5-6730-23 73 13-Modular Central-Station Air-Handling Units.pdf

VAN BUREN INTERMEDIATE SCHOOL DISTRICT

5-6730 VBISD CTE IMPROVEMENTS

A/E PROJECT 5-6730

Copyright GMB 2025 SECTION 23 73 13

MODULAR CENTRAL-STATION AIR-HANDLING UNITS

SECTION 23 73 13 - MODULAR CENTRAL-STATION AIR-HANDLING UNITS

(ADDENDUM 002)

PART 1 GENERAL

1.1 SECTION INCLUDES

A. Casing construction.

B. Fan section.

C. Coil section.

D. Filter and air cleaner section.

E. Damper section.

F. Airflow measurement.

G. Access section.

H. Turning and discharge plenum section.

I. Electrical power connections J. Controls.

1.2 RELATED REQUIREMENTS

A. Section 23 05 48 - Vibration and Seismic Controls for HVAC.

B. Section 23 05 93 - Testing, Adjusting, and Balancing for HVAC.

C. Section 23 07 19 - HVAC Piping Insulation.

D. Section 23 09 13 - Instrumentation and Control Devices for HVAC.

E. Section 23 09 93 - Sequence of Operations for HVAC Controls.

F. Section 23 33 00 - Air Duct Accessories: Flexible duct connections.

G. Section 23 40 00 - HVAC Air Cleaning Devices.

H. Section 26 05 83 - Wiring Connections: Electrical characteristics and wiring connections.

1.3 REFERENCE STANDARDS

A. ABMA STD 9 - Load Ratings and Fatigue Life for Ball Bearings.

B. AHRI 410 - Forced-Circulation Air-Cooling and Air-Heating Coils.

C. AMCA (DIR) - (Directory of) Products Licensed Under AMCA International Certified Ratings

Program.

D. AMCA 99 - Standards Handbook.

E. AMCA 210 - Laboratory Methods of Testing Fans for Certified Aerodynamic Performance

Rating.

F. AMCA 300 - Reverberation Room Methods of Sound Testing of Fans.

G. AMCA 301 - Methods for Calculating Fan Sound Ratings from Laboratory Test Data.

H. AMCA 500-D - Laboratory Methods of Testing Dampers for Rating.

I. ASHRAE Std 62.1 - Ventilation for Acceptable Indoor Air Quality.

J. ASHRAE Std 90.1 I-P - Energy Standard for Buildings Except Low-Rise Residential Buildings.

K. NFPA 70 - National Electrical Code.

L. NFPA 90A - Standard for the Installation of Air-Conditioning and Ventilating Systems.

M. UL (DIR) - Online Certifications Directory.

N. UL 181 - Standard for Factory-Made Air Ducts and Air Connectors.

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1.4 ADMINISTRATIVE REQUIREMENTS

A. Coordinate the work with other trades for installation of roof mounted air handling units on roof curbs.

B. Preinstallation Meeting: Conduct a preinstallation meeting one week prior to the start of the work of this section; require attendance by all affected installers.

C. Sequencing: Ensure that utility connections are achieved in an orderly and expeditious manner.

1.5 SUBMITTALS

A. See Section 01 30 00 - Administrative Requirements for submittal procedures.

B. Product Data:

1. Published Literature: Indicate dimensions, weights, capacities, ratings, gauges and finishes of materials, and electrical characteristics and connection requirements.

2. Filters: Data for filter media, filter performance data, filter assembly, and filter frames.

3. Fans: Performance and fan curves with specified operating point clearly plotted, power, RPM.

4. Sound Power Level Data: Fan outlet and casing radiation at rated capacity.

5. Electrical Requirements: Power supply wiring including wiring diagrams for interlock and control wiring, clearly indicating factory-installed and field-installed wiring.

C. Sustainable Design Documentation: Submit manufacturer's product data on refrigerant used, showing compliance with specified requirements.

D. Shop Drawings: Indicate assembly, unit dimensions, weight loading, required clearances, construction details, field connection details, and electrical characteristics and connection requirements.

E. Manufacturer's Instructions: Include installation instructions.

F. Maintenance Data: Include instructions for lubrication, filter replacement, motor and drive replacement, spare parts lists, and wiring diagrams.

G. Maintenance Materials: Furnish the following for Owner's use in maintenance of project.

1. See Section 01 60 00 - Product Requirements for additional provisions.

2. Extra Fan Belts: One set of each type and size.

3. Gaskets: One set for each access door.

4. Extra Filters: Two sets of each type and size.

1.6 QUALITY ASSURANCE

A. Manufacturer Qualifications: Company specializing in manufacturing the type of products specified in this section, with minimum five years of documented experience.

1.7 DELIVERY, STORAGE, AND HANDLING

A. Accept products on site in factory-fabricated protective containers, with factory-installed shipping skids and lifting lugs. Inspect for damage.

B. Store in clean dry place and protect from weather and construction traffic. Handle carefully to avoid damage to components, enclosures, and finish.

C. Do not operate units until construction is complete and ductwork is clean, filters are in place, bearings lubricated, and fan has been test run under observation.

1.8 WARRANTY

A. See Section 01 78 00 - Closeout Submittals for additional warranty requirements.

B. Provide minimum two year manufacturer warranty covering repair or replacement due to defective materials or workmanship.

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PART 2 PRODUCTS

2.1 MANUFACTURERS

Carrier Global Corporation.

A. Daikin Applied.

B. Dunham-Bush, Inc.

C. Trane Technologies, PLC.

D. York, a brand of Johnson Controls International, PLC.

E. Substitutions: See Section 01 60 00 - Product Requirements.

1. The air handling units have been designed based on specific capacities and characteristics of equipment as indicated on mechanical equipment schedules.

2. When substitution of a different manufacturer or model number, submit sufficient information to demonstrate to Architect that the substitute will have the same or better performance as that specified AND that the related equipment in the system will perform acceptably with the substitute.

3. If the related equipment must be modified to perform acceptably with the substitute, the entity proposing the substitution is responsible for all additional costs due to re-design and provision of different related equipment.

2.2 REGULATORY REQUIREMENTS

A. Comply with NFPA 70.

B. Products Requiring Electrical Connection: Listed and classified by UL (DIR) as suitable for the purpose specified and indicated.

2.3 CASING CONSTRUCTION

A. Full Perimeter Base Rail:

1. Construct of galvanized steel.

2. Provide minimum base rail of 6 inchesand sufficient height to raise unit for external trapping of condensate drain pans.

B. Casing:

1. Constructed of one piece, injection foam insulated, double wall panels.

2. Provide mid-span, no through metal, internal thermal break.

3. Construct outer panels of galvanized steel and inner panels of galvanized steel.

4. Casing Air Pressure Performance Requirements:

a. Able to withstand up to 8 in-wc positive or negative static pressure.

b. Not to exceed 0.0042 inches per inch deflection at 1.5 times design static pressure up to a maximum of plus 8 in-wc in positive pressure sections and minus 8 in-wc in negative pressure sections.

C. Access Doors:

1. Construction, thermal and air pressure performance same as casing.

2. Provide surface mounted handles on ball bearing or stainless steel piano hinged, swing doors. Arrange doors to be opened against airflow. Provide safety latch on doors so that doors do not open uncontrollably. Doors shall be fully removable.

3. Access doors shall have neoprene gasket applied around entire perimeters of panel frames.

D. Unit Flooring: Construct with sufficient strength to support expected people and equipment loads associated with maintenance activities.

E. Casing Leakage: Seal joints and provide airtight access doors so that air leakage does not exceed one percent of design flow at the specified casing pressure.

F. Insulation:

1. Provide minimum thermal thickness of 12 R throughout.

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2. Completely fill panel cavities in each direction to prevent voids and settling.

3. Comply with NFPA 90A.

G. Drain Pan Construction:

1. Provide coil sections with an insulated, double wall, stainless steel drain pan complying with ASHRAE Std 62.1 for indoor air quality and sufficiently sized to collect all condensate.

2. Slope in two planes to promote positive drainage and eliminate stagnate water conditions.

3. Locate outlet of sufficient diameter at lowest point of pan to prevent overflow at normal operating conditions.

4. Provide threaded drain connections constructed of drain pan material, extended sufficient distance beyond the base to accommodate field installed, condensate drain trapping.

H. Marine Lights:

1. Provide factory-mounted, water- and dust-resistant LED fixture(s) in each fan section, with the following characteristics:

a. Non-ferrous metal housing.

b. Glass or polycarbonate lens.

c. Factory wired to a single switch within factory provided service module.

d. Instant on white light with minimum 8,000 hour service life.

2. Provide factory installed service module including GFCI receptacle independent from load side; designed to receive power from single-point power source.

I. Finish:

1. Indoor Units:

a. Provide exterior, G90 galvanized steel panels without paint.

2.4 FAN SECTION

A. Type: Air foil, single width, single inlet, centrifugal plug fan, in accordance with AMCA 99.

B. Performance Ratings: Determined in accordance with AMCA 210 and labeled with AMCA

Certified Rating Seal.

C. Sound Ratings: AMCA 301; tested to AMCA 300 and label with AMCA Certified Sound Rating

Seal.

D. Bearings: Self-aligning, grease lubricated, with lubrication fittings extended to exterior of casing with plastic tube and grease fitting rigidly attached to casing.

E. Mounting:

1. Locate fan and motor internally on welded steel base coated with corrosion resistant paint.

2. Factory-mount fans with manufacturer's standard restrained vibration isolation mounting devices having a minimum static deflection of 1 inch.

3. Factory mount motor on slide rails.

4. Provide access to motor, drive, and bearings through removable casing panels or hinged access doors.

F. External Motor Junction Box: Factory mount NEMA 4 external junction box and connect to extended motor leads from internally mounted motors.

G. Motor Wiring Conduit: Factory wire fan motor wiring to the unit mounted starter-disconnect, variable frequency drive, and external motor junction box.

H. Flexible Duct Connections:

1. For all unit ductwork connections.

2. See Section 23 33 00.

I. Drives:

1. Comply with AMCA 99.

2. Bearings: Heavy duty pillow block type, ball bearings, with ABMA STD 9 L-10 life at

50,000 hours.

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3. Shafts: Solid, hot rolled steel, ground and polished, with key-way, and protectively coated with lubricating oil.

4. Direct Drive: Factory mounted direct drive.

J. Motors:

1. Comply with modular air handling unit requirements and ratings along with requirements of Section 23 05 13.

2. Motor electrical requirements and wiring to comply with requirements of Section 26.

K. Service Receptacle:

1. Provide factory installed service module including GFCI receptacle independent from load side; designed to receive power from single-point power source.

2.5 COIL SECTION

A. Casing: Provide access to both sides of coils. Enclose coils with headers and return bends fully contained within casing. Slide coils into casing through removable end panel with blank off sheets and sealing collars at connection penetrations.

B. Drain Pans: 24 inch downstream of coil and down spouts for cooling coil banks more than one coil high.

C. Eliminators: Three break of galvanized steel, mounted over drain pan.

D. Air Coils:

1. Certify capacities, pressure drops, and selection procedures in accordance with AHRI 410.

E. Fabrication:

1. Tubes: 5/8 inch OD seamless copper expanded into fins, brazed joints.

2. Fins: Aluminum.

3. Casing: Die formed channel frame of galvanized steel.

F. Water Heating Coils:

1. Headers: Cast iron, seamless copper tube, or prime coated steel pipe with brazed joints.

2. Configuration: Drainable, with threaded plugs for drain and vent; serpentine type with return bends on smaller sizes and return headers on larger sizes.

3. Piping Connections: Same end, threaded or flanged.

4. Ratings: 200 psi, 325 degrees F.

2.6 FILTER AND AIR CLEANER SECTION

A. General: Provide filter sections with filter racks, minimum of one access door for filter removal, and filter block-offs to prevent air bypass.

B. Refer to equipment schedule and Section 23 40 00 for filter requirements.

C. Differential Pressure Gauge:

1. Provide factory installed dial type differential pressure gauge, flush mounted with casing outer wall, and fully piped to both sides of each filter to indicate status.

2. Maintain plus/minus 5 percent accuracy within operating limits of 20 degrees F to 120 degrees F.

2.7 DAMPER SECTION

A. Mixing Section: Provide a functional section to support the damper assembly for modulating the volume of outdoor and return air.

B. Damper Actuators to comply with requirements of Section 23 09 13.

C. Damper Blades:

1. Dampers to comply with requirements of Section 23 33 00.

2. Double-skin airfoil design with metal, compressible jamb seals and extruded-vinyl blade-edge seals on each blade.

3. Self-lubricating stainless steel or synthetic sleeve bearings.

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4. Comply with ASHRAE Std 90.1 I-P for rated maximum leakage rate.

5. Provide leakage testing and pressure ratings in compliance with AMCA 500-D test methods.

6. Arrange in parallel or opposed-blade configuration.

2.8 AIRFLOW MEASUREMENT

A. Airflow Measuring to comply with the requirements of Section 23 09 13.

2.9 ACCESS SECTION

A. Provide where indicated on drawings to allow for inspection, cleaning, and maintenance of field-installed components.

B. Construct access doors same as previously specified within this Section.

2.10 TURNING AND DISCHARGE PLENUM SECTION

A. Provide plenum to efficiently turn and discharge air.

1. Scale plenum vertical height to accommodate discharge duct height.

2. Scale plenum horizontal length to accommodate required dimensional constraints.

B. Acoustical Liner for fan an:

1. Fabricate from corrosion-proof, perforated stainless steel with completely encapsulated fiberglass insulation.

2. Prevent breakaway, flake off, or delamination when tested at 9000 fpm in accordance with

UL 181.

2.11 ELECTRICAL POWER CONNECTIONS

A. Air Handling Unit shall have a single connection of power to unit with unit-mounted disconnect switch accessible from outside unit and control-circuit transformer with built-in overcurrent protection.

2.12 CONTROLS

A. Controls shall be field installed by the Temperature Control Contractor. Control devices and sequence of operation to comply with requirements specified in Sections 23 09 13 and 23 09 93.

B. Combination VFD - Disconnects:

1. Provide factory mounted, combination VFD - disconnect for each fan motor.

PART 3 EXECUTION

3.1 INSTALLATION

A. Install in accordance with manufacturer's instructions.

B. Bolt sections together with gaskets.

C. Isolate fan section with flexible duct connections.

D. Install flexible duct connections between fan inlet and discharge ductwork and air handling unit sections. Ensure that metal bands of connectors are parallel with minimum 2 inch flex between ductwork and fan while running.

E. Provide fixed sheaves required for final air balance.

F. Make connections to coils with unions or flanges. Install flexible pipe connectors on units with external vibration isolation. Refer to Section 23 05 48 for additional information.

G. Hydronic Coils:

1. Hydronic Coils: Connect water supply to leaving air side of coil (counterflow arrangement).

2. Provide shut-off valve on supply line and lockshield balancing valve with memory stop and shut-off valve on return line.

3. Locate water supply at bottom of supply header and return water connection at top.

4. Provide manual air vents at high points complete with stop valve.

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5. Ensure water coils are drainable and provide drain connection at low points.

H. Insulate coil headers located outside airflow as specified for piping; see Section 23 07 19.

I. Do not operate fan system for temporary usage until construction is complete and facility is ready for occupancy.

3.2 FIELD QUALITY CONTROL

A. See Section 01 40 00 - Quality Requirements for additional requirements.

B. Coordination Tests and Inspections:

1. Owner or GDK Construction will employ independent Testing, Adjusting, and Balancing agency and Commissioning agency to test and/or inspect modular central-station air handling-unit.

2. Provide access and coordination time as required to accommodate timely performance.

3. See Section 23 05 93 and 23 08 00.

3.3 SYSTEM STARTUP

A. Provide manufacturer's field representative to perform systems startup.

B. Prepare and start equipment and systems in accordance with manufacturers' instructions and recommendations.

C. Adjust all air handling unit and each component for proper operation within manufacturer's published tolerances.

3.4 CLEANING

A. After completing system installation, testing procedures and startup service, clean air handling units internally of all dirt and debris.

B. Comb all damaged coil fins to original manufactured orientation.

C. Install new filters.

3.5 FIELD QUALITY CONTROL

A. See Section 01 40 00 - Quality Requirements for additional requirements.

B. Provide manufacturer's field representative to perform startup service; test, inspect, instruct, and observe field-assembled components and equipment installation, including connections and to assist in field testing. Report results in writing.

1. Leak Test:

a. After installation, fill water and steam coils with water and test for leaks.

b. Charge refrigerant coils with nitrogen and test for leaks.

c. Repair leaks and retest until no leaks exist.

2. Operational Test:

a. After electrical circuitry has been energized, start units to confirm proper motor rotation and unit operation.

b. Test and adjust controls and safeties.

c. Replace damaged and malfunctioning controls and other equipment.

d. Remove and replace malfunctioning air handling unit components and retest as specified above.

3.6 CLOSEOUT ACTIVITIES

A. Demonstrate proper operation of equipment to Owner's designated representative.

B. Demonstration: Demonstrate operation of system to Owner's personnel.

1. Use operation and maintenance data as reference during demonstration.

2. Conduct walking tour of project.

3. Briefly describe function, operation, and maintenance of each component.

C. Training: Train Owner's personnel on operation and maintenance of system.

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1. Use operation and maintenance manual as training reference, supplemented with additional training materials as required. All training shall be video recorded for Owner's usage.

2. Provide minimum of four hours of training.

3. Instructor: Manufacturer's training personnel.

4. Location: At project site.

END OF SECTION