15725 Add 2.DOC

Interior Renovations at U.S. Courthouse

GSA Number: GS-03P-98-CDC-0019

Pittsburgh, Pennsylvania

Copyright 1999 (R 03/02), The American Institute of Architects (AIA)

SECTION 15725

MODULAR INDOOR AIR-HANDLING UNITS

Verify that Section titles referenced in this Section are correct for this Project's Specifications; Section titles may have changed.

PART 1 - GENERAL

1.1 RELATED DOCUMENTS

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

B. Related Sections include the following: Refer to specification 15910 Commissioning for additional requirements.

1.2 SUMMARY

A. This Section includes constant-volume and variable volume, modular air-handling units with coils for indoor installations. The units are intended to be installed as “knock-down” units, installed in individual components assembled at specific location in the building.

1.3 SUBMITTALS

A. Product Data: For each type of modular indoor air-handling unit indicated. Include the following:

1. Certified fan-performance curves with system operating conditions indicated.

2. Certified fan-sound power ratings.

3. Certified coil-performance ratings with system operating conditions indicated.

4. Motor ratings, electrical characteristics, and motor and fan accessories.

5. Material gages and finishes.

Retain subparagraphs below if items are furnished as parts of modular indoor air-handling units.

6. Filters with performance characteristics.

7. Dampers, including housings, linkages, and operators.

Retain paragraph and subparagraphs below if products are required to withstand specific design loads and Architect has either delegated design responsibility to Contractor or wants to review structural data as another way to verify product's compliance with performance requirements. Professional engineer qualifications are specified in Division 1 Section "Quality Requirements."

Retain paragraph below if Project involves unusual coordination requirements.

B. Coordination Drawings: Submit with Shop Drawings. Show mechanical-room layout and relationships between components and adjacent structural and mechanical elements. Show support locations, type of support, and weight on each support. Indicate and certify field measurements.

Retain paragraph and subparagraphs below if required by seismic criteria applicable to Project. Coordinate with Division 15 Section "Mechanical Vibration and Seismic Controls" and with seismic-related requirements in Part 3 of this Section.

Delete below if manufacturer is not required, in Part 3 "Field Quality Control" Article, to provide or perform field quality-control testing.

C. Field Quality-Control Test Reports: From manufacturer.

1.4 QUALITY ASSURANCE

A. Source Limitations: Obtain modular indoor air-handling units through one source from a single manufacturer.

Retain first paragraph below to allow drawing details based on one manufacturer's product to establish requirements and still allow competition. Coordinate with Division 1 requirements.

B. Product Options: Drawings indicate size, profiles, and dimensional requirements of modular indoor air-handling units and are based on the specific system indicated. Refer to Division 1 Section "Product Requirements."

C. 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.

D. NFPA Compliance: Modular indoor air-handling units and components shall be designed, fabricated, and installed in compliance with NFPA 90A, "Installation of Air Conditioning and Ventilating Systems."

Units from manufacturers that do not participate in ARI's certification program might meet the requirements in this Section; delete first paragraph below if not required.

E. ARI Certification: Modular indoor air-handling units and their components shall be factory tested according to ARI 430, "Central-Station Air-Handling Units," and shall be listed and labeled by ARI.

F. Comply with NFPA 70.

1.5 COORDINATION

A. Prior to Shop drawing submittal and acquisition of the air handling units the contractor shall coordinate size of unit components with access through building to final assembly point.

B. Contractor shall verify in field all clearances required to transport the air handling unit components through building with out disruption or removal of existing walls, or doors not previously defined in the scope documents and drawings.

C. Coordinate size and location of concrete bases. Cast anchor-bolt inserts into bases. Concrete, reinforcement, and formwork requirements are specified in Division 3.

D. Coordinate installation of roof curbs, equipment supports, and roof penetrations. These items are specified in Division 7 Section "Roof Accessories."

E. Coordinate size and location of structural-steel support members.

1.6 EXTRA MATERIALS

Extra materials may not be allowed for publicly funded projects.

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.

Revise subparagraphs below to suit Project.

1. Filters: One set for each modular indoor air-handling unit.

2. Fan Belts: One set for each modular indoor air-handling unit fan.

3. Gaskets: One set for each access door.

PART 2 - PRODUCTS

2.1 MANUFACTURERS

See Editing Instruction No. 1 in the Evaluations for cautions about naming manufacturers and products.

Retain above for nonproprietary or below for semiproprietary specification. Refer to Division 1 Section "Product Requirements."

A. Manufacturers: Subject to compliance with requirements, provide products by one of the following:

1. York International Corporation. (Basis of design)

2. Carrier; Div. of United Technologies Corp.

3. Trane Company (The); Worldwide Applied Systems Group.

2.2 MANUFACTURED UNITS

Revise this Article to eliminate features not required.

A. Modular indoor air-handling units shall be factory assembled and consist of fans, motor and drive assembly, coils, damper, plenums, filters, condensate pans, mixing dampers, control devices, and accessories.

2.3 CABINET

A. Materials: Formed and reinforced double-wall insulated panels, fabricated to allow removal for access to internal parts and components, with joints between sections sealed.

1. Outside Casing: Galvanized steel, 0.0516 inch (1.3 mm)thick.

2. Inside Casing: Galvanized steel, 0.0276 inch (0.7 mm) thick.

3. Floor Plate: Galvanized steel, 0.1382 inch (3.5 mm) thick.

B. Cabinet Insulation: Comply with NFPA 90A or NFPA 90B.

1. Materials: ASTM C 1071 with coated surface exposed to airstream to prevent erosion of glass fibers.

2. Thickness: 2 inches (50 mm).

3. Thermal Conductivity (k-Value): 0.26 at 75 deg F (0.037 at 24 deg C) mean temperature.

4. Fire-Hazard Classification: Maximum flame-spread index of 25 and smoke-developed index of 50, when tested according to ASTM C 411.

5. Liner Adhesive: Comply with NFPA 90A or NFPA 90B and ASTM C 916.

6. Mechanical Fasteners: Galvanized steel, suitable for adhesive attachment, mechanical attachment, or welding attachment to duct without damaging liner when applied as recommended by manufacturer and without causing leakage in cabinet.

7. Location and Application: Factory applied with adhesive and mechanical fasteners to the internal surface of section panels downstream from and including the cooling coil section.

Retain subparagraph above or below.

8. Location and Application: Encased between outside and inside casing.

C. Access Panels and Doors: Same materials and finishes as cabinet, complete with hinges, latches, handles, and gaskets. Inspection and access panels and doors shall be sized and located to allow periodic maintenance and inspections. Provide access panels and doors in the following locations:

1. Fan Section: Doors.

2. Access Section: Doors.

3. Coil Section: Inspection panel.

4. Damper Section: Doors.

5. Filter Section: Doors to allow periodic removal and installation of filters.

D. Condensate Drain Pans: Formed sections of stainless-steel sheet complying with requirements in ASHRAE 62. Fabricate pans with slopes in two planes to collect condensate from cooling coils (including coil piping connections and return bends) and humidifiers when units are operating at maximum catalogued face velocity across cooling coil.

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

2. Drain Connections: Both ends of pan.

3. Pan-Top Surface Coating: Elastomeric compound.

4. Units with stacked coils shall have an intermediate drain pan or drain trough to collect condensate from top coil.

2.4 FAN SECTION

A. Fan-Section Construction: Belt-driven centrifugal fans consisting of housing, wheel, fan shaft, bearings, motor and disconnect switch, drive assembly, and support structure and equipped with formed-steel channel base for integral mounting of fan, motor, and casing panels. Mount fan with vibration isolation.

B. Centrifugal Fan Housings: Formed- and reinforced-steel panels to make curved scroll housings with shaped cutoff, spun-metal inlet bell, and access doors or panels to allow entry to internal parts and components.

1. Panel Bracing: Steel angle- or channel-iron member supports for mounting and supporting fan scroll, wheel, motor, and accessories.

2. Performance Class: AMCA 99-2408, Class II.

3. Horizontal Flanged Split Housing: Bolted construction.

4. Plug Fans: With steel cabinet. Fabricate without fan scroll and volute housing.

C. Fan Assemblies: Statically and dynamically balanced and designed for continuous operation at maximum rated fan speed and motor horsepower.

Select fan-blade style from first four paragraphs and associated subparagraphs below. Some wheels are not available in all sizes. Indicate fan-blade type in an equipment schedule.

Usually only high-pressure fan wheels have aluminum construction. Cast-steel hub is common on AMCA 99-2408, Class III fans.

D. Forward-Curved Fan Wheels: Black-enamel or galvanized-steel construction with inlet flange, backplate, and shallow blades with inlet and tip curved forward in direction of airflow and mechanically secured to flange and backplate; cast-steel hub swaged to backplate and fastened to shaft with set screws.

E. Airfoil-Fan Wheels: Steel construction with smooth-curved inlet flange, heavy backplate, and hollow die-formed airfoil-shaped blades continuously welded at tip flange and backplate; cast-iron or cast-steel hub riveted to backplate and fastened to shaft with set screws.

F. Shafts: Statically and dynamically balanced and designed for continuous operation at maximum rated fan speed and motor horsepower, with final alignment and belt adjustment made after installation.

1. Turned, ground, and polished hot-rolled steel with keyway. Ship with a protective coating of lubricating oil.

2. Designed to operate at no more than 70 percent of first critical speed at top of fan's speed range.

Retain one of first three paragraphs and associated subparagraphs below or retain all and indicate appropriate types in an equipment schedule. Other bearing types may be available; those specified below may not be available from all manufacturers.

G. Prelubricated and Sealed Shaft Bearings: Self-aligning, pillow-block-type ball bearings.

1. Ball-Bearing Rating Life: ABMA 9, L10 of 120,000 hours.

H. Grease-Lubricated Shaft Bearings: Self-aligning, pillow-block-type, tapered roller bearings with double-locking collars and two-piece, cast-iron housing.

1. Roller-Bearing Rating Life: ABMA 11, L10 of 120,000 hours.

I. Grease-Lubricated Shaft Bearings: Self-aligning, pillow-block-type, ball or roller bearings with adapter mount and two-piece, cast-iron housing.

Retain appropriate bearing life from two subparagraphs below. Bearing life typically provided by manufacturers is either 50,000 or 120,000 hours.

1. Ball-Bearing Rating Life: ABMA 9, L10 of 120,000 hours.

2. Roller-Bearing Rating Life: ABMA 11, L10 of 120,000 hours.

J. Belt Drives: Factory mounted, with final alignment and belt adjustment made after installation and with 1.5 service factor based on fan motor.

1. Pulleys: Cast iron or cast steel with split, tapered bushing; dynamically balanced at factory.

5-hp limit in first subparagraph below is standard with many manufacturers but is a designer's choice.

2. Motor Pulleys: Adjustable pitch for use with 5-hp motors and smaller; fixed pitch for use with motors larger than 5 hp. Select pulley so pitch adjustment is at the middle of adjustment range at fan design conditions.

3. Belts: Oil resistant, nonsparking, and nonstatic; matched for multiple belt drives.

4. Belt Guards: Fabricate to OSHA/SMACNA requirements; 0.1046-inch- (2.7-mm-) thick, 3/4-inch (20-mm) diamond-mesh wire screen welded to steel angle frame or equivalent; prime coated. Provide belt guards for motors mounted on outside of cabinet.

5. Motor Mount: Adjustable for belt tensioning.

Revise vibration-control requirements below to suit Project.

K. Vibration Control: Install fans on open-spring vibration isolators having a minimum of 1-inch (25-mm) static deflection and side snubbers.

L. Fan-Section Source Quality Control:

1. Sound Power Level Ratings: Comply with AMCA 301, "Methods for Calculating Fan Sound Ratings from Laboratory Test Data." Test fans according to AMCA 300, "Reverberant Room Method for Sound Testing of Fans." Fans shall bear AMCA-certified sound ratings seal.

2. Factory test fan performance for flow rate, pressure, power, air density, rotation speed, and efficiency. Establish ratings according to AMCA 210, "Laboratory Methods of Testing Fans for Rating."

2.5 MOTORS

Motor characteristics such as NEMA designation, temperature rating, service factor, enclosure type, and efficiency are specified in Division 15 Section "Motors." If different characteristics are required, add paragraphs below to suit Project.

A. General: Comply with requirements in Division 15 Section "Motors."

B. Noise Rating: Quiet.

2.6 COILS

A. Coil Sections: Common or individual, insulated, galvanized-steel casings for heating and cooling coils. Design and construct to facilitate removal and replacement of coil for maintenance and to ensure full airflow through coils.

Retain one of three options in paragraph below.

B. Water Coils: Continuous circuit coil fabricated according to ARI 410 .

Retain first subparagraph and associated subparagraph below for face-and-bypass dampers.

1. Piping Connections: Threaded, on same end.

Retain one of four options in subparagraph below.

2. Tubes: Copper.

Delete fin spacing in first subparagraph below if in a schedule.

3. Fins: Aluminum

4. Fin and Tube Joint: Mechanical bond.

Retain one of four options in subparagraph below.

5. Headers: Fabricated steel with brazed joints, prime coated.

Retain one of two "Frames" subparagraphs below.

6. Frames: Galvanized-steel channel frame, 0.052 inch (1.3 mm).

7. Frames: Stainless steel, 0.0625 inch (1.58 mm).

8. Ratings: Design tested and rated according to ASHRAE 33 and ARI 410.

Pressure and temperature ratings in first subparagraph below are standard for most copper tube coils. Other materials have different ratings; edit to suit Project.

a. Working-Pressure Ratings: 200 psig (1380 kPa), 325 deg F (163 deg C).

9. Source Quality Control: Test to 300 psig (2070 kPa) and to 200 psig (1380 kPa) underwater.

Single-tube coil is also available. Specify same-end connections if freeze protection is required.

2.7 DAMPERS

Low-leakage dampers in this Article are more expensive than other types.

A. General: Leakage rate, according to AMCA 500, "Laboratory Methods for Testing Dampers for Rating," shall not exceed 2 percent of air quantity at 2000-fpm (10-m/s) face velocity through damper and 4-inch wg (1000-Pa) pressure differential.

B. Damper Operators: electric specified in Division 15 Section "HVAC Instrumentation and Controls."

C. Low-Leakage, Outside-Air Dampers: Double-skin, airfoil-blade galvanized-steel dampers with compressible jamb seals and extruded-vinyl blade edge seals, in opposed-blade arrangement with steel operating rods rotating in sintered bronze or nylon bearings mounted in a single galvanized-steel frame, and with operating rods connected with a common linkage. Leakage rate shall not exceed 5 cfm/sq. ft. (0.22 L/s per sq. m) at 1-inch wg (250 Pa) and 9 cfm/sq. ft. (0.4 L/s per sq. m) at 4-inch wg (1.0 MPa).

Mixing box in first paragraph below is standard quality. Low-leakage dampers are available from some manufacturers and from manufacturers of temperature-control equipment.

D. Mixing Boxes: Parallel-blade galvanized-steel dampers mechanically fastened to steel operating rod in reinforced, galvanized-steel cabinet. Connect operating rods with common linkage and interconnect linkages so dampers operate simultaneously.

E. Combination Filter and Mixing Box: Parallel-blade galvanized-steel dampers mechanically fastened to steel operating rod in reinforced, galvanized-steel cabinet. Connect operating rods with common linkage and interconnect linkages so dampers operate simultaneously. Cabinet support members shall hold 2-inch- (50-mm-) thick, pleated, flat permanent or throwaway filters. Provide hinged access panels or doors to allow removal of filters from both sides of unit.

2.8 FILTER SECTION

A. Filters: Comply with NFPA 90A.

B. Filter Section: Provide filter holding frames arranged for flat or angular orientation, with access doors on both sides of unit. Filters shall be removable from one side.

C. Disposable Panel Filters: Factory-fabricated, viscous-coated, flat-panel-type, disposable air filters with holding frames.

1. Media: Interlaced glass fibers sprayed with nonflammable adhesive.

2. Frame: Galvanized steel with metal grid on outlet side, steel rod grid on inlet side, hinged, and with pull and retaining handles.

3. Duct-Mounting Frames: Welded, galvanized steel with gaskets and fasteners, suitable for bolting together into built-up filter banks.

D. Extended-Surface, Disposable Panel Filters: Factory-fabricated, dry, extended-surface filters with holding frames.

1. Media: Fibrous material formed into deep-V-shaped pleats and held by self-supporting wire grid.

Select one of three options in first subparagraph below.

2. Media and Media-Grid Frame: Nonflammable cardboard.

3. Duct-Mounting Frames: Welded, galvanized steel with gaskets and fasteners, suitable for bolting together into built-up filter banks.

PART 3 - EXECUTION

3.1 EXAMINATION

A. Examine areas and conditions for compliance with requirements for installation tolerances and other conditions affecting performance.

B. Examine roughing-in of steam, hydronic, and condensate drainage piping systems and electrical services to verify actual locations of connections before installation.

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

3.2 INSTALLATION

A. Concrete Bases: Install floor mounting units on 4-inch- (100-mm-) high concrete bases. See Division 15 Section "Basic Mechanical Materials and Methods" for concrete base materials and fabrication requirements.

B. Install modular indoor air-handling units with the following vibration control devices.

Select from four subparagraphs below or edit to suit Project and equipment requirements. Refer to Division 15 Section "Mechanical Vibration and Seismic Controls" for other types and applications of vibration-control devices.

1. Units with Internally Isolated Fans: Secure units to anchor bolts installed in concrete bases.

2. Floor-Mounted Units: Support on concrete bases using neoprene pads. Secure units to anchor bolts installed in concrete bases.

3. Floor-Mounted Units: Support on concrete bases using housed-spring isolators. Secure units to anchor bolts installed in concrete bases.

4. Suspended Units: Suspend units from structural-steel support frame using threaded steel rods and spring hangers.

C. Arrange installation of units to provide access space around modular indoor air-handling units for service and maintenance.

3.3 CONNECTIONS

Coordinate piping installations and specialty arrangements with schematics on Drawings and with requirements specified in piping systems. If Drawings are explicit enough, these requirements may be reduced or omitted.

A. Piping installation requirements are specified in other Division 15 Sections. Drawings indicate general arrangement of piping, fittings, and specialties.

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

Flexible connections in first paragraph below may not be necessary. Verify requirements with Project conditions.

C. Connect piping to modular indoor air-handling units mounted on vibration isolators with flexible connectors.

D. Connect condensate drain pans using NPS 1-1/4 (DN 32), Type M copper tubing. Extend to nearest equipment or floor drain. Construct deep trap at connection to drain pan and install cleanouts at changes in direction.

E. Hot- and Chilled-Water Piping: Comply with applicable requirements in Division 15 Section "Hydronic Piping." Connect to supply and return coil tappings with shutoff or balancing valve and union or flange at each connection.

F. Steam and Condensate Piping: Comply with applicable requirements in Division 15 Section "Steam and Condensate Piping." Connect to supply and return coil tappings with shutoff valve and union or flange at each connection.

Coordinate duct installations and specialty arrangements with schematics on Drawings and with requirements specified in duct and duct accessory Specifications. If Drawings are explicit enough, these requirements may be reduced or omitted.

G. Duct installation and connection requirements are specified in other Division 15 Sections. Drawings indicate general arrangement of ducts and duct accessories. Make final duct connections with flexible connections.

H. Electrical: Comply with applicable requirements in Division 16 Sections for power wiring, switches, and motor controls.

I. Ground equipment according to Division 16 Section "Grounding and Bonding."

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

3.4 FIELD QUALITY CONTROL

A. Manufacturer's Field Service: Engage a factory-authorized service representative to inspect field-assembled components and equipment installation, including piping and electrical connections. Report results in writing.

1. Leak Test: After installation, fill water and steam coils with water and test coils and connections for leaks. Repair leaks and retest until no leaks exist.

2. Fan Operational Test: After electrical circuitry has been energized, start units to confirm proper motor rotation and unit operation. Remove malfunctioning units, replace with new units, and retest.

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

3.5 STARTUP SERVICE

Delete first paragraph below if factory-authorized service representative is not required.

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

B. Final Checks before Startup: Perform the following:

1. Verify that shipping, blocking, and bracing are removed.

2. Verify that unit is secure on mountings and supporting devices and that connections to piping, ducts, and electrical systems are complete. Verify that proper thermal-overload protection is installed in motors, starters, and disconnect switches.

3. Perform cleaning and adjusting specified in this Section.

4. Disconnect fan drive from motor, verify proper motor rotation direction, and verify free fan wheel rotation and smooth bearing operations. Reconnect fan drive system, align belts, and install belt guards.

5. Lubricate bearings, pulleys, belts, and other moving parts with factory-recommended lubricants.

6. Set zone dampers to fully open position for each zone.

7. Set outside- and return-air mixing dampers to minimum outside-air setting.

8. Comb coil fins for parallel orientation.

9. Install clean filters.

10. Verify that manual and automatic volume control and fire and smoke dampers in connected duct systems are in fully open position.

C. Starting procedures for modular indoor air-handling units include the following:

1. Energize motor; verify proper operation of motor, drive system, and fan wheel. Adjust fan to indicated rpm. Replace fan and motor pulleys as required to achieve design conditions.

2. Measure and record motor electrical values for voltage and amperage.

3. Manually operate dampers from fully closed to fully open position and record fan performance.

D. Refer to Division 15 Section "Testing, Adjusting, and Balancing" for modular indoor air-handling system testing, adjusting, and balancing.

3.6 ADJUSTING

A. Adjust damper linkages for proper damper operation.

3.7 CLEANING

A. Clean modular indoor air-handling units internally, on completion of installation, according to manufacturer's written instructions. Clean fan interiors to remove foreign material and construction dirt and dust. Vacuum clean fan wheels, cabinets, and coils entering air face.

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

3.8 DEMONSTRATION

A. Engage a factory-authorized service representative to train Owner's maintenance personnel to adjust, operate, and maintain modular indoor air-handling units. Refer to Division 1 Section "Demonstration and Training."

END OF SECTION 15725

October 26, 2010

Addendum 2 15725- 2 Modular Indoor Air-Handling Units