ratings; with system operating conditions indicated. Indicate coil tube fin and casing construction.Motor Ratings and Electrical Characteristics; with electrical requirements for power supply wiring including wiring diagrams for interlock and control wiring, clearly indicating factory installed and field installed wiring.Casing and Frame Materials, Gauges, and Finishes.Dampers; with performance ratings and including housings, linkages, and operators. Applications involving field mounted actuators, refer to specification section 23 09 00. The dampers shall be provided with factory hardware suitable for mounting of MPS approved actuators. Filters; indicating initial APD, final APD, dust spot efficiency, MERV rating, final dust holding capacity, filter media description, filter frame details and filter removal details.A filter schedule must be provided for each air handling unit supplied by the air handling unit manufacturer. Schedule shall detail unit tag, unit size, corresponding filter section location within the AHU, filter arrangement (e.g. angled/flat), filter depth, filter type (e.g. pleated media), MERV rating, and filter quantity and size.Dimensioned Arrangement Drawings for Each AHU; including a plan and elevation view of the assembled unit with overall dimensions, lift points, unit shipping split locations and dimensions, installation and operating weights, and installation, operation, and service clearances.Electrical, Piping, and Ductwork Requirements; including sizes, connection locations, and connection method recommendations.Each component of the unit shall be identified and mechanical specifications shall be provided for unit and accessories describing construction, components, and options.All Performance Data; including capacities and airside and waterside pressure drops for components.Schedule; detailing necessary trap height shall be provided for each air handling unit. Schedule shall detail unit tag, unit size, appropriate trap schematic with recommended trap dimensions, and unit supplied base rail height. Contractor shall be responsible for additional trap height required for trapping and insulation beyond the unit supplied base rail height by adequate housekeeping pad.Electrical MCA - MOP Schedule; shall be provided for each electrical circuit to which field-power must be supplied. Schedule to detail unit tag, circuit description, voltage/phase/hertz, Minimum Circuit Ampacity (MCA), and calculated Maximum Overcurrent Protection (MOP).Omission of any of the above information will cause Shop Drawings to be immediately returned without review.Coordination Drawings: Drawings for air handling units in accordance with Section 23 00 00, Heating, Ventilating, and Air-Conditioning (HVAC) - General Requirements. Submit with Shop Drawings:Show air handling unit floor plans and section drawn accurately to scale.Show internal air handling unit components. Indicate dimensions between individual components and air handling unit casings.Show mechanical room layout and relationship between components and adjacent structural and mechanical elements. Show required service clearances, including coil removal spaces.Show support locations, type of support, and weight on each support.Show concrete base layouts and locations. Indicate dimensions to structural walls or columns for accurate field placement. Indicate required rough-ins for piping, including floor drains, and electrical conduits.Indicate and certify field measurements.Wiring Diagrams: Wiring diagrams detailing wiring for power and controls, and differentiating between manufacturer-installed wiring and field-installed wiring.Maintenance Data: Maintenance Data for air handling units to be included in the Operating and Maintenance Manual specified in Division 1 and Section 23 01 00, Operation and Maintenance of HVAC Systems.Miscellaneous:Field installation and assembly instructions for air handling unit casing and internal components.Field test reports indicating and interpreting test results relative to compliance with specified requirements.Field fabrication of components is prohibited, unless addressed in the Specifications within this Section.Submit data on electrical requirements. Include safety and start-up instructions.REGULATOR REQUIREMENTSAgency Listings/Certifications:Unit shall be manufactured to meet the requirements of UL 1995 and shall be listed by either UL/CUL or ETL. Units shall be provided with listing agency label affixed to the unit. In the event the unit is not UL/CUL or ETL approved, Contractor shall, at its expense, provide for a field inspection by a UL/CUL or ETL representative to verify conformance. If necessary, Contractor shall perform modifications to the unit to comply with UL/CUL or ETL as directed by the representative, at no additional expense to Owner.Certify air handling units in accordance with AHRI Standard 430. Units shall be provided with certification label affixed to the unit. If air handling units are not certified in accordance with AHRI Standard 430, Contractor shall be responsible for expenses associated with testing of units after installation to verify performance of fan(s). Any costs incurred to adjust fans to meet scheduled capacities shall be the sole responsibility of the Contractor.Certify air handling coils in accordance with AHRI Standard 410. Units shall be provided with certification label affixed to the unit. If air handling coils are not certified in accordance with AHRI Standard 410, Contractor shall be responsible for expenses associated with testing of coils after installation to verify performance of coil(s). Any costs incurred to adjust coils to meet scheduled capacities shall be the sole responsibility of the Contractor.Certify airflow monitoring stations are tested for differential pressure in accordance with AMCA 611 in an AMCA registered laboratory and meet the requirements of the AMCA Certified Ratings Program. Airflow monitoring station shall be licensed to bear the AMCA seal.DELIVERY, STORAGE, AND HANDLINGGeneral: In accordance with manufacturer's installation instructions for rigging, unloading, and transporting units.Shipping: Units shall ship fully assembled up to practical shipping and rigging limitations with protective crating and covering. Disassemble and reassemble units as required for movement into the final location following manufacturer's written instructions. Units not shipped fully assembled shall have tags and airflow arrows on each section to indicate location and orientation in direction of airflow. Shipping splits shall be clearly defined on submittal drawings. Cost associated with non-conformance to Shop Drawings shall be the responsibility of the manufacturer. Each section shall have lifting lugs for field rigging, lifting, and final placement of air handling unit section(s). Air handling units less than 100 inches wide shall allow for forklift transport and maneuverability on the site. Lift and support units with the manufacturer's designated lifting or supporting points. Notify project team of delivery and crane dates. Special shipping requirements are as follows in order to fit through existing building arrangements:Delivery: Deliver units to site with fan motor(s), sheave(s), and belt(s) completely assembled and mounted in units.Protection:Manufacturer of unit shall ship unit in a clear shrink-wrap or stretch-wrap to protect unit from in-transit rain and debris in accordance with ASHRAE 62.1 recommendations.Installing contractor shall be responsible for storing AHU in a clean, dry place and protect from weather and construction traffic. Handle carefully to avoid damage to components, enclosures, and finish. Use extraordinary means to ensure units are turned over to the Owner in like-new condition, clean and undamaged.PROJECT CONDITIONSField Measurements: Verify dimensions by field measurements and clearances.Cleaning: Do not operate fans until ductwork is clean, filters are in place, bearings are lubricated, and fans have been commissioned.SEQUENCING AND SCHEDULINGCoordination: Coordinate the size and location of concrete equipment bases. Cast anchor bolt inserts into pad. Concrete reinforcement and formwork requirements are specified under Division 3 sections.EXTRA MATERIALSGeneral: Furnish extra materials described below that match products installed, are packaged with protective coverings for storage, and are identified with labels describing contents.Furnish (1) extra set of filters for each air handling unit.Furnish (1) extra set of fan belts for each air handling unit fan.Furnish (1) extra set gaskets for each sectional joint for each air handling unit.START-UP AND OPERATING REQUIREMENTSGeneral: Do not operate units for any purpose, temporary or permanent, until ductwork is clean, until building is clean, filters in place, bearings lubricated (if applicable), condensate properly trapped, piping connections verified and leak-tested, belts aligned and tensioned, all shipping braces removed, bearing set screws torqued, and fan has been test run under observation.WARRANTYDescription: Equipment manufacturer shall provide, at no additional cost, a standard parts warranty. This warrants that all products are free from defects in material and workmanship, and shall meet the capacities and ratings set forth in the equipment manufacturer's catalog and bulletins. - PRODUCTSMANUFACTURERSAcceptable Manufacturers for Custom Rooftop Unit: Subject to compliance with requirements of the Contract Documents, acceptable manufacturers are as follows:InnoventTrane Performance Climate Changer / TCFSSeasons FourAcceptable Manufacturers for Energy Wheels: Subject to compliance with requirements of the Contract Documents, acceptable manufacturers are as follows:SemcoRotosourceDiakinAcceptable Manufacturers for Air-to-Air Heat Exchangers: Subject to compliance with requirements of the Contract Documents, acceptable manufacturers are as follows:SemcoRotosourceDiakinAcceptable Manufacturers for all Air Cooled Condensing Unit Cottonwood Screening: Subject to compliance with requirements of the Contract Documents, acceptable manufacturers are as follows or Owner approved equal:Permatron: model BHATrane: Air SolutionsHeavy duty, single ply, non-porous, non-electrostatic HVAC mesh, UV resistant vinyl coating over a polyester fiber core fiber reinforced outer binding.Mesh shall have a rip stop characteristic using a coating bond at intersect points to prevent tearing and running in the event of a cut or puncture.Filters include a fiber reinforced vinyl outer binding wrapped on all sides providing a 1.125 mounting face and back binding with two rows of double lock stitching which is UV and weather resistant.Heavy duty rust proof grommets.A type of quick release toggle fasteners with mounting screws.No tools shall be needed for screen installation or removal for maintenance.No Velcro for fastening allowed other than at pipe penetrations where the filter media goes around the pipe.Must be custom sized to fit around pipe penetrations.Cut to fit and fastened with zip ties or any other temporary means is not allowed.Additional Acceptable Manufacturers Requirements:Manufacturers not pre-approved, must obtain pre-approval in writing from consulting Engineer prior to Bid Date. Alternates shall comply with all performance and features as called for in this Specification.Manufacturer shall clearly define any exceptions made to Drawings and Specifications. Any deviations in layout or arrangement shall be submitted to consulting Engineer prior to Bid Date. Acceptance of deviation(s) from Specifications shall be in the form of written approval from the consulting Engineer. Mechanical Contractor is responsible for expenses that occur due to exceptions made.CABINET CONSTRUCTIONWelded Structural Steel Base Frame and Floor:Unit shall have an all-welded base frame constructed from structural steel. The frame shall include formed supports constructed from welded structural steel under blowers and other components.Base frame shall incorporate a minimum of (4) integral lifting lugs for every separate unit section.A 16 gauge galvanized steel interior floor shall be installed on the base frame. The floor shall be insulated and a 22 gauge galvanized steel sub-floor shall be installed under the insulation.Floor insulation shall be 2 inches thick and consist of a load-bearing, rigid, closed-cell polyiso foam core laminated to a black glass reinforced mat facer. Insulation blowing agents shall be HCFC-free and qualify under the Federal Procurement Regulation for Recycled Material. Additionally, insulation shall meet the following criteria:Insulation shall have an LTTR R-Value of 12.1 (where the LTTR is based on a 15-year time weighted average in accordance with CAN/ULC-S770).Insulation shall have a compressive strength of 20 psi under ASTM D1621, a density of 2 pcf under ASTM D1622, a dimensional stability of less than 2 percent under ASTM D2126, a moisture vapor transmission of less than 1 perm under ASTM E96, and a water absorption of less than 1 percent by volume under ASTM C209. Insulation shall have a service temperature of minus 100 degrees F to plus 250 degrees F.Insulation shall be compliant with the following specifications: ASTM C1289, Type II, Class 1; UL classified; FM Class 1 approved; and CAN/ULC-S704. Additionally, the manufacturer's facility shall be ISO 9002 registered.All seams in the base frame shall be sealed, and the frame shall be coated with a rust inhibiting paint. The perimeter of the frame shall be insulated.Drain Pans:Drain pans shall be provided in all cooling coil, humidifier, and heat exchanger sections where condensate might be present.Drain pans shall be double sloped, have all welded seams, MPT connections, and be constructed from Type 304 stainless steel. Drain pans with a bitumastic coating are not acceptable because of their poor durability.Cooling coil sections will have Type 304 stainless steel drain pans, double sloped with MPT connections.Hinged Access Doors:Access to all exchanger surfaces, blowers, motors, filters, and other components requiring regular maintenance shall be provided through hinged access doors.Access doors shall have double-wall construction with 18 gauge (minimum) galvanized steel inner and outer walls and 3-pound density hardboard fiberglass insulation. Access door construction shall be otherwise consistent with the unit panel and frame.Access doors shall be held closed by a minimum of (2) roller cam latches. Door hinges shall be galvanized steel. Doors shall be removable from the unit frame.Access door frames shall be made from galvanized steel. Continuous hollow rubber gasket shall be applied to all access openings to provide water and airtight seals.Acoustical Performance:Acoustical performance of cabinet panels shall be tested by an accredited independent laboratory under the ASTM E90 and E1332 standards and have a certified STC rating of 39 for 2-inch walls and an OITC rating of 27 for 2-inch walls.Sound absorption data is not an acceptable substitute for OITC rating data. Manufacturer shall provide a testing report from the accredited independent laboratory and transmission loss data upon request.Acoustical performance shall be as follows:Transmission Loss: ASTM E90(04) and E413(4) Hz 80 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2" Walls 15 15 18 18 33 36 39 42 42 46 51 54 56 57 4" Walls 12 20 28 29 39 41 43 45 46 49 53 55 56 56 Hz20002500315040002" Walls626669704" Walls61646667Perforated panels shall be installed on the walls of all blower sections to provide additional acoustical insulation.Double Wall Construction:Cabinet frame exterior shall be of formed 18 gauge (minimum) galvanized steel. Panels (fixed and access) to be of 18 gauge galvanized steel.Frame and panels to be double-walled construction with 2-inch thick insulation. Insulation shall be 3-pound density hardboard, composed of glass fibers bonded with a thermoset resin and faced with an adhered black non-woven mat surface, and meet the following criteria:Insulation shall have a thermal resistance R factor of 2-inch thick: 8.7Insulation shall meet the requirements of ASTM 612, Type 1A and 1B. Under ASTM E84, it shall have a maximum flame spread index of 25 and a maximum smoke developed index of 50; under NFPA 259, its limited combustible rating shall be less than or equal to 3,500 BTU per pound.Insulation shall have received a rating of “pass” under the following tests: the ASTM C665 corrosiveness test, the ASTM C1338 test for fungi resistance, and the ASTM C1304 test for odor emission.Insulation shall be UL listed and the manufacturer's plant shall be ISO 9001 registered.Urethane foam insulation is not acceptable.Frame and panels to have an internal liner of 22 gauge (minimum) galvanized steel and be sealed with silicone sealant to provide a complete vapor barrier and non-contaminating surface to all air streams. Unit return air plenum and supply discharge shall have a galvanized perforated inner liner.Rooftop/Outdoor Construction Options:Weatherized outdoor construction shall include sloped roof panels with rain gutters that overhang the sidewalls to shed water away from access panels, capped roof seams, outside air shut-off damper, exhaust air shut-off damper, and intake and exhaust weather hoods with bird screens. Secondary roof panels that could trap moisture are not allowed.24-inch high roof curb shall be 16 gauge (minimum) galvanized steel with additional supports and cross members as needed. Curb to have wood nailer and 1.5-inch thick fiberglass insulation of the same type used to insulate the unit floor.Condenser Coil - Cottonwood Screen / Hail Protection. Field Install a cottonwood screen.Unit Finish:Unit exterior shall be constructed from galvanealed steel and primed with industrial Pro-Cryl universal primer. Primer shall be a single component cross-linking acrylic and designed for construction applications. It shall further be VOC compliant, rust inhibitive, and early moisture and corrosion resistant.Primer shall be applied to a thickness of 5.0 to 10.0 wet mils, 2.0 to 4.0 dry mils.A top coat of Sher-Cryl HPA high performance acrylic shall be painted over the primer. The top coat shall be an ambient cured, single component acrylic coating. It shall be chemical, flash and rust, and corrosion coat shall be applied to a thickness of 6.0 to 10.0 wet mils, 2.5 to 4.0 dry mils.Exterior finish shall meet the following performance requirements: Flexibility Moisture Condensation Resistance Pencil Hardness Salt Fog Resistance ASTM D522, 180E bend, 1/4" mandrel ASTM D4585, 100EF, 1250 hours ASTM D3363 ASTM B117,1250 hours Pass Pass H Pass Test: Adhesion Corrosion Weathering Direct Impact Resistance Dry Heat Resistance Method: ASTM D4541 ASTM D5894, 10 Cycles, 3360 hours ASTM D2794 ASTM D2485 Result: 500 psi Pass > 140 in. lbs. 200EFExterior finish shall provide performance comparable to products formulated to Federal Specification AA50570/AA50557 and Paint Specification SSPC-Paint 23.Unit interior finish shall be G90 galvanized steel.Unit return air plenum and SA discharge plenum will have a galvanized perforated inner liner.ENERGY WHEEL SECTIONGeneral Requirements:Air handling unit shall have a total energy wheel sized in accordance with the ventilation requirement as defined on the schedule. The energy wheel shall be an integral part of the air handling unit. Unit shall be installed as a complete system with no additional outside air unit, or other field assembled and ducted energy recovery device. Manufacturer shall include performance information in the submittal that meets or exceeds scheduled wheel performance.Energy wheel shall be sized to handle minimum outside air ventilation requirement as defined on schedule. Energy wheel section shall be capable of 100 percent economizing. Wheel section shall include variable effectiveness damper. On mixed air units, the return damper shall be an integral part of the energy wheel section and shall be sized for adequate mixed air control.Rotor media shall be made of corrugated and flat aluminum sheet material or corrugated synthetic fibrous media which is coated to prohibit corrosion; etched or oxidized surfaces are not acceptable. All surfaces shall be coated with a non-migrating absorbent desiccant specifically developed for the selective transfer of water vapor. Verification in writing shall be presented from the desiccant manufacturer confirming that the internal pore diameter distribution inherent in the desiccant being provided, limits absorption to materials not larger than the critical diameter of a water molecule (4.O angstroms).Air handling unit shall be certified by ARI to contain a rotary energy recovery wheel that is ARI 1060 certified. The air handling unit nameplate shall bear the ARI 1060 certification label. Performance characteristics of the energy wheel shall be provided as defined by ARI 1060. The energy wheel shall be an enthalpy wheel capable of sensible and latent heat transfer. Sensible, latent, and total net effectiveness of the wheel performance shall meet or exceed performance as defined on schedule. The calculated total net effectiveness of the recovery device shall not be less than 70 percent when the specified ventilation flow rate equals the exhaust flow rate. Wheel face velocity and pressure drop shall not exceed performance as defined on schedule. The energy recovery cassette shall be a UL recognized component certified for mechanical, electrical, and fire safety in accordance with UL Standard 1812.Total energy wheel casing shall be constructed in accordance with paragraphs "Unit Casing". Insulation shall be in accordance with paragraphs "Unit Casing".Energy recovery component shall incorporate a rotary wheel in an insulated cassette frame complete with seals, drive motor, and drive belts. The total energy recovery wheel shall incorporate a desiccant without the use of binders or adhesives, which may plug the desiccant aperture. The rim shall be continuous rolled stainless steel to form an even concentric circle to prevent leakage around the rim and to minimize wear of components. All diameter and perimeter seals shall be provided as part of the cassette assembly. Perimeter seals shall be self-adjusting; diameter seals shall be adjustable. Seals shall be factory set. Wheel bearings shall be permanently sealed and lubricated and have a minimum L-10 life of 400,000 hours.Wheel drive motor shall be provided, mounted in the cassette frame, and supplied with a connector for field service. The wheel drive motor shall be thermally protected and UL recognized component. On units that require drive belt tensioners for the wheel belt/motor assembly, the wheel manufacturer shall provide, at no additional charge to the Owner, a visual inspection every (4) months, and adjustment if necessary, of the recommended belt tension during the unit warranty period.Speed Control Panel: Refer to Section 23 05 14.Dampers: Wheel section shall include bypass dampers in the supply and exhaust sections and a return damper between the supply and exhaust sections downstream of the supply side of the wheel. Refer to Drawings. Applications involving field mounted actuators, refer to specification section 23 09 00. The dampers shall be provided with factory hardware suitable for mounting of MPS approved actuators. Energy recovery media for wheels larger than 25 inches in diameter shall be provided in the form of removable segments. The segments shall be removable without the use of tools to facilitate maintenance and cleaning as required. Coated segments shall be washable using standard detergent or alkaline-based coil cleaners. The desiccant shall not dissolve in the presence of water or high humidity.Unit shall be provided with a factory set, field adjustable purge sector designed to limit cross contamination to less than 0.04 percent of that of the exhaust airstream concentration when operated under appropriate design conditions.Access doors shall be provided on all air entering and air leaving sides of wheel to allow for wheel maintenance, belt or motor removal. Access doors shall be constructed in accordance with paragraphs "Unit Casing".AIR-TO-AIR ROTARY HEAT EXCHANGER SECTIONGeneral Requirements:Heat exchanger shall be a cross flow, aluminum, plate type exchanger. The aluminum plates shall be die formed from 99.9 percent pure aluminum with a plate profile that maximizes efficiency and cleanability, and minimizes pressure loss. The connection plate edges shall be double-folded and sealed internally with a synthetic resin. The plate core shall be assembled into a strong, self-supporting frame made of aluminum corner extrusions and galvanized steel end plates. Access to all (4) sides of the exchanger for cleaning and inspection shall be provided.Air handling unit shall be configured to allow for inspection and cleaning of all (4) air paths of plate heat exchanger.Heat exchanger section shall be constructed in accordance with paragraphs "Unit Casing". Unit casing shall be double wall construction and insulated in accordance with paragraphs "Unit Casing".Heat exchanger shall meet the performance as shown on the schedule. No frost control or bypass dampers are required.BLOWERS, MOTORS, AND MOUNTSBackward Inclined (BI) Double Width Double Inlet (DWDI) Air Foil (AF) BlowerSupply and exhaust air blowers shall be a backward inclined airfoil centrifugal DWDI type designed with scroll type housing in a draw-through configuration. Fans shall incorporate a wheel, heavy gauge reinforced steel inlet plate shaft, and bearings in AMCA Arrangement 3 configuration to form a heavy-duty integral unit. Blowers shall be tested to AMCA Standard 210 and bear the AMCA certified ratings seal for performance.Fan blades shall be continuously welded, die-formed airfoil type, designed for maximum efficiency and quiet operation. Impellers shall be statically and dynamically balanced, non-overloading, and complete fan assembly shall be test balanced at the operating speed prior to shipment.Shafts are to be sized for first critical speed of at least 120 percent, the maximum speed for the class.Bearings are to be heavy duty, grease lubricated, and selected for minimum average bearing L-10 life of 40,000 hours optional, L-50 life of 200,000 hours at the maximum class rpm.Provide grease tube extensions (copper) extended to the exterior of the cabinet.Fan motors shall be premium efficient, ODP T-frame, 1,750 rpm nominal with minimum service factor of 1.15, mounted on an adjustable base.Motor and blower are to be mounted on common frame and isolated from unit case with spring isolators with a minimum of 1-inch deflection with flexible duct connections.Motors and blowers shall be direct drive.Motors, blowers, and frames shall be coated with rust inhibiting paint.COILSGeneral Requirements:Casings shall be constructed of continuous galvanized steel.Coil side plates shall be reinforced flange type for greater strength and ease of stacking and shall have 3/8-inh holes on 6-inch centers for mounting.Full length fin channels shall be furnished to brace the coil core and prevent air bypass.Primary surface shall be round, seamless copper tubing brazed into intruded header tube holes using brazing alloys.Secondary surface shall consist of rippled-corrugated aluminum plate fins for higher capacity and strength.Low efficiency flat plate fins will not be acceptable.Fins shall have full drawn collars to provide a continuous surface cover over the entire tube.Fins shall not have sharp edges that accumulate dirt.Bare copper tube shall not be visible between fins.Tubes shall be expanded into fins to provide a continuous primary to secondary compression bond over the entire finned length, for maximum heat transfer rates.Hot Water Coils:Headers shall be of non-ferrous materials using seamless copper tubing with intruded tube holes to permit expansion and contraction without creating undue stress or strain.Rolled-in joints or dissimilar metals will not be acceptable.Bent connections shall be provided at the highest point to ensure proper venting.Coils shall have connections provided for universal right- or left- handed airflow applications.Coils shall be circuited to provide the maximum mean effective temperature difference for maximum heat transfer rates.The use of internal restrictive devices to obtain turbulent flow will not be acceptable since they prevent complete draining of the coil and give high water pressure drop.All coils exceeding 45-inch FL shall be furnished with (4) fin angles to properly position the coil plete coil core shall be tested with 315-pounds air pressure under warm water and guaranteed for 250 psig working pressures.Individual tube and core testing before installation of the header is not considered satisfactory. Hydrostatic tests alone will not be acceptable.DX Coil:Coils shall have connections provided for universal right- or left- handed airflow applications.Coils shall be circuited in a counter-flow manner to provide the maximum mean effective temperature difference for maximum heat transfer rates.All coils exceeding 45-inch FL shall be furnished with (4) fin angles to properly position the coil plete coil core shall be tested with 315-pounds air pressure under warm water and guaranteed for 250 psig working pressures.Hydrostatic tests alone will not be acceptable.Coils shall be dehydrated with 140 degree F DB, 40 degree F dewpoint air before shipment.Coils shall be ARI certified and UL listed.Unit shall have welded stainless steel drain pans under DX coils and dehumidification section that are sloped to provide positive drainage.AIR COOLED CONDENSING UNITGeneral Requirements: Condensing section shall be an integral part of the unit and include (1) or more sealed refrigerant circuits, including a hermitic motor-compressor, thermal expansion valve, bypass valves, finned tube air-to-refrigerant heat exchanger, crank case heaters, filter driers, and service ports.All condenser coils shall come equipped with cottonwood pressor:Secondary 7.5-ton compressor shall be high-efficient 'Copeland' fixed scroll type for 410A refrigerant and mounted on neoprene vibration isolators.Lead 10-ton compressor shall be 'Copeland' digital inverter scroll type for 410A refrigerant and mounted on neoprene vibration isolators. Compressor capacity shall be capable of modulation between 10 and 100 percent of full capacity to provide better dehumidification, reduce compressor cycling, and decrease the starting electrical load. Modulation shall be achieved by axially separating and unloading the scroll members. This separation shall be effected by bypassing a controlled amount of discharge gas to the suction side through a solenoid valve, thereby lowering the pressure in the modulating chamber. No pumping action shall be required to achieve the modulation.Safety Controls: Safety controls shall include an anti-short cycle timer and high and low refrigerant pressure switches for protection against loss of charge and extreme low temperature operation.Wiring and Plumbing: All wiring and plumbing shall be completed at the factory so that the unit, as shipped, contains a complete refrigeration package.Condenser Fans:Fans shall be propeller type with aluminum blades and painted steel hubs.Fans shall be dynamically balanced and factory run tested.Motors to be heavy duty, 3 phase, open drip proof, with built in overload protection and permanently lubricated bearings.Fan guards shall be made of heavy gauge steel wire.FILTERSGeneral Requirements:Provide factory fabricated filter section of the same construction and finish as unit casings. Filter section shall have side access filter guides and access door(s) extending the full height of the casing to facilitate filter removal. Provide fixed filter blockoffs as required to prevent air bypass around filters. Blockoffs shall not need to be removed during filter replacement.Filter type, MERV rating, and arrangement shall be provided as defined in Project Drawings and schedule.Filter Gauges:Provide Dwyer 2000 (photohelic) magnehelic gauges.Magnehelic gauges shall be accurate to plus 2 percent of full range.Include static pressure tips.One gauge shall be provided for each filter bank.Gauges shall be recessed into cabinet casing.Filter sections consisting of pre- and post-filters shall have a gauge for each.To allow MPS to standardize on filter sizes for all AHUs, filter sizes shall be consistent and based on full 24-inch by 24-inch or half 12-inch by 24-inch sizes. Other sized filters are not acceptable.Quantity of Filters: At time of Substantial Completion, and prior to turning equipment over to Owner, Contractor shall install a complete set of unused, clean filters (pre-filter and final filter) in each unit supplying filtered air to the building. Provide (2) sets of pre-filters (one during construction and one for Owner at Substantial Completion).Pre-Filters:Pre-filters shall be 30 percent efficient, MERV 8 pleated, disposable type. Each filter shall consist of a non-woven cotton and synthetic fabric media, media support grid and enclosing frame. The filter shall be listed by Underwriters' Laboratories as Class 2.Pre-filters shall be installed in prefabricated channel rack.Pre-filters shall be lift-out where access is available upstream of the filter.Final Filters:Final filters shall be high performance, deep pleated, totally rigid and disposable type. Each filter shall consist of high density microfine glass fiber media, media support grid, contour stabilizer, and enclosing frame.Final filter media shall be of high density microfine glass fibers that are laminated to a non-woven synthetic backing to form a lofted filter blanket. The filter media shall have an average efficiency of 60 to 65 percent on the ASHRAE Test Standard (52 to 76) and a MERV 11 rating. Filter media shall have an average arrestance of not less than 99 percent on that standard. Filters shall be listed by Underwriters' Laboratories as Class 2.Holding Frames: ASHRAE Holding frames shall be factory fabricated of 16 gauge galvanized steel and shall be equipped with gaskets on all (4) sides of the filter and (2) heavy duty positive sealing fasteners. Each fastener shall be capable of withstanding 25-pound pressure without deflection and be attached or removed without the use of tools.Final filters shall lift out where access is available upstream of the filter.DAMPERSGeneral Requirements: All dampers, with the exception of external bypass and multi-zones (if scheduled), shall be internally mounted. Dampers shall be premium ultra low leak and located as scheduled. Dampers shall be Ruskin CD60 double-skin airfoil design or equivalent for minimal air leakage and pressure drop. Leakage rate shall not exceed 5 cfm per square foot at 1-inch water gauge and 9 cfm per square foot at 4-inch water gauge. All leakage testing and pressure ratings shall be based on AMCA Publication 500. Manufacturer shall submit brand and model of damper(s) being furnished. Applications involving field mounted actuators, the dampers shall be provided with factory hardware suitable for mounting of MPS approved actuators. Face and Bypass Dampers: Provide internal face and bypass dampers with each unit using preheat coils. Provide an access spacer section, 18-inch minimum, between preheat coil and unit coil sections.Outside Bypass, Exhaust Bypass, and Return Air Dampers: Dampers shall be provided to modulate the volume of outside, exhaust, and return air. Damper blades shall be galvanized steel, housed in a galvanized steel frame and mechanically fastened to an axle rod rotating on bearings. Blade seals shall be required to assure tight closure. Dampers shall be rated for a maximum leakage rate of 5 cfm per square foot at 1-inch water gauge.Multi-Zone Dampers: Multi-zone units damper section shall have 16 gauge, galvanized die-formed damper blades bolted to a full length electro-linked rod. Align operating crank arms and damper blades for proper operation. Damper blade stops shall be foam plastic seals.Zone dampers shall be provided by the unit manufacturer with both hot and cold deck damper blade openings completely gasketed for positive seal. Damper shafts shall rotate freely on rust-proof nylon bushings. Interior zone ducts shall be easily attached to zone dampers using duct clips provided by manufacturer.Provide an access spacer section for damper access.ELECTRICALGeneral Requirements: Electrical controls shall include, for direct drive units, motors with internal thermal protection and relays fused branch circuit breakers, control transformer for low voltage controls, service switch, and terminal points/blocks all contained in a NEMA 3R, unit-mounted control panel.Disconnect Switch: A single main disconnect switch for single point power connection shall be provided. The disconnect switch shall be mounted through the access panel so that power will have to be shut-off before the access door can be opened.Circuits: Motor power and branch circuits shall be protected by circuit breakers so replaceable fuses will not be necessary.Wiring and Controls: All provided wiring and controls shall be factory tested before shipment.Wiring Diagram: Unit wiring diagram shall be provided in the panel.Electrical Lights and 115 Volt Receptacle: Unit fan section shall be provided with an overhead heavy duty light supported from the ceiling. Unit light shall be wired through electrical conduit to a weatherproof junction box, located near the motor electrical wiring junction box.Weatherproof box shall contain a weatherproof light switch and 115 volt convenience outlet wired in accordance with state and local codes.Units larger than 8 feet in width must have (2) lights in the fan section, to permit viewing of supply fan bearing operations.VFD: VFDs are provided by Division 26 as indicated in Section 26 29 23. Provide space in unit for field installation of the VFDs.CONTROLSGeneral Requirements: Refer to Section 23 09 00, Building Management System, for control sequence provided by BMS Contractor.A direct digital controller for the air handling units shall be furnished and installed by the installing contractor=s Control Subcontractor (under separate Contract). Controller shall be a microprocessor based, multi-tasking, real time, stand alone controller capable of performing its specified control sequence.MOTORS AND DRIVESGeneral Requirements:All motors and drives shall be factory installed and run tested. All motors shall be installed on a slide base to permit adjustment of belt tension. Slide base shall be designed to accept all motor sizes offered by the air handler manufacturer for that fan size to allow a motor change in the future, should airflow requirements change. Fan sections without factory-installed motors shall have motors field installed by the Contractor. The Contractor shall be responsible for all costs associated with installation of motor and drive, alignment of sheaves and belts, run testing of the motor, and balancing of the assembly.Fan motors shall be heavy duty, open drip-proof (ODP) high efficiency.Motors shall be selected to operate continuously at 104 degrees F (40 degrees C) ambient without tripping of overloads. Motors shall have a plus/minus 10 percent voltage utilization range to protect against voltage variation. Motors shall be in compliance with EPACT when applicable.Motors shall be of an energy efficient design (refer to Section 23 05 13 for motor minimum efficiency). Refer to Section 23 05 13, Electric Motor Schedule, or the Equipment Schedule for voltage and rpm requirements.On fans that have a variable frequency drive, provided factory mounted motor shaft ground system and the motor shall be invertor duty type motor.V-Belt drive shall be constant pitch rated at 1.2 times the motor nameplate. Refer to synchronous drive detail requirements.Manufacturer shall provide for each fan a nameplate with the following information to assist Air Balance Contractor in start up and service personnel in maintenance:Fan and Motor Sheave Part NumberFan and Motor Bushing Part NumberNumber of Belts and Belt Part NumbersFan Design RPM and Motor HorsepowerBelt Tension and DeflectionCenter Distance Between ShaftsContractor shall provide and install synchronous drive packages on fans which are at least 10 horsepower and controlled by means of a VFD or other means of soft start. Drive selection shall be sized after preliminary TAB work has established unit preliminary cfm. No additional cost shall be incurred by Owner.Provide belt guards that meet OSHA requirements.Contractor shall provide (1) additional drive pulley with installation and labor per air handling unit. Performance rating shall be selected and correct size pulley shall be installed following system installation, and running check and balance. Contractor shall retain drive pulley not used.ACCESSORIESHot Gas Bypass: Permits continuous, stable operation at capacities below the minimum step of unloading to as low as 5 percent capacity (depending on both the unit and operating conditions) by introducing an artificial load. Hot gas bypass shall be installed on only one refrigerant circuit (first stage of cooling).CURBGeneral Requirements:Rooftop manufacturer shall supply a prefabricated 12 gauge galvanized steel, mounting curb, designed and manufactured by the unit manufacturer, shall be provided for field assembly on the roof decking prior to unit shipment.24-inch high roof curb shall be a full perimeter type with complete perimeter support of the air handling unit. The curb shall be a minimum of 24 inches high with liquid tight, continuously welded corner seams, prime coat, 2-inch by 4-inch wood nailing strip and 3-pound density rigid fiberglass insulation. Curb shall be straight cantless type with full metal liner. Gasket shall be provided for field mounting between the unit base and roof curb.Unit shall include an insulated panel under compressor section to prevent condensation forming on bottom. Provide dimensions to allow for easy duct location and connection to roof curb prior to unit placement. Curb design shall meet requirements of National Roofing Contractors Association and shall account for the slope of the roof to insure the rooftop unit is level. - EXECUTIONAUTOMATIC SHUTDOWN OF EQUIPMENTSmoke Detectors:*****Note to Specifier: Edit and coordinate with Electrical Department the locations for smoke detectors. Usually smoke detectors must be located inside the building not exposed to outside air conditions on ductwork located above the roof.*****Contractor shall coordinate and assist in the installation in each rooftop air handling unit handling over 2,000 cfm, a smoke detector in return air main duct adjacent to unit, and a smoke detector in main discharge of unit. Provide duct access panels to smoke detector units.Contractor, under Division 26, shall furnish, install, and wire smoke detector to alarm central panel and shutdown fan motor. Temperature Control Contractor shall close smoke dampers at rooftop air handling unit on fan shutdown.EXAMINATIONGeneral Requirements:Examine areas and conditions, with installer present, for compliance with requirements for installation tolerances, housekeeping pads, and other conditions affecting performance of air handling units.Coordinate housekeeping base location with concrete installer.Examine rough-in for steam, hydronic, condensate drainage piping, and electrical to verify actual locations of connections prior to installation.Do not proceed until unsatisfactory conditions have been corrected.EQUIPMENT INSTALLATION AND SUPPORT*****Note to Specifier: Design professional to provide service platform or other means to access on the exterior.*****Framework: Furnish and install angle and channel iron and welded structural steel supports incidental to mounting units as shown on Drawings. Coat steel work provided under this Section with rust inhibitive primer.Vibration Isolation: Units shall have vibration isolators specified in unit description. Refer to Section 23 05 48. Bolt floor mounted isolators to unit and to floor.For units installed on roof, contractor shall install a 5/16-inch thick neoprene waffle pad, Type G isolator, continuous, between unit and top of curb. Refer to Section 23 05 48.Flexible Connections: Flexible connections to ductwork and units shall be ventglas double, neoprene coated fabric, 1/16 inch thick or equal and approved. Provide instrument test holes and caps located downstream of discharge of each fan for checking and adjusting air flow. Balance fans as specified.Installation: Install air handling units level and plumb, in accordance with manufacturer's written instructions. Arrange installation of units to provide access space around air handling units for service and maintenance. Install unit in location indicated on Drawings. Bolt sections together with gaskets installed in accordance with manufacturer's recommendations. Connect ductwork to unit with flexible connections, unless specified or detailed as a direct connection.Connections to coils shall be made under Sections 23 22 13.23, Aboveground Hydronic Piping, 23 22 13.23, Aboveground Steam and Condensate Heating Piping, 23 23 00, Refrigerant Piping.Contractor shall provide steam, glycol-hot, and glycol-chilled water, and/or refrigerant piping connections to coils as designed on Drawings.Connections on supply side shall include gate valve, union, and supply union connection.Connections on return side shall include return union connections, balancing fitting, and balancing ball valve.Connections to refrigerant coils shall be as detailed on Drawings.Where 3-way control valves are called for on Drawings, a balancing fitting and a balancing ball valve shall be included in the bypass leg.Lubrication: After systems and equipment have been installed and just prior to building acceptance, properly lubricate motors and equipment installed under this Section.Balancing: Adjust fan speed to provide specified output, adjust flow through coils to specified flow, and prepare report as specified in Section 23 05 93, Testing, Adjusting, and Balancing for HVAC.Provide instrument test holes and caps located downstream of discharge of each fan for checking and adjusting air flow. Balance fans as specified in Section 23 05 93, Testing, Adjusting, and Balancing for HVAC.Operate fans with VFDs through all operating speeds, note rough operation speeds, adjust VFDs to avoid operation in speeds which cause (resonance) vibration.Condensate Drain: Provide required trap height for condensate to flow. Coordinate outlet location with floor drain locations. This Contractor shall pay for non-coordinated piping changes.Roof Curbs: Roof curb is furnished by this Contractor and installed by this Contractor.SOUND DATAGeneral Requirements: Sound data for each fan shall not exceed listed ratings as scheduled. Ratings are at the outlets of supply plenums or sound attenuators. If site condition sound data is found to exceed values listed, the Contractor shall make corrections required and pay for all sound testing.ENVIRONMENTGeneral Requirements: Contractor shall be responsible to maintain equipment and components in a dry and clean condition during storage and installation. Damage caused by dirt, mold and rust shall be repaired or replaced to the Owners (representatives) satisfaction.CENTRAL-PACKAGED, OUTDOOR, CENTRAL-STATION AIR-HANDLING UNIT SCHEDULERefer to Drawings for schedules.END OF SECTION 23 75 13 ................
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