Section 15xxx – SMART CHOICE™ Air Handling Units – Factory Fabricated / Field Assembled

Part 1 - General

1.1      Related Documents

A.       General:  Comply with the General Conditions and all applicable contract documents.

1.2      Work Included - Furnish all labor, material, facilities and tools for a complete and proper installation.  The work of this Section shall include but not be limited to the following:

A.     Air handling units.

B.     Related work specified elsewhere:

1.      Supports and anchors

2.      Meters and gauges

3.      Mechanical insulation

4.      Hydronic piping systems

5.      Steam and condensate piping and specialties

6.      Refrigerant piping and specialties

7.      Sheet metal ductwork

8.      Sound attenuators

9.      Air terminal units

10. Automatic temperature control systems

11. Testing, adjusting and balancing

12. Starters

13. Power wiring

1.3      Submittals

A.       Product Data:  Submit manufacturer’s technical product data for air handling units showing dimensions, weights, capacities, ratings, certified fan performance curves, with operating point clearly indicated, motor electrical characteristics, and finishes of materials, and installation instructions.

B.       Shop Drawings:  Submit shop drawings showing unit dimensions, weight loading, required clearances, field connection details and methods of support.  Draw to a scale of 3/8” to one foot, using same sheet size as contract drawings.  Include dampers and duct connections.

C.      Maintenance Data:  Submit maintenance instructions, including instructions for lubrication, filter replacement, motor and drive replacement, and spare parts list.  Include this data, product data, shop drawings, and wiring diagrams in operating and maintenance manuals; in accordance with requirements of Division 1.

1.4      Quality Assurance

A.       Manufacturer’s Responsibility: Provide factory designed and fabricated air handling units, shipped knocked down for field assembly by the Contractor.  Unit manufacturer  shall have sole source responsibility for the design, factory fabrication and supply of all air handling unit components and equipment as noted below.  Provide air handling units that are a product of an equipment manufacturer regularly engaged in the production of such units. Unit components and equipment fabricated and supplied by the contractor will not be permitted.

B.       Contractor’s Responsibility:  The Contractor shall be responsible for the field assembly of the air handling unit per the instructions and submittal documents supplied by the unit manufacturer.  The Contractor shall be responsible for providing and installing damper actuators and linkage, electrical equipment and wiring, piping, equipment safing and single wall panels.  The Contractor shall provide the unit manufacturer with all field dimensions, mounting locations and duct openings as required to coordinate the design and fabrication of the unit.

C.      Certifications:  Provide certified ratings of units based on tests performed in accordance with ARI 430, “Central-Station Air Handling Units”.

D.      Codes and Standards:  Provide air handling units conforming to the following:

1.        Air Movement and Control Association, Inc. (AMCA):  Comply with applicable AMCA codes including AMCA 210 and 500.

2.        Air-Conditioning and Refrigeration Institute (ARI):  Comply with applicable ARI codes including ARI 410 and 430.

3.        American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE):  Construct and install refrigerant coils in accordance with ASHRAE 15, “Safety Code for Mechanical Refrigeration”.

4.        National Electrical manufacturers Association (NEMA):  Except for motors, provide electrical components required as part of air handling units, which comply with NEMA Standards.

5.        National Fire Protection Association (NFPA):  Provide air handling unit which complies with NFPA 90A, “Standard for the Installation of Air Condition and Ventilating Systems”.  Comply with NFPA 70, “National Electrical Code”, as applicable for installation and electrical connections of ancillary electrical components of air handling units.

6.        Sheet Metal and Air Conditioning Contractors’ National Association, Inc. (SMACNA):  Comply with applicable SMACNA standards including “HVAC Duct Construction Standards - Metal and Flexible”.

7.        Underwriter’s Laboratories, Inc. (UL):  Except for motors, provide electrical components required as part of air handling units, which have been listed and labeled by UL.

1.5      Delivery, Storage and Handling

A.       Delivery:  Deliver air handling unit components on factory-installed shipping skids; pack small components in factory-fabricated protective containers.

B.       Handling:  Handle air handling unit components carefully to avoid damage to components, enclosures, and finishes.  Do not install damaged components; replace and return damaged components to air handling unit manufacturer.

C.      Storage:  Store air handling units in clean dry place and protect from weather and construction traffic.

D.      Unloading:  Comply with manufacturer’s rigging and installation instructions for unloading air handling unit components, and move units to final location.

Part 2 - Products

2.1       Manufacturers

A.       Acceptable manufacturers:  Vibro-Acoustics

2.2      Air Handling Units

A.       General:  Unit shall be supplied in a component form for field assembly.  Scope of supply shall include wall and roof panels, access doors, fans with motors, drives, vibration bases and isolators, coils with coil racks, drain and drip pans, evaporative cooling section with coils and media , flexible connections, dampers, and silencers as required by the contract drawings and schedules

1.        Design unit fans and casings, which are suitable for the maximum, total static pressure of the fans under all conditions.

2.        The entire unit shall be assembled on a 4” high housekeeping pad with 4” high perimeter curbs and equipment pads supplied and waterproofed by the contractor.

3.        The air handling unit/silencer system shall produce a maximum noise level of NC xx in the areas served by the air handling units.

B.       Unit Construction

1.        Wall and Roof Panels:  Panels shall be 4” tongue and groove type.  The exterior sheet shall be a minimum of 18 ga. galvanized steel.  The interior sheet shall be a minimum of 22 ga. galvanized steel.  The interior sheet shall be perforated in all areas, except downstream of the cooling coil and humidifier.  In these areas the interior sheet shall be 304 stainless steel for a distance of 42”.  Panels shall be insulated with 4” 3 lb./ft³ fiberglass.

2.        Removable Panels:  Bolted panels shall be provided for fan and coil removal.  Panels shall be 4” with construction as noted above.

3.        Safing And Single Wall Panels:  All safing and single wall panels shall be 16 ga. galvanized steel, except for the coiling coils where these items shall be 16 ga. 304 stainless steel.  Safing and single wall panels shall be field measured and supplied by the contractor.

4.        Media:  Media shall be incombustible, acoustical quality, shot-free fiberglass insulation with long, resilient fibers bonded with a thermosetting resin.  Fiberglass shall be packed with 15% compression during panel assembly.  Media shall be bacteria and fungus resistant and conform to irregular surfaces.  Media shall not cause or accelerate corrosion of aluminum or steel.  Mineral wool will not be permitted as a substitute for fiberglass.

5.        Access Doors:  Doors shall be provided for each component section.  Doors shall be 4” x  24” wide  x 72” high with the same construction as the acoustic panels, except that the interior sheet shall be solid.  Doors shall be mounted in a 10 ga. galvanized steel angle frame with a single “P” gasket.  Hardware shall include (2) cam-type latches and stainless steel butt hinges.  Doors shall be supplied with 12” x 12” inspection windows, double glazed with ¼” wire-reinforced glass mounted in a neoprene U-gasket.

6.        The acoustical performance of the panels shall be equal to or greater than the following:

Octave Band, Hz                    125     250     500     1000   2000   4000  

Transmission Loss, dB             21       27         37        48        55        55

Absorption Coefficients         0.74    0.9      0.99    0.99      0.9       0.9

7.        The thermal conductance of the insulation shall be less than 0.06 BTU/hr/sq.ft./F at 50 degrees F mean temperature.  The overall thermal conductance of the assembled structure shall not exceed 0.15 BTU/hr/sq. ft./F at 50 degrees F mean temperature.

C.      Fans:  Provide fans conforming to AMCA 210 and rated for the duty noted in the air handling unit schedule.

1.        Acceptable manufacturers: as specified

D.      Motors and Drives:  Provide fan motors with a nameplate rating of not less than 10 percent above the fan brake horsepower and drive loss at maximum capacities at any point on the characteristic curve.

1.        Each motor provided with automatic control shall be capable of making frequent starts as the control device may demand.  Motors without automatic control shall be capable of making not less than 4 starts per hour.

2.        Polyphase shall be of the dripproof, squirrel cage, induction type in accordance with NEMA MG 1.  Polyphase motors shall be single-voltage type or increment starting type. 

E.       Cooling and Hot Water Coils

1.        Coils shall be constructed with 5/8” O.D. copper tubes with 0.020” tube wall thickness.  Fins shall be 0.0075” aluminum.  Coil casing shall be minimum of 16 ga. galvanized steel for heating applications and 304 stainless steel for cooling applications.  Headers shall be non-ferrous barrels with vents and drain connections.

2.        Coil connections are to be extended through the casing wall by the unit manufacturer.

3.        Coils shall be rated and certified to carry the ARI stamp per ARI Standard 410-72.

4.        Acceptable manufacturers:  as specified

F.       Coil Racks, Drain and Drip Pans

1.        Coil racks shall be constructed of 304 stainless steel structural members.  Coil racks shall be designed to permit the removal of individual coil sections without disturbing remaining coils.

2.        In cooling coil sections, the drain pan shall be continuously welded, positively sloping 16 ga. 304 stainless steel pan with a minimum depth of 4” at the drain.  The drain pan shall be insulated with 2” 3 lb./ft³ fiberglass and an 18 ga. galvanized steel cover.

3.        Drip pans shall be continuously welded, positively sloping 18 ga. 304 stainless steel with a minimum depth of 2” at the drain.  Drain piping shall be 304 stainless steel with each drip pan individually piped to the drain pan.

G.      Filters

1.        Filters shall be 2” deep, medium efficiency, pleated, disposable type.  Each filter shall consist of a non-woven cotton and synthetic fabric media, media support grid and enclosing frame.  The filter shall be listed by Underwriters’ Laboratories as Class 2.

2.        Filter media shall have an average efficiency of 25-30% on ASHRAE Test Standard 52-76.  It shall have an average arrestance of 90-92% in accordance with the test standard.

3.        The effective filter media shall not be less than 4.6 ft² of media per 1.0 ft² of filter face area and shall contain not less than 15 pleats per linear foot.

4.        Holding frames shall be face loading type,16 ga. galvanized steel and shall be equipped with gaskets and four spring type positive fasteners.

5.        Filters shall as specified complete with holding frames.

6.        Each filter bank shall be furnished with a pressure differential gauge, with two static pressure tips and vent valves.  Gauges shall be factory mounted on unit casing.

H.       Dampers

1.        Dampers shall be low leakage, air foil blade type.  Frames shall be constructed of 6063T5 extruded aluminum hat channel with hat mounting flanges on both sides of the frame. 

2.        Blades shall be airfoil type extruded aluminum with integral structural reinforcing tube running the full length of each blade.  Blade edge seals shall be extruded vinyl double edge design.  Blade seals shall be locked in extruded blade slots and be easily removable.

3.        Bearings shall be non-corrosive two piece molded synthetic.  Axles shall be square or hexagonal only.  Linkage shall be concealed in the frame.

4.        Damper performance must be based on AMCA Standard 500 in an AMCA approved laboratory.

5.        Dampers shall be as specified.

6.        Damper actuators shall be furnished and installed by the air temperature control contractor

Part 3 - Execution

3.3      Installation of Air Handling Units

A.       General:  Install  air handling units where indicated on the contract drawings, in accordance with the equipment manufacturer’s published installation instructions.

B.       Access:  Provide access space around the air handling units for service as indicated on the drawings, but not less than that recommended by the manufacturer.

C.      Support:  Install floor-mounted air handling units on 4” high concrete housekeeping pad, 4” larger on each side than unit base.

D.      Field Adjustments:  Adjust fan vibration isolators in accordance with manufacturer’s instructions. 

E.       Electrical Wiring:  Install electrical devices furnished by manufacturer, if any,  but not specified to be factory mounted.  Verify that electrical wiring installation is in accordance with manufacturer’s submittal and installation requirements of Division 16 sections.

F.       Piping Connections:  Provide piping, valves, accessories, gauges, supports, and flex connections as indicated on the contract drawings.  Locate freezestats and trap drain-pan connections according to manufacturer’s recommendations.

G.      Duct Connections:  Provide ductwork, accessories, and flex connections as indicated on the drawings.

3.2      Testing

A.       General:  Upon completion of air handling unit installation, start-up and operate equipment to demonstrate capability and compliance with contract document requirements.  Field correct any deficiencies and retest to demonstrate compliance.

3.3      Extra Stock

A.       Filters:  Provide one extra set of filters for each air handling unit.  Install new filters at completion of air handling system work, and prior to testing, adjusting and balancing work.  Do not operate fans unless filters are in place.

B.       Belts:  Provide one spare set of belts for each belt-driven air handling unit.  Deliver spare belts to the Contracting Officer’s representative and mark with air handling unit’s number.