bafbrwhq15732.pdf

SECTION 15732 REPAIR WING HEADQUARTERS, BLDG 706

PACKAGED OUTDOOR, CENTRAL-STATION AIR HANDLING UNITS CRWU 06-2071

06/09/09 15732-1 BUCKLEY AFB

SECTION 15732 - PACKAGED, OUTDOOR, CENTRAL-STATION AIR-HANDLING UNITS

PART 1 - GENERAL

1.01 SUMMARY:

A. This Section includes packaged, outdoor, central-station air-handling units (rooftop units) with the following components and accessories:

1. Direct-expansion cooling.

2. Economizer outdoor- and return-air damper section.

3. Integral, space temperature controls.

1.02 REFERENCES:

A. Applicable Standards:

1. Air-Conditioning & Refrigeration Institute (ARI):

a. 210/240 - Unitary Air-Conditioning and Air-Source Heat Pump Equipment.

b. 270 - Sound Rating of Outdoor Unitary Equipment.

c. 340/360 - Commercial and Industrial Unitary Air-Conditioning and Heat Pump

Equipment.

d. Guideline B - Roof Mounted Outdoor Air-Conditioning Installations.

2. American National Standards Institute (ANSI):

a. Z21.47 - Gas-Fired Central Furnaces.

3. American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE):

a. 15 - Safety Standard for Refrigeration Systems.

b. 33 - Methods of Testing Forced Circulation Air Cooling and Heating Coils (ANSI).

c. 52.1 - Gravimetric and Dust-Spot Procedures for Testing Air-Cleaning Devices

Used in General Ventilation for Removing Particulate Matter (ANSI).

d. 52.2 - Method of Testing General Ventilation Air-Cleaning Devices for Removal

Efficiency by Particle Size (ANSI).

e. 62 - Ventilation for Acceptable Indoor Air Quality (ANSI).

4. American Society of Heating, Refrigerating and Air-Conditioning Engineers/Illuminating Engineering Society of North America (ASHRAE/IESNA):

a. 90.1 - Energy Standard for Buildings Except Low-Rise Residential Buildings.

5. ASTM International (ASTM):

a. C916 - Adhesives for Duct Thermal Insulation.

b. C1071 - Fibrous Glass Duct Lining Insulation (Thermal and Sound Absorbing

Material).

6. National Roofing Contractors Association (NRCA):

a. Low-Slope Membrane roofing construction Details Manual. Vol. 1.

7. National Fire Protection Association (NFPA):

a. 54 - National Fuel Gas Code (ANSI).

b. 70 - National Electrical Code.

c. 90A - Installation of Air Conditioning and Ventilating Systems (ANSI).

d. 90B - Installation of Warm Air Heating and Air Conditioning Systems (ANSI).

8. Structural Engineering Institute/American Society of Civil Engineers (SEI/ASCE):

a. 7 - Minimum Design Loads for Buildings and Other Structures.

9. Underwriters Laboratories Inc. (UL):

a. 1995 - Heating and Cooling Equipment.

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1.03 DEFINITIONS:

A. DDC: Direct-digital controls.

B. Outdoor-Air Refrigerant Coil: Refrigerant coil in the outdoor-air stream to reject heat during cooling operations and to absorb heat during heating operations. "Outdoor air" is defined as the air outside the building or taken from outdoors and not previously circulated through the system.

C. Outdoor-Air Refrigerant-Coil Fan: The outdoor-air refrigerant-coil fan in RTUs. "Outdoor air" is defined as the air outside the building or taken from outdoors and not previously circulated through the system.

D. RTU: Rooftop unit. As used in this Section, this abbreviation means packaged, outdoor, central-station air-handling units. This abbreviation is used regardless of whether the unit is mounted on the roof or on a concrete base on ground.

E. Supply-Air Fan: The fan providing supply air to conditioned space. "Supply air" is defined as the air entering a space from air-conditioning, heating, or ventilating apparatus.

F. Supply-Air Refrigerant Coil: Refrigerant coil in the supply-air stream to absorb heat (provide cooling) during cooling operations and to reject heat (provide heating) during heating operations. "Supply air" is defined as the air entering a space from air-conditioning, heating, or ventilating apparatus.

1.04 PERFORMANCE REQUIREMENTS:

A. Delegated Design: Design RTU supports to comply with wind and seismic performance requirements, including comprehensive engineering analysis by a qualified professional engineer, using performance requirements and design criteria indicated.

B. Wind-Restraint Performance:

1. Basic Wind Speed: 90 mph (40 m/s)

2. Building Classification Category: II.

3. Minimum 10 lb/sq. ft (48.8 kg/sq. m) multiplied by the maximum area of the mechanical component projected on a vertical plane that is normal to the wind direction, and 45 degrees either side of normal.

C. Seismic Performance: RTUs shall withstand the effects of earthquake motions determined according to SEI/ASCE 7.

1. The term "withstand" means "the unit will remain in place without separation of any parts from the device when subjected to the seismic forces specified."

1.05 SUBMITTALS:

A. General: Submit the following as specified in SECTION 15050 - BASIC MECHANICAL

MATERIALS AND METHODS.

B. Product Data: Include manufacturer's technical data for each RTU, including rated capacities, dimensions, required clearances, characteristics, furnished specialties, and accessories.

C. Field quality-control test reports.

D. Operation and Maintenance Data: For RTUs to include in emergency, operation, and maintenance manuals.

E. Warranty: Special warranty specified in this Section.

1.06 QUALITY ASSURANCE:

A. ARI Compliance:

1. Comply with ARI 210/240 and ARI 340/360 for testing and rating energy efficiencies for RTUs.

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2. Comply with ARI 270 for testing and rating sound performance for RTUs.

B. ASHRAE Compliance:

1. Comply with ASHRAE 15 for refrigeration system safety.

2. Comply with ASHRAE 33 for methods of testing cooling and heating coils.

3. Comply with ASHRAE/IESNA 90.1 for minimum efficiency of heating and cooling.

C. NFPA Compliance: Comply with NFPA 90A and NFPA 90B.

D. Electrical Components, Devices, and Accessories: Listed and labeled as defined in NFPA 70, Article 100, by a testing agency acceptable to authorities having jurisdiction, and marked for intended use.

1.07 WARRANTY:

A. Special Warranty: Manufacturer's standard form in which manufacturer agrees to replace components of RTUs that fails in materials or workmanship within specified warranty period.

1. Warranty Period for Compressors: Manufacturer's standard, but not less than five years from date of Substantial Completion.

2. Warranty Period for Control Boards: Manufacturer's standard, but not less than three years from date of Substantial Completion.

1.08 EXTRA MATERIALS:

A. Furnish extra materials described below that match products installed and that are packaged with protective covering for storage and identified with labels describing contents.

1. Fan Belts: One set for each belt-driven fan.

2. Filters: One set of filters for each unit.

PART 2 - PRODUCTS

2.01 MANUFACTURERS:

A. Basis-of-Design Product: Subject to compliance with requirements, provide a unit from Trane;

American Standard Companies, Inc. or a comparable product by one of the following:

1. AAON, Inc.

2. Addison Products Company.

3. Carrier Corporation.

4. Lennox Industries Inc.

5. McQuay International.

6. YORK International Corporation.

2.02 CASING:

A. 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.

B. Exterior Casing Material: Galvanized steel with factory-painted finish, with pitched roof panels and knockouts with grommet seals for electrical and piping connections and lifting lugs.

1. Exterior Casing Thickness: 0.052 inch (1.3 mm) thick.

C. Inner Casing Fabrication Requirements:

1. Inside Casing: Galvanized steel, 0.034 inch (0.86 mm) thick.

D. Casing Insulation and Adhesive: Comply with NFPA 90A or NFPA 90B.

1. Materials: ASTM C1071, Type I.

2. Thickness: 1/2 inch (13 mm).

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3. Liner materials shall have air-stream surface coated with an erosion- and temperature-resistant coating or faced with a plain or coated fibrous mat or fabric.

4. Liner Adhesive: Comply with ASTM C916, Type I.

E. Condensate Drain Pans: Formed sections of galvanized-steel sheet, a minimum of 2 inches (50

mm) deep, and complying with ASHRAE 62.

1. Double-Wall Construction: Fill space between walls with foam insulation and seal moisture tight.

2. Drain Connections: Threaded nipple.

3. Pan-Top Surface Coating: Corrosion-resistant compound.

2.03 FANS:

A. Belt-Driven Supply-Air Fans: Double width, forward curved, centrifugal; with permanently lubricated, single-speed motor installed on an adjustable fan base resiliently mounted in the casing. Aluminum or painted-steel wheels, and galvanized- or painted-steel fan scrolls.

B. Condenser-Coil Fan: Propeller, mounted on shaft of permanently lubricated motor.

C. Relief-Air Fan: Forward curved or backward inclined, shaft mounted on permanently lubricated motor.

D. Seismic Fabrication Requirements: Fabricate fan section, internal mounting frame and attachment to fans, fan housings, motors, casings, accessories, and other fan section components with reinforcement strong enough to withstand seismic forces defined in SECTION 15071 - MECHANICAL VIBRATION AND SEISMIC CONTROLS when fan-mounted frame and RTU-mounted frame are anchored to building structure.

E. Fan Motor: Comply with requirements in SECTION 15055 - MOTORS.

2.04 COILS:

A. Supply-Air Refrigerant Coil:

1. Copper-plate fin and seamless internally grooved copper tube in steel casing with equalizing-type vertical distributor.

2. Polymer strip shall prevent all copper coils from contacting steel coil frame or condensate pan.

3. Coil Split: Interlaced.

4. Condensate Drain Pan: Galvanized steel with corrosion-resistant coating formed with pitch and drain connections complying with ASHRAE 62.

B. Outdoor-Air Refrigerant Coil:

1. Copper-plate fin and seamless internally grooved copper tube in steel casing with equalizing-type vertical distributor.

2. Polymer strip shall prevent all copper coil from contacting steel coil frame or condensate pan.

2.05 REFRIGERANT CIRCUIT COMPONENTS:

A. Number of Refrigerant Circuits: One.

B. Compressor: Hermetic, reciprocating, mounted on vibration isolators; with internal overcurrent and high-temperature protection, internal pressure relief, and crankcase heater.

C. Refrigeration Specialties:

1. Refrigerant Charge: R-410A.

2. Expansion valve with replaceable thermostatic element.

3. Refrigerant filter/dryer.

4. Manual-reset high-pressure safety switch.

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5. Automatic-reset low-pressure safety switch.

6. Minimum off-time relay.

7. Automatic-reset compressor motor thermal overload.

8. Brass service valves installed in compressor suction and liquid lines.

9. Low-ambient kit high-pressure sensor.

10. Four-way reversing valve with a replaceable magnetic coil, thermostatic expansion valves with bypass check valves, and a suction line accumulator.

2.06 HEATING COILS:

A. Water Coil: Copper tube, with mechanically bonded aluminum fins spaced no closer than 0.1 inch (2.5 mm); leak tested to 300 psig (2070 kPa) underwater; and having a 2-position control valve.

2.07 AIR FILTRATION:

A. Minimum arrestance according to ASHRAE 52.1, and a minimum efficiency reporting value

(MERV) according to ASHRAE 52.2.

1. Pleated: Minimum 90 % arrestance, and MERV 8.

2.08 DAMPERS:

A. Outdoor- and Return-Air Mixing Dampers: Parallel- or opposed-blade galvanized-steel dampers mechanically fastened to cadmium plated for galvanized-steel operating rod in reinforced cabinet. Connect operating rods with common linkage and interconnect linkages so dampers operate simultaneously.

1. Damper Motor: Modulating with adjustable minimum position.

2. Relief-Air Damper: Gravity actuated with bird screen and hood.

2.09 ELECTRICAL POWER CONNECTION:

A. Provide for single connection of power to unit with unit-mounted disconnect switch accessible from outside unit and control-circuit transformer with built-in overcurrent protection.

2.10 CONTROLS:

A. Basic Unit Controls:

1. Control-voltage transformer.

2. Wall-mounted thermostat or sensor with the following features:

a. Heat-cool-off switch.

b. Fan on-auto switch.

c. Fan-speed switch.

d. Automatic changeover.

e. Adjustable deadband.

f. Concealed set point.

g. Concealed indication.

h. Degree F indication.

i. Unoccupied-period-override push button.

j. Data entry and access port to input temperature set points, occupied and unoccupied periods, and output room temperature, supply-air temperature, operating mode, and status.

3. Remote Wall-Mounted Annunciator Panel for Each Unit:

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a. Lights to indicate power on, cooling, heating, fan running, filter dirty, and unit alarm or failure.

b. DDC controller or programmable timer and interface with HVAC instrumentation and control system.

c. Digital display of outdoor-air temperature, supply-air temperature, return-air temperature, economizer damper position, indoor-air quality, and control parameters.

B. DDC Controller:

1. Controller shall have volatile-memory backup.

2. Safety Control Operation:

a. Smoke Detectors: Stop fan and close outdoor-air damper if smoke is detected.

Provide additional contacts for alarm interface to fire alarm control panel.

b. Firestats: Stop fan and close outdoor-air damper if air greater than 130oF (54oC) enters unit. Provide additional contacts for alarm interface to fire alarm control panel.

c. Fire Alarm Control Panel Interface: Provide control interface to coordinate with operating sequence described in SECTION 16721 - FIRE ALARM SYSTEMS.

d. Low-Discharge Temperature: Stop fan and close outdoor-air damper if supply air temperature is less than 40oF (4oC).

e. Defrost Control for Condenser Coil: Pressure differential switch to initiate defrost sequence.

3. Scheduled Operation: Occupied and unoccupied periods on seven-day clock with a minimum of two programmable periods per day.

4. Unoccupied Period:

a. Heating Setback: 50oF (10 oC).

b. Cooling Setback: System off.

c. Override Operation: Two hours.

5. Supply Fan Operation:

a. Occupied Periods: Run fan continuously.

b. Unoccupied Periods: Cycle fan to maintain setback temperature.

6. Refrigerant Circuit Operation:

a. Occupied Periods: Cycle or stage compressors, and operate hot-gas bypass to match compressor output to cooling load to maintain room temperature. Cycle condenser fans to maintain maximum hot-gas pressure. Operate low-ambient control kit to maintain minimum hot-gas pressure.

b. Unoccupied Periods: Compressors off.

c. Switch reversing valve for heating or cooling mode on air-to-air heat pump.

C. Fixed Minimum Outdoor-Air Damper Operation:

a. Occupied Periods: Open to 25%.

b. Unoccupied Periods: Close the outdoor-air damper.

D. Interface Requirements for HVAC Instrumentation and Control System:

1. Interface relay for scheduled operation.

2. Interface relay to provide indication of fault at the central workstation and diagnostic code storage.

3. Provide BACnet or LonWorks compatible interface for central HVAC control workstation for the following:

a. Adjusting set points.

b. Monitoring supply fan start, stop, and operation.

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c. Inquiring data to include outdoor-air damper position, supply- and room-air temperature.

d. Monitoring occupied and unoccupied operations.

e. Monitoring constant and variable motor loads.

f. Monitoring variable-frequency drive operation.

g. Monitoring cooling load.

h. Monitoring economizer cycles.

i. Monitoring air-distribution static pressure and ventilation air volume.

2.11 ACCESSORIES:

A. Low-ambient kit using staged or variable-speed condenser fans for operation down to 0oF

(-17.7oC).

B. Filter differential pressure switch with sensor tubing on either side of filter. Set for final filter pressure loss.

C. Hail guards of galvanized steel, painted to match casing.

PART 3 - EXECUTION

3.01 EXAMINATION:

A. Examine substrates, areas, and conditions, with Installer present, for compliance with requirements for installation tolerances and other conditions affecting performance of RTUs.

B. Examine roughing-in for RTUs to verify actual locations of piping and duct connections before equipment installation.

C. Examine roofs for suitable conditions where RTUs will be installed.

D. Proceed with installation only after unsatisfactory conditions have been corrected.

3.02 CONNECTIONS:

A. Install condensate drain, minimum connection size, with trap and indirect connection to nearest roof drain or area drain.

B. Install piping adjacent to RTUs to allow service and maintenance.

C. 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 at top of roof curb.

2. Remove roof decking only as required for passage of ducts. Do not cut out decking under entire roof curb.

3. Connect supply ducts to RTUs with flexible duct connectors specified in SECTION

15820 - DUCT ACCESSORIES.

4. Install return-air duct continuously through roof structure.

3.03 FIELD QUALITY CONTROL:

A. Manufacturer's Field Service: Engage a factory-authorized service representative to inspect, test, and adjust components, assemblies, and equipment installations, including connections.

Report results in writing.

B. Perform tests and inspections and prepare test reports.

1. Manufacturer's Field Service: Engage a factory-authorized service representative to inspect components, assemblies, and equipment installations, including connections, and to assist in testing. Report results in writing.

C. Tests and Inspections:

SECTION 15732 REPAIR WING HEADQUARTERS, BLDG 706

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1. After installing RTUs and after electrical circuitry has been energized, test units for compliance with requirements.

2. Inspect for and remove shipping bolts, blocks, and tie-down straps.

3. Operational Test: After electrical circuitry has been energized, start units to confirm proper motor rotation and unit operation.

4. Test and adjust controls and safeties. Replace damaged and malfunctioning controls and equipment.

D. Remove and replace malfunctioning units and retest as specified above.

3.04 STARTUP SERVICE:

A. Engage a factory-authorized service representative to perform startup service.

B. Complete installation and startup checks according to manufacturer's written instructions and do the following:

1. Inspect for visible damage to unit casing.

2. Inspect for visible damage to furnace combustion chamber.

3. Inspect for visible damage to compressor, coils, and fans.

4. Inspect internal insulation.

5. Verify that labels are clearly visible.

6. Verify that clearances have been provided for servicing.

7. Verify that controls are connected and operable.

8. Verify that filters are installed.

9. Clean condenser coil and inspect for construction debris.

10. Verify lubrication on fan and motor bearings.

11. Inspect fan-wheel rotation for movement in correct direction without vibration and binding.

12. Adjust fan belts to proper alignment and tension.

13. Start unit according to manufacturer's written instructions.

a. Start refrigeration system.

b. Do not operate below recommended low-ambient temperature.

c. Complete startup sheets and attach copy with Contractor's startup report.

14. Inspect and record performance of interlocks and protective devices; verify sequences.

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

16. Calibrate thermostats.

17. Adjust and inspect high-temperature limits.

18. Inspect outdoor-air dampers for proper stroke and interlock with return-air dampers.

19. Start refrigeration system and measure and record the following when ambient is a minimum of 15oF (8oC) above return-air temperature:

a. Coil leaving-air, dry- and wet-bulb temperatures.

b. Coil entering-air, dry- and wet-bulb temperatures.

c. Outdoor-air, dry-bulb temperature.

d. Outdoor-air-coil, discharge-air, dry-bulb temperature.

20. Inspect controls for correct sequencing of heating, mixing dampers, refrigeration, and normal and emergency shutdown.

21. Measure and record the following minimum and maximum airflows. Plot fan volumes on fan curve.

a. Supply-air volume.

b. Return-air volume.

c. Relief-air volume.

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d. Outdoor-air intake volume.

22. Simulate maximum cooling demand and inspect the following:

a. Compressor refrigerant suction and hot-gas pressures.

b. Short circuiting of air through condenser coil or from condenser fans to outdoor-air intake.

23. Verify operation of remote panel including pilot-light operation and failure modes.

Inspect the following:

a. Low-temperature safety operation.

b. Filter high-pressure differential alarm.

c. Economizer to minimum outdoor-air changeover.

d. Smoke and firestat alarms.

24. After startup and performance testing and prior to Substantial Completion, replace existing filters with new filters.

3.05 CLEANING AND ADJUSTING:

A. Occupancy Adjustments: When requested within 12 months of date of Substantial

Completion, provide on-site assistance in adjusting system to suit actual occupied conditions.

Provide up to two visits to site during other-than-normal occupancy hours for this purpose.

B. After completing system installation and testing, adjusting, and balancing RTU and air-distribution systems, clean filter housings and install new filters.

3.06 DEMONSTRATION:

A. Engage a factory-authorized service representative to train Owner's maintenance personnel to adjust, operate, and maintain RTUs. Refer to DIVISION 1.

END OF SECTION 15732