Packaged, Outdoor, Central Station Air Handling Units ME- Building Group

SECTION 237413 – PACKAGED, OUTDOOR, CENTRAL-STATION AIR-HANDLING UNITS

PART 1 - GENERAL

1.1  RELATED DOCUMENTS

  1. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division01 Specification Sections, apply to this Section.

1.2  SUMMARY

  1. This Section includes packaged, factory-assembled, rooftop heating and cooling units consisting of structural frame, casing, fans, coils, filters, dampers, controls, piping, wiring, with components, material, accessories services, and testing necessary for a complete and fully functional system.
  2. Units shall be provided with separately shipped roof curb.
  3. Basis of Design: R-134a DX cooling unit.

1.3  SUBMITTALS

  1. With the Bid, submit the following:
  2. Basic drawing of unit showing configuration, dimensions, shipping splits, split weights, location and size of natural gas, power, and drain connections. Include location and size of de-ionized water or steam piping connections for humidification alternates.
  3. Product data with rated capacities of overall unit and major components of the refrigerant system, the heating system, and the humidifying system alternates.
  4. A list of components or sub-assemblies requiring installation by the field contractor.
  5. Fan performance curves, burner NOX and CO performance curves and sound compliance data.
  6. Preliminary sound power data at 32, 63, 125, 250, 500, 1000, 2000, 4000, and 8000 Hz and sound pressure data. Sound pressure data shall be established as a distance of 10 feet from the operating unit.
  7. Clearly specifiy additional installation requirements by others such as heat trace, drains, traps, etc. , that are necessary for the regular unit operations during ALL seasons.
  8. Submittal Schedule: Within 1 week of the bid award, provide a submittal schedule including a table of recipients (with quantities) to be provided by Owner upon award.
  9. LEED Submittals:
  10. Product Data for CreditEA4: Documentation indicating that equipment and refrigerants comply.
  11. Product Data for PrerequisiteIEQ1: Documentation indicating that units comply with ASHRAE62.1, Section5 - "Systems and Equipment."
  12. Shop Drawings: Indicate dimensions, weight loadings, weight distribution, and clearances required around and between construction elements. Include drawings detailing roof curb assembly, mounting, securing, and flashing to the roof structure. Include gas train configuration and components including regulator.
  13. Wiring Diagrams: For power supply wiring and ladder-type wiring diagrams of interlock and control wiring. Clearly differentiate between factory-installed and field-installed wiring. Include manufacturer's sequence of operation.
  14. Controls: Control and instrument data sheets, sequence of operation, system architecture including interface to existing system, air handling unit schematic locating control devices and showing terminations to the DDC controller. Include electronic copies of AHU control programming including a licensed copy of the programming software.
  15. Certificates: Certified performance data indicating entering and leaving air conditions. Include IRI and TSSA (in Canada) gas train certification and warranty certificates.
  16. Weights and Scale Certificates: Shall be submitted to the Owner prior to shipment.
  17. Operating and Maintenance Data: Prior to substantial completion of the project, submit complete copies of maintenance data and parts list, including operating and servicing procedures, preventative maintenance schedule and "troubleshooting" maintenance guide. Include certified as-built drawings of units.
  18. Additional requirements: Verify with the architect for the condition of the roof with respect to roof slopes, unit locations, etc. before commencing with the fabrication.
  19. Acessories: Drain traps (positive or negative, depending upon the project) will need to be provided by the Manufacturer, or clearly defined in the shop drawing that it will need to be provided by the Mechanical installer.

1.4  QUALITY ASSURANCE

  1. Single-Source Responsibility: Rooftop air-conditioner, heating section, components, temperature controls, and accessories shall be from a single source. Furnish the name, address, and telephone number of the nearest field service organization with responsibility and accountability to answer and resolve problems regarding compatibility, installation, performance, and acceptance of units.
  2. Chrysler Standards: The manufactured unit shall conform to the attached Chrysler noise specification. Manufacturer will review Chrysler Occupational Safety and Health Manuals, Volumes 1 and 2 to assure the contract work complies with these standards. .
  3. ARI Compliance:
  4. Comply with ARI203/110 and ARI303/110 for testing and rating energy efficiencies for RTUs.
  5. Comply with ARI270 for testing and rating sound performance for RTUs.
  6. ASHRAE Compliance:
  7. Comply with ASHRAE15 for refrigeration system safety.
  8. Comply with ASHRAE33 for methods of testing cooling and heating coils.

LEEDPrerequisiteIEQ1 requires compliance with requirements in ASHRAE62.1, including requirements for controls, surfaces in contact with the airstream, particulate and gaseous filtration, humidification and dehumidification, drain pan construction and connection, finned-tube coil selection and cleaning, and equipment access. Verify, with manufacturers, availability of units with components and features that comply with these requirements.

  1. Comply with applicable requirements in ASHRAE62.1, Section5 - "Systems and Equipment" and Section7 - "Construction and Startup."

LEEDPrerequisiteEA2 requires minimum efficiency equal to requirements in ASHRAE/IESNA90.1.

  1. ASHRAE/IESNA90.1 Compliance: Applicable requirements in ASHRAE/IESNA90.1, Section6 - "Heating, Ventilating, and Air-Conditioning."
  2. Regulatory Agencies, Codes and Standards: The provisions of the referenced Specifications and Standards, as applicable, govern the quality of materials and workmanship required under the Contract. Units shall bear CGA or ETL and CSA or ESA and TSSA in Canada, approval labels covering the entire unit, not just components.
  3. Piping and Tubing: Perform welding, brazing, soldering and cutting work in conformance with requirements of Contract Documents and applicable provisions of the following:
  4. ANSI B31.1. Power Piping with Current Addenda
  5. ASME, Boiler and Pressure Vessel Code.
  6. Materials: Units shall be manufactured with materials meeting the following standards:
  7. ASTM – American Society for Testing and Materials A653/A653M, Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process
  8. ASTM – American Society for Testing and Materials, E84 – Test Method for Surface Burning Characteristics of Building Materials
  9. Testing: The manufactured unit and its components shall be tested per the following:
  10. NFPA 255 – Test of Surface Burning Characteristics of Building Materials
  11. Testing and rating of fans shall be in accordance with AMCA standards. Tests shall be conducted in a certified AMCA laboratory.
  12. Refrigeration coils shall be selected, constructed, and tested in accordance with ARI Standard 410.
  13. Refrigerating system construction shall be in accordance with ASHRAE 15 "Safety Code of Mechanical Refrigeration".
  14. Energy Efficiency Ratio (EER) of rooftop units shall be equal to or greater than prescribed by ASHRAE 90A "Energy Conservation in New Building Design".
  15. Electrical components shall be listed by ULC and ESA, and have ULC and CSA labels, in Canada.
  16. Rooftop units shall be designed, manufactured, and tested in accordance with UL requirements.

1.5  DELIVERY, STORAGE AND HANDLING

  1. General: Units shall be delivered to and received by the Owner assigned installer. Equipment shall be completely shop assembled as much as possible. Provide a list detailing components or subassemblies to be shipped separately.
  2. Unit Sections: Equipment too large for completely assembled shipment shall be shipped in as few sections as possible. Each section shipped shall be complete with interconnecting wiring, piping, and accessories required for final installation. Field assemblies required shall be only reconnecting piping, wiring, and casing. Open ends of sectional-piece units shall be provided with secure airtight and watertight closures during shipment.
  3. Warehousing: The Owners intent is to store units on site for the minimum time required to stage the helicopter lifts. Warehousing costs if required to meet the delivery schedule are to be included in this contract.

1.6  Scheduling and sequencing

  1. Following selection of the installer, manufacturer shall meet with the Owner and Contractor to develop approved shipping sequence. Provide notification to Owner and Contractor one week in advance of each shipping date.

1.7  SPECIAL WARRANTY

  1. Parts, Refrigerant, and Labor: Provide written warranty, agreeing to replace/repair, within warranty period, parts and refrigerant having inadequate and defective materials and workmanship, including leakage, breakage, improper assembly, or failure to perform as required; provided manufacturer’s instructions for handling, installing, protecting, and maintaining units have been adhered to during warranty period. Warranty costs shall include the removal and reinstallation of associated equipment and materials as required to perform repairs.
  2. Warranty Period: The warranty period shall be valid from the date of functional buyoff of the installed units by the manufacturer and the Owner.

1.8  MAINTENANCE MATERIAL SUBMITTALS

  1. Furnish extra materials described below that match products installed and that are packaged with protective covering for storage and identified with labels describing contents.
  2. Fan Belts: One set for each belt-driven fan.
  3. Filters: One set of filters for each unit.

PART 2 - PRODUCTS

2.1  GENERAL

  1. Unit Performance Requirements: The manufacturer is responsible for sizing equipment to meet summer and winter leaving conditions as scheduled on the Drawings. Heating and cooling loads are to be verified by the manufacturer.
  2. Silicone: Air handler components shall be silicone free, including lubricants, sealant, packings, coating, and gaskets.
  3. Noise: Air handling unit, including compressors and condensers, shall not exceed a noise level of 80 dBA at 3 feet from the source
  4. Service Connections: Piping and wiring shall be brought to the air handler through the curb, by the installer.

2.2  MANUFACTURED UNIT HOUSING

  1. General: Unit shall be factory assembled designed for rooftop installation, and consist of compressors, condensers, evaporator coils, condenser fans, refrigeration with temperature controls, economizer, filters, and dampers. Unit shall be provided with initial charge of refrigerant.

LEEDPrerequisiteIEQ1 requires compliance with ASHRAE62.1, in which Section5.14 - "Access for Inspection, Cleaning, and Maintenance" sets requirements for equipment access. If applying for LEED certification, comply with requirements in ASHRAE62.1.

  1. General Fabrication Requirements for Casings: Formed and reinforced double-wall insulated panels, fabricated to allow removal for access to internal parts and components, with joints between sections sealed.
  2. Structure: Unit shall have integral structure mounted on a continuous structural galvanized steel base such as 8 inch channels or I-beams to support a single lift onto roof curb. Unit base shall be equipped with a curb angle. Air handler support shall be extended to support the separate condenser on the curb. Air handler section shall be a one-piece construction if possible.
  3. Weight: Sections of the air handler shall satisfy the size and weight requirements for helicopter lifts. (Size and weight limitations are inversely proportional due to downdraft and vary between 440 sq ft of horizontal surface area at 18,000 pounds to 250 sq ft of horizontal surface area at 21,000 pounds.) Manufacturer shall design the unit splits such that the number of helicopter lifts are kept to a minimum. Lifting lugs shall be provided, a minimum of 4 lugs per section to ensure proper rigging. Rigging and lifting safety instructions shall be attached to the unit.
  4. Double-Wall Casing: Steel sheets, phosphatized, and finished with air-dry coating durable to withstand 670 consecutive hours of salt spray application in accordance with ASTM B117. Color is to match building siding. Structural members shall be minimum 14 gauge galvanized steel with access door frames constructed of minimum 18 gauge galvanized steel. Unit enclosure shall be solid double-wall construction with 2 inch thick, 1-1/2 lb density coated fiberglass insulation sandwiched between 18 gauge outer skin and 20 gauge inner liner. Casing walls shall have 18 gage outer panel and 20 gauge inner liner. Roof shall have 18 gage outer panel and 20 gage inner liner. Floor shall be fully welded 14 gage with 20 gage liner over insulation.
  5. Drainage: The unit floor shall be fully welded galvanized steel with watertight weld wall seams 4 inches high, complying with ASHRAE 62.1, and capable of containing ponding water. Roof and wall seams shall be joined with continuous, silicone-free sealant. Fan and coil section deck shall be sloped to a trapped unit sump. Coils shall have drain pans piped to the sump. Supply fan floor section shall have single piece floor plate. Drain pans shall be suitable for field welding. Drains requiring drain traps shall be located such that the traps can be field installed under the unit and discharged through the unit base steel. Unit base steel shall include circular openings required for drain piping insertion. Galvanized piping for traps and drains, including anti-sweat insulation, shall be installed with the unit. If shipping restrictions prevent shop installation, the piping and insulation shall be shipped loose for field installation.
  6. Insulation: Unit insulation, whether directly in air stream or not (i.e., under base, sandwiched between double-wall panels, or mastic coating on either side of base), shall meet NFPA 90 A flame and smoke ratings. Coatings and adhesives used in the construction of packaged rooftop air-conditioners shall meet a flame spread rating not over 25 and a smoke developed rating no higher than 50 as required in NFPA 90A.
  7. Access Doors: Double–wall insulated gasketed type to provide access to each section of the unit. Doors shall have stainless steel piano hinges and latches. Door hinges and latches shall be positive action type and shall be easily adjustable to allow for a tight seal between the door and the unit. Door latches shall have handles on both sides of the door. Doors shall be a minimum of 2 feet wide by 6 feet high. Access doors shall open against unit operating pressure. Provide stainless steel hold open device that attaches the door to the casing in the 180 degree open position, to prevent the wind from slamming the door closed.
  8. Compartments: The gas train, control and burner exhaust fan cabinets shall be reach in type, attached to the air handling casing. Panels shall have gasketed doors; conduit and pipe panel penetration shall be sealed to prevent corrosion.
  9. Provide non-conductive grating to raise the reach-in compartments up to the level of door threshold.
  10. Finish: AHU and condenser shall be furnished with baked-on enamel prime and finish paint. Color shall match building siding . Metal siding that matches the building siding may be provided (as an alternate to painting) for the AHU. AHU manufacturer shall coordinate siding order with siding supplier. Equipment tags with AHU number and pertinent nameplate information shall be attached to the outside of each unit.

Paragraph below may be required to comply with Project requirements or authorities having jurisdiction. Retain paragraph to comply with LEEDPrerequisiteIEQ1.

  1. Airstream Surfaces: Surfaces in contact with the airstream shall comply with requirements in ASHRAE62.1.

2.3  SUPPLY AIR FANS

  1. General: Painted steel, centrifugal, double width, double inlet, belt-driven fans. (Unit supplier shall provide and replace sheaves as required to meet design conditions after testing and balancing air flows is done by others.) Motor and fan bearings shall be ball bearing type with 200,000 hours minimum L-10 life with grease lines extended outside the housing. Provide flexible connection between fan outlet and unit discharge outlet. Fan inlets shall be equipped with inlet screens.

LEEDPrerequisiteEA2 requires compliance with ASHRAE/IESNA90.1. ASHRAE/IESNA90.1, Section6.5.3 - "Air System Design and Control," sets requirements for fans and fan controls. If applying for LEED certification, comply with requirements in ASHRAE/IESNA90.1.