Section 15733 - Heating and Ventilating Units

DaimlerChrysler Construction Standards 12/17/04

SECTION 15733 - HEATING AND VENTILATING UNITS

PART 1 - GENERAL

0.1 SUMMARY

A. Section includes rooftop heating and ventilating units. This HVAC equipment serves the substation rooms.

B. Related Sections include the following: 1. Division 15 Section “Motors” for general requirements of factory-installed motors

0.2 SUBMITTALS

A. Product Data: Include manufacturer's technical data for each model indicated, including rated capacities of selected model clearly indicated; dimensions; required clearances; shipping, installed, and operating weights; furnished specialties; accessories; and installation and startup instructions.

B. Shop Drawings: Detail equipment assemblies and indicate dimensions, weights, loadings, required clearances, method of field assembly, components, and location and size of each field connection. Detail mounting, securing, and flashing of roof curb to roof structure. Indicate coordinating requirements with roof membrane system. 1. Wiring Diagrams: Detail wiring for power, signal, and control systems and differentiate between manufacturer-installed and field-installed wiring.

C. Commissioning Reports: Indicate results of startup and testing commissioning requirements. Submit copies of checklists.

D. Maintenance Data: For equipment to include in maintenance manuals specified in Division 1.

E. Warranties: Special warranties specified in this Section.

0.3 QUALITY ASSURANCE

A. Single-Source Responsibility: Rooftop air-handling unit, 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.

B. DaimlerChrysler Corporate Standards: Manufactured unit shall conform to the attached DaimlerChrysler noise specification. Manufacturer will review DaimlerChrysler Corporation Occupational Safety and Health Manuals, Volumes 1 and 2 to assure the contract work complies with these standards. The DaimlerChrysler Project Engineer will make these manuals available to the Contractor on request.

C. Regulatory Agencies, Codes and Standards: Provisions of referenced Specifications and Standards, as applicable, govern quality of materials and workmanship required under the Contract. Units shall bear UL and ETL approval labels covering the entire unit (not just components). 1. Testing and rating of fans shall be in accordance with AMCA standards. Tests shall be conducted in a certified AMCA laboratory. 2. All components shall be listed by UL and have UL label. 3. Rooftop units shall be designed, manufactured, and tested in accordance with UL requirements.

HEATING AND VENTILATING UNITS 15733 - 1 of 8 DaimlerChrysler Construction Standards 12/17/04

4. Unit shall bear ETL label as a unit.

D. Testing: Manufactured unit and its components shall be tested per the following: 1. National Fire Protection Association (NFPA) 255 – Test of Surface Burning Characteristics of Building Materials 2. Testing and rating of fans shall be in accordance with AMCA standards. Tests shall be conducted in a certified AMCA laboratory. 3. Electrical components shall be listed by UL and have UL and ETL Semko labels. 4. Rooftop units shall be designed, manufactured, and tested in accordance with UL requirements.

E. Start-Up: Separate start-up and on-site performance testing will occur during summer ventilation, and winter heating ambient conditions.

0.4 DELIVERY, STORAGE, AND HANDLING

A. Deliver rooftop units as factory-assembled units with protective crating and covering.

B. Coordinate delivery of units in sufficient time to allow movement into building.

C. Handle rooftop units to comply with manufacturer's written rigging and installation instructions for unloading and moving to final location.

D. Warehousing: Owner's intent is to store units on site for minimum time required to stage lifts. Warehousing costs if required to meet delivery schedule are to be included in this contract.

0.5 COORDINATION

A. Coordinate installation of roof curbs, equipment supports, and roof penetrations with roof construction. Roof specialties are specified in Division 7 Sections.

0.6 WARRANTY

A. Provide standard manufacturers warranty for units. Also conform to Division 1 warranty requirements.

B. Special Warranty: A written warranty, executed by the manufacturer and signed by the Contractor, agreeing to replace components that fail in materials or workmanship, within the specified warranty period, provided manufacturer's written instructions for installation, operation, and maintenance have been followed.

0.7 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. 1. Fan Belts: One set for each belt-drive fan. 2. Filters: One set of filters for each unit.

PART 2 - PRODUCTS

0.1 MANUFACTURERS

A. Manufacturers: Unless otherwise directed by the Owner, provide products by one of the following: 1. Carrier Corp.; Carrier Air Conditioning Div. 2. Energy Labs 3. Greenheck.

4. Mammoth. 5. McQuay International. 6. Temtrol, Inc. 7. TMI 8. Trane Company (The); North American Commercial Group. 9. Webco. 10. York International Corp.

0.2 MANUFACTURED UNIT HOUSING

A. Description: Factory assembled and tested; designed for roof installation; and consisting of heaters (where scheduled), fans, wiring, temperature controls, filters, and dampers.

B. 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, including necessary spreader bar assemblies, shall be attached to the unit. Protruding lugs shall be removable, bolt on type. Lug location shall be conducive to fast installation.

C. Double-Wall Casing: Base to include manufacturer's standard primed and painted exterior coating system. Air-dry coating durable to withstand 670 consecutive hours of salt spray application in accordance with ASTM B 117, with color is to match building siding (see paragraph 2.2K). Alternate bid to be galvanized steel sheets, phosphatized, and unfinished. Structural members shall be galvanized steel with access door frames constructed of minimum 18 gage galvanized steel. Unit enclosure shall be solid double-wall construction with 1 inch thick, 1-1/2 lb density coated fiberglass insulation sandwiched between 16 gage outer skin and 20 gage inner liner. Roof shall have 16 gage outer panel and 20 gage inner liner. Floor shall be fully welded 14 gage with 16 gage liner over insulation. Entire unit shall have a structural steel frame with structural members at shipping splits, suitable to draw together, gasket, and bolt up, with no gaps or potential leak points.

D. Insulation: Unit insulation shall meet NFPA 90A flame and smoke ratings. Coatings and adhesives used in 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.

E. Access Doors: Double–wall insulated gasketed type to provide access to each section of the unit. Doors shall have stainless steel piano hinges. 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. Provide minimum two latches per 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 wind from slamming the door closed. Access doors to have a step up from roof deck, cantilevered from the base frame.

F. Outside air inlet configuration shall be blowing rain/snow designed, hooded rear wall inlet.

G. Painting: AHU 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. 1. Color: Provide color similar to building siding, as selected from manufacturer's standard color offerings as approved by the Architect/Engineer.

H. Electric Heat: Manufacturer's standard construction, factory wired for single-point wiring connection, with overcurrent and overheat protection devices.

0.3 SUPPLY AIR FANS

A. General: Painted steel, centrifugal, double width, double inlet, belt-driven fans. (Unit supplier shall provide replacement 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 minimum 1 inch x 1 inch opening safety inlet screens. Exposed shafts shall be guarded.

B. Fan Sizing: Fan and drive shall be sized to provide full capacity flow rate with filters installed. Initial sheave selection shall correspond to first stage filters only. Contract to include cost to furnish a second set of sheaves, which will be sized and furnished to meet system balancing contractor's requirements. Sheave requirement applies only to AHUs without electric heat.

C. Fan/Drive Mounting: Isolate fan/motor assembly from unit with 2 inch, factory set, spring vibration isolators. Provide thrust restraint isolation on the fan housing/fan board to assure smooth fan start-up and operation. Provide temporary restraints to prevent fan/drive movement during shipment of unit.

D. Fan Motor/Drive: 1800 RPM, ODP, premium efficiency, T-frame motor, electrically protected by dual element fuses in each leg and with motor overload protections in each leg. Motors shall be US Motors, Reliance, Siemens or Baldor. Motors shall be located for easy access and removal. Belt drives shall be selected for 150 percent service factor. Minimum of two belts shall be provided. Provide OSHA approved belt and shaft guards, with tachometer openings, and painted safety yellow.

0.4 DAMPERS

A. General: Provide opposed blade two position outside air dampers and electric control system. Damper blades shall be minimum 16 gage, galvanized steel with 3/4-inch jack shafts. Damper performance shall be AMCA certified. Bearings shall be machined bronze material.

B. Drives: Drives shall be selected to provide a minimum of 150 percent of the required torque for the application.

C. Outside air intake hood shall be blown snow and blown rain proof, with bird screen.

0.5 FILTER SECTION

A. Framing: Filter section to be suitable for first stage 2-inch thick, 24-inch by 24-inch pleated panel type filters and second stage 12-inch deep rigid filter bank for units without electric heat. Holding frames shall be factory fabricated of 16 gage, galvanized steel. A polypropylene fin seal on the main filter track shall eliminate filter bypass air (less than one half of 1 percent housing to ambient leakage). There shall be a poly sponge door seal gasket to assure proper door-to-filter seal. Mount panel filter media in supporting frames and coordinate supports to retain elements to provide a substantial, leakproof installation. Required filter framing, hardware, and accessories shall be provided. Units with electric heat shall have the same filter requirements as above, except they do not have final filters (second stage), and the filter is 4 inches thick. See drawing schedule for filter efficiency rating. Final filters for the main ventilation units (AHU-64 and AHU-65) shall be equal to Camfil Farr Durafil with a Merv 13 rating per ASHRAE 52-2.

B. Construction and Operation Filters: Filters shall be Merv 13 pleated rigid filters, furnished as a part of this Contract. Each filter shall consist of a fiberglass filter media, support grid, and

enclosing frame. First stage filter shall be listed by Underwriters Laboratories as Class 2. Provide 3 sets of filters for use during construction, and two specified sets of prefilter and one set of final filters for post deep clean and final operation.

0.6 ROOF CURBS

A. General: Provide full perimeter curb designed to accommodate and support the entire custom rooftop air handler with a slope to match roof. Curb shall be factory constructed steel, designed to span purlin to purlin and flat to ensure that the unit is level, compensating for roof pitch. A roof plan will be distributed which will indicate design location and sloping required for the units. Contractor shall be responsible for shimming the curb to maintain flatness. Roof curb shall be 16 inch high minimum at highest point of roof. Curb shall be manufactured according to National Roofing Contractors Association Guidelines. Supply ductwork and electrical service and control wiring connections shall be through the bottom of the unit and inside of the roof curb.

B. Curb Sealing: Provide neoprene gasketing material for sealing between the air-handling unit assembly and the roof curb. Supplier shall provide appropriate flashing around the air handler to assure a watertight enclosure of the equipment and curb. Provide 12 gage sheet metal cant for prevention of water ponding at the unit and for insulation attachment around entire unit curb.

0.7 ELECTRICAL

A. Electrical panels shall be constructed to NEC regulations and shall be UL listed. Provide laminated wiring diagrams showing wiring; to be installed in a drawing holder on the inside cover of each panel. 1. Components shall be individually labeled and individually wired to a divided and numbered terminal strip. Wiring in the panel shall be in wireway. Wiring shall be color coded and number tagged to match the control diagram supplied with the unit. 2. Control wiring conductors shall be No. 14 AWG, 19 strand copper, 600 volt, thermoplastic insulated, water and oil resistant, 90 deg C machine tool wire. 3. Wire and cable for power wiring shall be single conductor, No. 12 AWG or larger as required, stranded copper rated 600 volts.

B. Convenience Outlet: Electrical compartment shall have a 115 VAC GF duplex convenience outlet and 1.5 kVA, 480-120V step-down transformer wired ahead of the main unit disconnect and separately fused and a toggled disconnect for unit service.

C. Lighting: Each section in the AHU shall be provided with an incandescent light and marine type lens and guard. Bulbs shall be 100 W Tuff Duty and shall be shipped loose with the lenses and guards for installation by the field contractor. A light shall be provided on both sides of the supply fan.

D. Motor Control: Provide phase loss/imbalance monitoring on drive motors to alarm/trip upon detection of improper voltage supply.

E. Construction: Vertically mounted fuses, disconnect switches, circuit breakers shall have line side wired to top of device. Panel wiring shall be completely labeled using wire markers and terminal black connector tags.

0.8 MOTORS

A. Refer to Division 15 Section "Motors" for general requirements of factory-installed motors.

B. Motor Construction: NEMA MG 1, general purpose, continuous duty, Design B, premium efficiency.

C. Enclosure Type: Open, dripproof, T-frame mounting.

0.9 SOURCE QUALITY CONTROL

A. Sound Power Level Ratings: Comply with ARI 270, "Standard for Sound Rating of Outdoor Unitary Equipment."

0.10 AUTOMATED CONTROLS

A. On a call for ventilation from wall-mounted thermostat for main substation AHU the associated dampers shall be commanded open and main AHU turned on. (AHU-64 and AHU-65). Large unit will maintain room temperature of 104 deg F maximum. Main AHU shall run for minimum of 5 minutes (adjustable) via timer. Main AHU shall be commanded off upon space temperature lowered to 85 deg F (adjustable).

B. Outdoor air dampers for air handlers shall be open when unit fan is on and shall be closed when fan is off. Control wiring is by the Mechanical trades.

C. Provide two sets of normally open and closed sets of contacts for tie-in to area smoke detection system. Upon system detection of smoke, AHU fan shall deenergize per applicable Mechanical Code and an alarm shall be sent to the fire alarm panel.

D. Wire the associated relief hood dampers to open when AHU-64 and AHU-65 fans turn on, and close when fans turn off.

E. Coordinate controls installation with other trades.

PART 3 - EXECUTION

0.1 PRE-SHIPMENT REQUIREMENTS

A. General: Each air handler shall be assembled in the shop, wired, and operational performance proven prior to shipment. Manufacturer's quality of assurance certificate, indicating the date and results of shop performance tests, shall be included with each unit. Notify Owner and Engineer a minimum of two weeks prior to Operational Performance Testing, to allow witnessing.

B. Lockout Placards: Provide lockout placards supplied by a DaimlerChrysler approved vendor. Comply with DaimlerChrysler Safety Bulletin No. S-43 - Lockout/Energy Control Procedure.

0.2 POST SHIPMENT REQUIREMENTS

A. Start-Up Services: Provide the services of a factory-authorized service representative to start up units in accordance with manufacturer's written start-up instructions. Test controls and demonstrate compliance with requirements. Replace defective controls and equipment as required. Owner may elect to witness these tests. Provide a checklist/buyoff form for each unit which shall be signed by the unit manufacturer and Owner prior to the installing contractor leaving the site.

B. Service representative to verify that actual External Static Pressure (ESP) has been placed on AHU and that the fan will operate in a safe flow condition in an acceptable range on the fan curve; or direct the resheave/balancing effort to reduce fan speed and flow associated with little or no ESP.

0.3 EXAMINATION

A. Examine roof for compliance with requirements for conditions affecting installation and performance of rooftop units. Do not proceed with installation until unsatisfactory conditions have been corrected.

0.4 INSTALLATION

A. Install units according to manufacturer's written instructions.

B. Install units level and plumb, maintaining manufacturer's recommended clearances.

C. Curb Support: Install roof curb on roof structure, level, according to NRCA's written installation instructions. Install and secure rooftop units on curbs and coordinate roof penetrations and flashing with roof construction.

D. Unit Support: Install unit on structural curbs and level.

0.5 CONNECTIONS

A. Duct installation requirements are specified in other Division 15 Sections. Drawings indicate the general arrangement of ducts. The following are specific connection requirements: 1. Install ducts to termination in roof mounting frames. Where indicated, terminate duct through roof structure and insulate space between roof and bottom of unit.

B. Electrical: Conform to applicable requirements in Division 16 Sections.

C. Ground equipment. 1. Tighten electrical connectors and terminals according to manufacturer's published torque- tightening values. Where manufacturer's torque values are not indicated, use those specified in UL 486A and UL 486B.

0.6 COMMISSIONING

A. Verify that installation is as indicated and specified.

B. Complete manufacturer's installation and startup checks and perform the following: 1. Level unit on curb and flash curb to unit and to roof. 2. Inspect for visible damage to unit casing. 3. Verify that clearances have been provided for servicing. 4. Check that labels are clearly visible. 5. Verify that controls are connected and operable. 6. Remove shipping bolts, blocks, and tie-down straps. 7. Verify that filters are installed. 8. Adjust vibration isolators. 9. Check acoustic insulation. 10. Check operation of dampers.

C. Lubricate bearings on fan.

D. Check fan-wheel rotation for correct direction without vibration and binding.

E. Adjust fan belts to proper alignment and tension.

F. Start unit according to manufacturer's written instructions. 1. Complete startup sheets and attach copy with Contractor's startup report.

G. Check and record performance of interlocks and protection devices; verify sequences.

H. Operate unit for an initial period as recommended or required by manufacturer.

I. Calibrate thermostats.

J. Check internal isolators.

K. Check dampers for proper operation.

L. Check controls for correct sequencing of fan start, dampers, and normal shutdown.

M. Measure and record the following minimum and maximum airflows. Plot fan volumes on fan curve. 1. Supply-air volume.

N. After starting and performance testing, change filters, lubricate bearings, adjust belt tension, and check operation.

0.7 DEMONSTRATION

A. Review data in the maintenance manuals.

END OF SECTION

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