J.1 - AHU Design Giudelines.pdf

AHU (Air Handling Unit) Design Guidelines

PART 1 – GENERAL

I. DESCRIPTION:

A. This standard covers the design, performance, fabrication, testing, cleaning and packaging, shipping, installation and final assembly of custom built-up air handling unit.

B. The details outlined and component manufacturers named in this specification are not absolute. However, any deviations from this standard must be specifically identified with potential cost savings to the customer and explanations of how the deviation creates a product that meets or exceeds the design intent of this standard.

C. This standard is to be used for labs and other critical environments and/or the expected life of the equipment exceeds 20-25 years (manufacturing areas).

II. QUALITY ASSURANCE

A. All equipment or components of this specification section shall meet or exceed the requirements and quality of the items herein specified or as denoted on the drawings and schedule.

B. Equipment furnished under this specification shall be in accordance with the following industry, association and government codes and standards, as applicable to their design, fabrication, assembly and testing.

1. AMCA 99 Standards

2. ARI 430 Central Station Air Handling Units

3. NFPA 70 National Electric Code

4. NFPA 90A Standard for the Installation of Air Conditioning and Ventilating System

5. NFPA 90B Standard for the Installation of Warm Air Heating and Air Conditioning Systems

C. Fans shall be rated in accordance with the following Standards:

1. AMCA Standard 210 for performance

2. AMCA Standard 301 for sound and shall bear the AMCA seal.

D. Motors shall meet requirements of NEMA, IEEE, ANSI, and NEC standard.

E. Coils shall be rated in accordance with ARI Standard 410 and bear the ARI seal.

F. Equipment within unit shall be UL listed where applicable.

III. SUBMITTALS:

A. QUOTATION: Provide the following detailed information on the equipment proposed. Unit manufacturer shall itemize all deviations from the specified requirements. If not so indicated, unit manufacturer will be required to furnish at no cost to the owner:

1. Information requested in the RFQ, including equipment data sheets, schedules and sketches.

2. Equipment drawings showing overall unit dimensions, and individual components and section dimensions, weights (shipping & operating), capacities, ratings, fan performance, overall configuration, major component locations, access door locations, duct connection sizes and locations, and shipping split locations.

3. Materials of construction for housing and major components.

4. Cross section details of typical wall, floor and roof construction

B. AFTER PLACEMENT OF ORDER: Make submittals in accordance with requirements of conditions of purchase. Submittals shall show Buyer’s purchase order number, equipment number and project number. Information shall include, as applicable, but not be limited to the following:

1. Information submitted with quotation, revised and expanded as required; including airborne and transmitted sound power levels by octave band for unit.

2. Fan manufacturer and performance curves with the operating points clearly indicated. Motor sizes and types. Submit fan curves with specified operating point clearly plotted.

3. Detail coil selections with sizes, rows, fin spacing, face velocity, air & fluid temperatures, flow rates, air & fluid pressure drops, and connection sizes. Submit psychometric chart for each cooling coil with design points and final operating point clearly noted.

4. Shop Drawings - Piping connections, sizes and locations

5. Shop Drawings - (If applicable) Electrical data, wiring diagrams, and accessory panel layouts.

Clearly differentiate between portions of wiring that are factory-installed and portions to be field-installed. Also include point to point wiring diagrams

6. Shop drawings – construction details including methods of fastening panels, assembling sections, thermal and galvanic break techniques, and materials of construction/

7. (If applicable) Factory testing procedures for review and acceptance.

8. Door and window sizes and elevations

9. Controls - Shop Drawings:

a) System wiring diagrams with sequence of operation for each system as specified.

b) Submit manufacturer's product information on all hardware items along with descriptive literature for all software programs to show compliance with specifications.

For complete detail of Controls requirements see University of Rochester Design Standards, section 15975, Direct Digital Control Systems.

C. AFTER RECEIPT OF APPROVED DRAWINGS: Submit manuals with detailed description of installation, operation, and maintenance, including the following:

1. Written recommendations for field storage, both indoors and outdoors.

2. Installation requirements including assembly instructions, lifting requirements and adjustments.

3. Manufacturer’s literature describing each piece of equipment including operation instructions with step-by-step preparation of starting, shutdown, and draining and maintenance instructions including lubrication.

4. Detailed commissioning procedures.

D. PRIOR TO SHIPMENT: Submit the following detailed information prior to shipment where these tests have been requested during the bidding process:

1. Fan/Motor assembly vibration test results.

2. Air handler casing leakage test results

3. Fan performance test result.

4. Sound power levels at the inlet and outlet test results.

5. Panel deflection test results.

IV. PRODUCT CLEANING, DELIVERY, STORAGE, AND HANDLING:

A. All equipment to be delivered to the job site suitably packaged and protected for overland trucking. In general, units will be delivered in one piece unless otherwise indicated. Where building constraints, unit size or trucking limitations require that unit ship in more than one piece, the manufacturer shall indicate split points on shop drawings.

B. Thoroughly clean equipment, components and subassemblies of water, dirt, debris, weld splatter, grease, oil and other foreign matter prior to shipment.

C. Unit to be prepped and completely sealed for protection during shipment.

1. Seal all openings in unit casings with gasketed, thin gauge sheet metal closure sheets.

2. Seal closures, caps and plugs dust-tight and moisture-tight.

3. Protect pipe flanges with plywood coverings; protect pipe threads with plastic end caps or plugs.

4. Protect machined surfaces with suitable, easily removable rust preventive.

5. Provide full charge of proper lubricant for grease lubricated bearings.

6. Provide desiccant bags or vapor phase inhibitors where required to keep components dry.

D. Ship all air handlers with complete protection from rain and dirt. Air handlers shipped on open trailers shall be protected with a minimum of two (2) layers of heavy mill shrink wrap plastic.

E. Units delivered with scratched, dented, or dirty surfaces or damage of any type shall be restored to “as new” condition as directed by the Architect/Engineer/Owner at no cost to Owner.

F. If equipment is to be stored before use, shipping protection provided by the unit manufacturer shall remain on the unit until the unit is installed. Manufacturer shall submit written recommendations for field storage.

G. Provide non-corrosive nameplate permanently attached to the equipment containing the following information:

1. Manufacturer’s project/serial number

2. Plant name and location

3. Customer equipment number

4. Date of manufacture

H. Provide lock down equipment for all vibration isolation during transport and handling

1. WARRANTY:

2. All equipment, materials, and workmanship shall be warranted for (18) months from official turn over.

Marlo Air handlers will be provided with a (3) year warranty from the date of shipment. During the warranty period, the manufacturer shall repair or replace, at no additional cost to the Owner, any equipment, material, or workmanship in which defects may develop.

3. Warranty is for parts only; labor to remove or reinstall parts is the responsibility of others.

4. Unit casing, structural base and roof (if outside unit) shall be warranted against corrosion or failure under normal operating conditions for a period of forty (40) years from the date of unit delivery.

PART 2 – UNIT CONSTRUCTION

I. MANUFACTURERS:

A. Provide air handling units as manufactured by: Air Enterprises, Ingenia, Marlo or Buffalo Air Handling.

B. Alternate pricing based on pre-approved manufacturers will be considered if the following performance requirements and construction techniques are adhered to in all respects. Any substitutions shall be approved by the Architect/Engineer/Owner in writing ten (30) days prior to bid.

C. The unit manufacturer shall have been manufacturing custom built-up air handling units for a minimum of 10 years and provide references if requested.

D. Air handlers that are field assembles (i.e. breakdown units) are to be Ingenia only.

II. CUSTOM BUILT-UP AIR HANDLING UNITS GENERAL:

A. Custom built-up units shall be of the configuration, capacity and style as indicated on the drawings and Equipment Schedule and as specified herein. Through properly designed access; ease of maintenance, removability of components, and unit serviceability shall be assured.

B. Classification as designated by the unit manufacturer or minimum requirement selected below:

Total Static Pressure Class

1. Up to 3.75” WC I

2. Up to 6.75” WC II

3. Up to 12.75” WC III

C. The units shall be constructed for (select) indoor / outdoor installation. (If outdoor chosen) Outdoor units to be provided with weatherproofing (roofing, guttering, etc.) as defined herein. All outdoor units shall be stainless steel exterior.

D. The units shall consist of: (develop appropriate listing) intake sections for return and outside air, mixing section with dampers for outside air, return air and exhaust air, pre- filter section, final filter section, heating coil section, cooling coil section, humidifier section, supply and return fan sections, diffuser section, and discharge section.

E. Units shall be provided with a complete LED NEMA 4X lighting system with timer, switches and receptacles, damper operators furnished and installed on all dampers, and motor wiring to safety disconnect switches. LED fixtures shall be equivalent to RAB Lighting SHARK4-50W/D10. Provide outdoor LED fixtures at vestibule entrances. Fixtures to be controlled by photocell.

F. As a general rule, the unit shall employ aluminum or stainless-steel materials (panels, bases, supports and safing) to maximize cleanliness of the conditioned air, facilitate and simplify maintenance and ensure longevity of the unit by eliminating rust potential.

G. Provide safing between internal components and unit casing to prevent air bypass. Safing material shall match unit interior. All seams or voids between safing, components and unit casing shall be caulked and sealed airtight.

H. Provide hygienic unit design with interior suitable for washing down without any vapor or water transfer into the wall or base cavities. Unit insulation must be closed cell foam. This requirement is due to the incidence of mold growth with fiberglass or open cell foam insulation when it gets wet.

I. The unit is to be shipped factory assembled in one complete section, when possible. If necessary to ship the unit in sections, due to rigging or shipping constraints, the unit is to be designed to minimize the number of sections. The unit manufacturer shall field erect the units in place at the jobsite.

J. The custom unit must fit and accommodate all constraints and still enable access to all components for maintenance and cleaning.

III. UNIT BASE:

A. The unit shall be constructed on an all-aluminum or 304 stainless steel structural base for outdoor applications. The base shall be designed to distribute loads properly to a suitable mounting surface and be braced to support internal components without sagging, pulsating or oil canning. Sheet metal formed bases are not acceptable.

B. The base floor shall be minimum 3/16” thick aluminum or 304 stainless steel plate welded at all joints and to structural members. Floor material shall have safety-tread surface in areas where people will be walking. The base floor shall be designed for a minimum live load of 150 pounds per square foot throughout the unit. The base floor is to be supported with adequate stiffening members to prevent oil canning. Caulking, gaskets and mechanical fasteners to guarantee seals and water tightness of joints will not be acceptable.

C. The perimeter support members shall be properly sized to support all major components and the housing during rigging, handling and operation of the unit.

D. The underneath side of the base pan and base perimeter shall be insulated with injected or sprayed closed cell foam of proper R-Value to prevent any condensation beneath the unit. Fiberglass batt insulation is not acceptable. Supplier shall demonstrate through thermal modeling or actual testing that no condensation will occur at the specified ambient temperatures and humidity where the AHU will be located.

E. Each section of the unit base shall contain a minimum 2” NPT drain to facilitate system wash down, maintenance and/or condensate removal. Areas in the base where potential standing water cannot be removed through drains or weep holes are not acceptable. Clean out drains shall be provided with removable caps of non-corrosive material. A 2” high lip welded bathtub style floor (though not required), is highly desirable. Any drainpipes in the Unit Base needs to be pitched a minimum of ¼” per foot. All unit drain piping shall be schedule 40 stainless-steel.

F. All equipment within air handling unit shall be provided with a minimum 6" high base to raise equipment off unit floor for housekeeping. These standoffs need to be welded to the base assembly. Equipment mounted directly on unit floor is unacceptable.

G. Supply air openings to be framed with 2” high water dam continuously welded to the pan to allow proper duct connections and to prevent moisture from entering the openings. Framed openings shall be provided with removable aluminum, or 304 stainless steel grating designed and fabricated for a live load of 100 pounds per square foot. Galvanized or painted steel grating will not be accepted.

H. All unit base service openings shall be framed with a minimum 2” high water dam continuously welded to the floor. All pipe and electric conduit chases with openings to building or elements shall be covered with thin gage aluminum or 304 stainless-steel. Penetrations by contractors should be minimized. If required, they shall be sealed by the respective contractor.

I. Fastening to floor plate or joining of unit sections to be accomplished by bolting through gasketed joints above the floor line or continuously welding. Fasteners which penetrate base floor plate are not acceptable.

J. Unit to be provided with properly located permanent lifting plates or removable lifting lugs for each section to adequately allow rigging of the unit sections in place.

K. Unit Base will be provided with mounting holes to secure it to the floor or structural steel to prevent movement created by seismic conditions. Base plates and bolt patterns shall be provided in such a manner that the forces are evenly distributed over the base of the unit.

IV. CABINET

A. The unit casing construction is one of the most critical factors for a long-life trouble fee air handler.

Construction details vary among manufacturers of custom units. This section documents the performance of the unit casing with a few specifications that prevent problems encountered in the past.

B. Complete no metal through construction (thermal break) in all locations. This no metal through construction intent is to prevent condensation and subsequent mold growth from occurring. The thermal break usually consists of a minimum 1/2" structural non-metallic bridge. Adhesive tapes, caulking or gaskets do not constitute an acceptable thermal break.

C. Unit Casing shall be built up from the unit base with load bearing panels. Panels should be capable of forming the enclosure without additional structural members. Structural members are acceptable in some instances. Panels shall be joined together with independent joining member and fastened with closed end stainless steel fasteners. Plated fasteners will not be accepted.

D. Each panel shall contain an integral frame or be properly supported by a structural framing system.

Panel shall have continuous tight seal at the interior and exterior skins completely encapsulating the insulation. The intent is to guarantee structural integrity and no moisture getting inside the panel.

E. The panel thickness should be dictated by the R-value required to prevent any exterior condensation and meet the structural stiffness and noise specification. All insulation to be closed cell injected foam. At a minimum, outdoor units should have R-value of 18. Indoor units require an R-value of 13 or greater.

Noise and stiffness requirements along with Federal energy code may dictate thicker walls with higher R-values. Under normal operating design conditions, there shall be no condensation on the unit exterior at the following ambient conditions:

Indoor Units 105°F DB, 80°WB Outdoor Units 115°F DB, 80 °WB

F. Thickness of the panel skin, core density, rib structural frame spacing shall be regulated to eliminate panel pulsation and restrict the maximum deflection to L/250 of any span at design load of 1-1/2 times the design positive or negative pressure plus snow and wind loading. The maximum deflection of roof and floor shall be L/360 at design loading. Deflection is worst case at the center of the panel

G. Casing system shall be guaranteed to assure the owner that system capacity, performance, and cleanliness standards specified are not compromised. Leakage to be guaranteed at no more than (1%) of the design volume at 1-1/2 times the design operating pressure or 30 CFM, whichever is greater.

Sections of casing need to be pressure tested in pressure mode (negative or positive) which they will normally operate. For example, the suction side of the fan should be pressure tested with negative pressure differential. The units shall be tested prior to shipping. An owner’s representative shall witness the test. Manufacturer to provide for expenses of one owner’s representative to witness the test with a minimum two-week notice.

H. All casing walls shall be of panel construction, including but not limited to the fan discharge walls, mixing section walls and divider wall to the access corridor.

I. Any equipment flashing, internal partitions or other attachments to the casing shall be made in such a way as to ensure a permanent leak-tight connection. Attachments that are bolted, screwed, or welded to or through the casing creating air bypass, air leakage or rust propagation areas are not acceptable. Air handlers shall have no through metal constriction.

J. All ductwork penetrations through unit enclosure shall be provided with framed openings of size and arrangement as indicated on drawing. Openings to be provided with flanged duct connections of same material as casing interior extending a minimum of 4” from surface of unit casing.

K. Pipe and conduit penetrations through the unit casings shall be provided by the unit manufacturer and be properly sealed prior to leaving the factory. Penetrations sealed by simply caulking around extension are not acceptable.

L. Seismic requirements – when earthquake loads are applicable, equipment will be designed and installed for the seismic forces in accordance with the Building Code of Washington DC and be certified and appropriately labeled.

M. Stacked units shall consider the weights of all upper units in calculating structural loading of lower units in addition to catwalks, platforms and ladders.

N. Provide minimum 18” wide access doors for access to all internal components. Access doors shall be installed to open against the greatest pressure relative to air pressure on each side of access door.

Where this is not feasible, an interlocking mechanism is required to prevent damage or injury.

1. Access doors shall be of the same construction as panels described above. This includes the thermal break requirements.

2. The access doors shall incorporate two continuous separate gasket seals around the entire periphery of the door. Gasket material shall be UV-resistant, closed cell neoprene; gaskets shall be attached by adhesive or mechanically held in place. Single gasket seals will not be accepted.

Door gasket should be seamed together at each corner to prevent leakage through the door.

3. Each access door shall contain a thermo pane safety glass window (min. 10” square).

4. If fan blades are exposed during operation an OSHA approved interlock switch is required on the door which de-energizes the fan before entry. Provide door interlock switch(s) to disable UV lighting system. Fan guarding is also acceptable.

5. Provide 1” dia. test ports with screwed caps on casing upstream and downstream of all coils and filters for pressure and temperature measurement.

6. Each access door shall be mounted with a corrosion-resistant hinge and shall have a least two

(2) non-corrosive handles operable from either side. Handles need to be at an acceptable height when standing outside the unit. Exterior AHU’s shall utilize stainless steel door hardware.

O. Removable access panels shall be provided as appropriate for service and maintenance. They need to be sized appropriately for the component that is being replaced or repaired. Access panels shall be of the same construction as panels described above. Removable access panels shall be designed and constructed such that removal and replacement may be accomplished without disturbing adjacent panels. Airtight integrity must be maintained.

P. For large internal components such as fans and motors, install structural I-beam over center of gravity of component to be removed, so hoist mechanism can be used to safely lift and remove the component from the unit casing.

Q. Materials

Interior units – Solid aluminum or stainless-steel exterior panels. Interior panels, G90 galvanized panels with factory applied anti-microbial coating or polished 304 stainless steel interior panels can be utilized in lieu of the antimicrobial finish.

Exterior – Outside Units Stainless Steel exterior panels. Aluminum or stainless steel with factory applied anti-microbial coating on interior panels. Polished 304 stainless steel interior panels can be utilized in lieu of the antimicrobial finish.

V. EXTERIOR | EXTERIOR & INTERIOR FINISH

A. The interior surfaces of the air handler shall be powder coated. Interior surfaces can be 304 polished stainless steel.

B. The Interior finish shall be WHITE ANTI-MICROBIAL powder coated or polished 304 stainless-steel.

C. The powder coating process shall include; Pre-washing; Rinsing; Re-washing; Rinsing cycle l; Rinsing cycle ll; Oven dry @ 400 deg F; Electrostatic paint application (powder format); Baked finish @ 400 deg F.

D. Paint shall be applied in an electrostatic powder coating system. The electrostatic spraying shall be accomplished by applying an electrical charge to the dry powder particles while the component to be painted is electrically grounded. The charged powder and grounded work piece create an electrostatic field that pulls the paint particles to the work piece. The coating deposited on the work piece retains its charge, which holds the powder to the work piece. The coated work piece is placed in a curing oven, where the paint particles are melted onto the surface and the charge is dissipated. The paint system shall be environmentally friendly, therefore eliminating the use of volatile organic compounds (VOC’s), hazardous air pollutants (HAP’s) and solvents.

Individual panels must be painted prior to final assembly to ensure painting of all sheared metal edges and concealed surfaces. The paint coating shall resist 1000 hours to the standard ASTM-B117 scratch salt spray test and resist 2000 | 4000 hours to the standard ASTM-B117 exposure salt spray test.

VI. ROOF SYSTEM (use for outdoor units)

A. Unit roofs for outdoor units are to be sloped a minimum of 1/4” per foot to assure positive run-off.

Roof to peak in center and drain off to both sides / on door side and drain away from door side.

B. The roof system shall be constructed of 304 stainless-steel only. The roof panels shall be interlocked standing seam construction. The use of a membrane roofing system is prohibited.

C. Unit shall be provided with a non-corrosive rain gutter system with downspouts to guide unit roof water run-off to the building roof. Units incorporating roof systems without controlled water run-off accommodations are not acceptable.

VII. OUTSIDE AIR SECTION (For outdoor units or units in mechanical rooms that don’t have common air intake plenum)

A. Outside air shall be admitted and exhaust air shall be discharged through stormproof stainless-steel louvers. Louvers shall be designed to prevent the penetration of wind driven rain. Weather hood exterior and construction to match the finish of the unit casing.

B. Louver shall have AMCA certified air performance and water penetration ratings. (AMCA

500-L Wind Driven Rain Test).

C. Bird screen: stainless steel mesh.

D. Outside air intake shall be sized for a maximum of 350 fpm to minimize snow intake. Exhaust air discharge shall be sized for a maximum of 750 fpm.

VIII. CONTROL DAMPERS

A. Dampers shall be low leakage type with flexible seals for frame and blades.

B. Dampers shall be sized appropriately without blanking off free areas

C. Damper capable of withstanding specified” WC differential pressure at specified fpm approach velocity. (HVAC engineering firm to specify).

D. Damper should be maintenance free, other than yearly wipe down. Damper should have concealed linkages. No lubrication should be needed for bearings or linkages. The use of plastic blade bearings is prohibited.

E. Damper frames shall be made of extruded aluminum. Damper blades shall be extruded aluminum airfoil shape to withstand high velocities and static pressures.

F. Outside air damper banks can be handled in one of two ways. First, incorporate a two- position minimum outside air and an independent modulating outside air damper. Second, minimum outside air provided by controlling outside air damper bank to a minimum position. Healthcare specific: Outside air should have flow station as a means of demonstrating code compliance for outside air.

G. Damper actuators to be mounted by unit manufacturer. Actuators for dampers with modulating control to be provided with position feedback (4-20 ma).

H. Damper should be appropriate for the application. Outside air damper should be designed to prevent freeze-up and reduce condensation. Maintenance free oiled bronze bearings preferred.

I. Acceptable dampers: Low Leakage TAMCO or Ruskin model appropriate for the application.

IX. MIXING SECTION (For Mixed Air AHU Only)

A. Complete with framed openings with low-leakage outside and return air dampers. Dampers shall be as specified below and shall be furnished and installed by the unit manufacturer.

B. Mixing section shall be designed for controlled mixing in that the proximity, relation, and air velocity for each respective damper shall be such that volume swings and stratification will be eliminated.

C. Outside air damper banks can be handled in one of two ways. First, incorporate a two- position minimum outside air damper and a second independent modulating outside air damper. Second option, use of one OA damper. Minimum outside air provided by controlling outside air damper bank to a minimum position. Outside air should have flow station as a means of demonstrating compliance for outside air intake.

D. Mixing should eliminate possibility of air stratification where cold outside air can freeze chilled water coil, or an air blender needs to be incorporated into the design.

X. DRAIN PANS

A. Condensate drain pan are Indoor Air Quality compliant complying with ASHRAE Standard

62.1-2007 Ventilation for Acceptable Indoor Air Quality.

B. Fabricated from minimum thickness 16-gauge 304 stainless steel

C. Absolutely no standing water allowed to accumulate in the pan.

D. Minimum 1 1/2 “drain connection at lowest point in the pan.

E. Coils to be mounted on supports above drain pan. Coil supports cannot prevent water drainage.

F. Air cannot bypass around coil through drain pan.

XI. SUPPLY & RETURN FAN SECTIONS:

A. General Guidelines are as follows:

1. Provide fans, motors and drives of number, size and capacity as required and appropriate for the application. Design should incorporate the optimal number of fans to maximize efficiency and meet the agreed upon redundancy specification (n+1). Selecting the least number of fans that meet the redundancy requirements will normally produce the most efficient system design.

2. Reference Standard 233416 – Centrifugal Fans for general info on construction and performance.

3. System effects must be carefully evaluated to ensure no excessive efficiency losses.

4. Direct drive fans are preferred in most instances to eliminate mechanical belt losses and maintenance required by units which have belts and sheaves. Utilize belt driven fans only with the concurrence of owner.

5. All motors shall include isolated bearings or shaft grounding to prevent premature bearing failure due to VFD induced electrical damage.

6. Performance: Performance ratings shall conform to AMCA standard 205 (fan efficiency grade), 211 (air performance) and 311 (sound performance). Fans shall be tested in accordance with ANSI/AMCA Standard 210 (air performance) and 300 (sound performance) in an AMCA accredited laboratory. Fans shall be licensed to bear the AMCA certified ratings seal for both sound and air and fan efficiency grade (FEG).

B. (Housed Fans)

Centrifugal fan sections shall be complete with DWDI (double width double inlet), arrangement 3 or 7 preferred but others considered for optimizing the design. High efficiency backward inclined airfoil blade design. Reference Standard 233416 Centrifugal Fan for specifics on the construction and performance in addition to the following:

1. Fan housing shall be heavy gauge construction with spun inlet cones. Housings shall be suitably braced to prevent vibration or pulsation. Scroll housing shall be connected to side plates with a high-quality airtight seal; seam shall be continuously welded as required for application.

Bearing supports shall be rigid and shall provide a firm foundation for the shaft and bearings. Bearings supported from the fan housing will not be acceptable.

2. Bearings are to be heavy duty, grease lubricated, anti-friction, self-aligning, and pillow block type and selected for minimum average bearing life (AFBMA L-10) of 200,000 hours at the maximum class RPM. All bearings shall be equipped with Zerk fittings and lubrication lines extended to accessible location on fan housing for easy access for lubrication.

3. Fan shall be provided with heavy gauge wire inlet screens, housing access door, and scroll drain as required. In the event inlet vanes are provided, fan will not require inlet screens.

4. Fan shall be cleaned, prime coated and provided with two coats of epoxy final coat.

5. Each fan shall be testing run at their operating speed or at the maximum RPM for the particular.

6. (Belt Driven Arr. 3 only) Motor shall be mounted on an adjustable motor base affixed to the fan vibration base. The motor base shall control belt tension in order to minimize belt servicing and extend belt life. The motor base shall be permanently aligned type so belts can be changed without having to realign the motor and V-belt drive. The motor base shall be mounted parallel to belt pull for maximum bearing life

7. (Belt Driven Arr. 3 only) The V-belt drive shall be the constant speed type provided with a minimum of two (2) drive belts. Drives with two (2) belts shall have a minimum service factor of 2.0; all other drives shall have a service factor of 1.5

8. (Belt Driven Arr. 3 only) V-belt drive shall be enclosed in a perforated metal belt guard. The belt guard is to be a two-piece design split along shaft centerlines; fastened with two quick disconnect clasps so that access to the belts can be made without the use of any tools. Designs resulting in loose hardware will not be accepted. Belt guard shall have framed holes at the fan & motor shaft with cover plates to allow for tachometer measurement.

9. The entire fan assembly shall be provided with a minimum of 18” clearance on all unattached sides for proper service access. Fan inlets to be provided with a minimum clearance distance equal to 75% of the wheel diameter.

10. The unit manufacturer shall provide flexible connection between fan and fan wall if required to meet vibration or noise specifications. Fan assembly shall be provided with thrust arrestors as required to prevent damage to the flex connection. Flex connection material shall be flame retardant fabric suitable for intended use meeting the requirements of NFPA 90A.

11. Acceptable fan manufacturers: Twin City Fan (preferred), Greenheck, Cook, New York Blower

C. (Plenum/Plug Fan) Fan sections shall be complete with SWSI, arrangement 4, minimum of 12 high efficiency air foil shaped aluminum extruded blades and direct drive. All wheels shall be continuously welded around all edges.

1. Fan unit shall be formed by welding heavy gauge steel inlet plate with spun inlet cones to steel angle frame. A square formed lip shall surround the unit, suitable for attachment of flex connector.

2. Fan wheels shall be non-overloading, airfoil type. Impellers shall be statically and dynamically balanced to a level of G6.3 (per ANSI 2-19) or better. Hubs shall be straight bored, keyed and set screwed to the shaft.

3. Bearings are to be heavy duty, grease lubricated, anti-friction, self-aligning, pillow block type and selected for minimum average bearing life (AFBMA L-10) in excess of 200,000 hours at the maximum class RPM. All bearings shall be equipped with Zerk fittings and lubrication lines extended to accessible location on fan housing for easy access for lubrication.

4. Fan shall be provided with wire mesh protective wheel enclosure and heavy gauge wire inlet screen. In the event inlet vanes are provided, fan will not require inlet screens.

5. Fan shall be cleaned, prime coated and provided with two coats of epoxy final coat.

6. Acceptable fan manufacturers: Twin City Fan (preferred), Greenheck, Cook, New York Blower.

D. (Fan Array)

Special case application of plenum fan in which multiple fans, motors, cabinetry and controls are integrated together into an array to deliver uniform, quiet optimized air flow.

1. Multiple, direct driven arrangement 4 plenum fans constructed as Class II or Class III per AMCA requirements. Fan wheel has a minimum of 12 blades made from extruded aluminum as hollow airfoil shape and welded to the center and wheel side plates. The fan inlet cone is made from spun aluminum.

2. Each fan cube shall be individually wired to a control panel with single VFD or multiple VFDs dependent upon the agreed upon controls strategy and redundancy requirements.

3. High voltage and control wiring needs to be properly isolated to prevent induced voltages from occurring on other fans.

4. Each fan to be equipped with a metal grating fan outlet guard.

5. Each fan/motor assembly shall be independently removable through a 30” wide access door. A motor removal rail shall span the full internal width of the unit. Also need to include a blank-off panel to isolate the inlet side of the fan/motor assembly that is being removed. Mot

6. (Option) Each fan/motor cube will be provided with an individual back-draft damper.

7. (Option) All or one fan assembly shall be supplied with a complete flow measuring system.

E. Motors shall be 1750 RPM, 460V/3ph/60Hz as per the following:

1. Motor shall be premium efficient totally enclosed fan cooled (TEFC) rated for severe duty or higher.

2. Motor shall be of HP as listed on schedule and be selected for a minimum of 15-20% over calculated BHP. The motor service factor shall be a minimum of 1.15.

(Substitute for arr. 4 direct drive) Motor shall be of HP listed on schedule; selected to provide adequate torque throughout entire range of fan operation and not exceed nameplate HP when fan operates at synchronous motor speed.

3. Motor shall be designed for continuous duty operation, NEMA Design B with class F insulation.

4. The motor shall be suitable for operating with variable frequency drives without undue noise, vibration or deterioration of reliability and life.

5. Motors shall be “Inverter Duty Rated” per NEMA Std. MG1 part 31.4.4.2 and labeled as such.

6. Variable frequency PWM driven motors shall include a circumferential, conductive microfiber shaft grounding ring or equivalent shall be installed on the AC motor to discharge shaft currents to ground.

7. Provide stainless steel nameplate indicating the following:

a) NEMA efficiency index nominal efficient (MB1-12.53BO).

b) AFBMA bearing numbers.

c) Lubrication instructions.

8. Acceptable motor manufactures: Baldor, RPM XE eXtreme Efficient Motors. Utilize Marathon Three Phase SyMax Permanent Magnet Motors for 5 Horsepower or below.

9. The use of EC motors is prohibited.

XII. AIR FLOW MEASUREMENT

A. Provide airflow measurement device and transmitters for the purpose of continuously monitoring unit airflow volume. This includes outside air flow and total air flow as required and building codes. For building automation, return air and exhaust air flows also need to be monitored.

B. Airflow flow measurements can be accomplished in a variety of ways. One acceptable method includes a piezometric flow ring incorporated into the inlet of a fan. Other methods include flow station.

Acceptable manufacturers Ebtron or Vortek. Provide Ebtron Gold series for duct mount AFMS.

XIII. FILTER SECTIONS:

A. Provide all pre-filters and final filters of number, size and capacity as required for air handling system indicated on drawings and as stated in these specifications. Filters to be selected for a maximum face velocity of 500 fpm.

B. Filters shall have nominal rating of 500 fpm. Each cell shall be 24" x 24", or 12” x 24”. Media shall be approved and listed as Underwriters Laboratories Class 2 when tested according to UL Standard 900 and as described below:

1. Pre-filters: 2" thick MERV 8 efficiency minimum. Contact facilities for recommended pre-filter.

2. Final Filters: 12” rigid pleated V-type, MERV 13 minimum. Contact GPO for recommended final filter depending on application.

3. HEPA Filters: 99.97% (when tested with 0.3 micron thermally generated particulates) high-capacity HEPA filters tested and certified. Contact facilities for recommended model HEPA filter.

C. Filters shall be upstream removable (face mounted). Side access is not acceptable. Pre- filter sections shall be complete with holding frames capable of holding pre-filters with high efficiency filters. Pre-filters shall be capable of being removed and installed without affecting seal of the high efficiency filter.

D. Filter frames upstream of cooling coils or humidifiers can be galvanized steel or aluminum construction. Stainless steel construction required for locations downstream of cooling coils or humidifiers. No gaskets needed on filter frames as filters are purchased with gaskets. Filter holding frames shall be installed and individually sealed to prevent leakage around frames. Filter banks shall be reinforced with vertical stiffeners to assure rigidity for up to 3.5-4” pressure differential. Unit manufacturer shall provide flashing between filter banks and unit casings to prevent air leakage or bypass around the frames. Installation techniques, sealing methods, and structural reinforcement eliminate unfiltered air bypass and assure system cleanliness based on filter efficiencies specified.

E. Unit manufacturer shall provide and install a Dwyer series 2000 magnehelic gauge complete with stainless steel static pressure tips and accessories for indicating the operating pressure drop of each filter bank. Indicating range of gauge shall be selected at two times the final resistance of the filter bank. Provide hose barbs to connect indicating transmitter to the control system.

F. (Optional) Unit manufacturer shall provide (2) sets of pre-filter media and (2) sets of final filter media, and (2) sets of HEPA filter media with the unit for installation.

G. Acceptable filter frame manufacturers are as follows: Pre-filter – Camfil Farr Magna Frame or equivalent Final filter – Opti frame or approved equal.

XIV. HEPA/ULPA FILTERS

A. The final filters shall be HEPA type. Only approved HEPA framing system shall be used. Air filters shall be HEPA grade high-capacity air Filters (24 x 24 rated for 2000 CFM at 1.4” w.g.) with waterproof micro glass fiber media, tapered corrugated aluminum separators, urethane sealant, a galvannealed 16-gauge steel enclosing frame, and neoprene sealing gasket. Filter media shall be one continuous pleating of micro glass fiber media. Pleats shall be uniformly separated by tapered corrugated aluminum separators incorporating a hemmed edge to prevent damage to the media. The media pack shall be potted into the enclosing frame through the use of a urethane sealant. The enclosing frame of galvannealed 16-gauge steel, shall be bonded to the media pack and form a rugged and durable enclosure. The filter shall be assembled without the use of fasteners to assure no frame penetrations. Overall dimensional tolerance shall be correct within - 1/8”, +0”, and square within 1/8”. A poured-in-place seamless sealing gasket shall be included on the downstream side of the enclosing frame to form a positive seal upon installation.

B. The filter shall have a tested efficiency of 99.97% | 99.99%| 99.999% when evaluated under the guidance of IEST TEST A Recommended Practice RP-CC001. The Initial resistance to airflow shall not exceed 1.4” w.g. at rated capacity. Filter shall be rated by Underwriters Laboratories as UL Class 1. The filter shall be capable of withstanding 10” w.g. without failure

C. of the media pack. The filter shall be labeled as to tested efficiency, rated/tested airflow, pressure drop and shall be serialized for identification.

D. Holding frames shall be HEPA FILTER FRAME PLUS constructed of 22-gauge galvanized steel | aluminum | stainless steel 304. Frames shall be bolted together, sealed with butyl membrane accompanied with swing bolt assemblies. Filters are to be punched and kept as one piece as much as possible to limit by-pass. Filter frames construction allows the use of membrane at the frame joints for the zero-air leakage. An appropriate number of swing bolts to match air filters shall also be included. Sizes shall be as noted on drawings or other supporting materials. Filter securing swing bolt assemblies, of the same construction as the frame, shall be offset to facilitate multiple filter installations. The assembly shall include appropriate swing bolts to match filter depth and equal-bearing clamps to allow uniform filter sealing. The sealing assembly shall create a scan capable filter to frame assembly seal.

E. The cartridges shall be disposable and shall consist of reinforced synthetic fibers mounted in a galvanized steel or aluminum frame system for outdoor units.

XV. ULTRAVIOLET LIGHTS

A. Independent Testing – All UV-C fixtures shall have been tested and labeled as UL Listed.

B. Fixtures – Fixtures shall be HVACR style high output (HO) types optimized for both heating and cooling temperatures of from 1-70 C, in air streams of 750 fpm. Fixtures shall be constructed of hospital grade (304) stainless steel and shall be capable of being mounted anywhere in the system and/or as shown on the plans. Each fixture shall be constructed with mounting holes, weep holes, and 6- ½” electrical knockouts, 3- at each end, to facilitate installation.

C. Power Supplies - Power supplies shall be completely waterproof and be of the high efficiency electronic type, matched to the lamp and designed to maximize UV-C photon production, lamp irradiance, energy efficiency and reliability. They shall be waterproof and UL Listed and labeled for use in airstreams of 1-70° C. They shall be capable of producing the specified output and organism destruction as specified under Intensity using no more than 10 Watts of power consumption for each square foot of treated, cross sectional plane.

D. Lamps – Lamp Watts shall be printed clearly on all lamps. Lamps shall be high output (HO), T5 diameter, rapid-start, medium bi-pin types that produce UV-C of 254 nm. Each lamp shall contain no more than 8 mg of mercury and shall be capable of operating in air temperatures of 1-70 C and velocities to 750 fpm. Useful lamp life shall be 9000 hours with no more than a 20% output loss at the end of lamp life when used continuously. They shall be constructed with UV-C resistant bases and shall not produce measurable ozone.

E. Irradiation - Lamps and fixtures are to be installed in sufficient quantity and in such a manner so as to provide an “equal” distribution of UV-C energy within the irradiated plenum. When installed, the UV-C energy shall be of the lowest possible reflected and shadowed losses.

F. Intensity - The minimal UV-C energy striking all surfaces shall at all times be sufficient to continuously destroy surface mold and bacteria as typically found in HVAC systems.

G. Installation – When used for surface irradiation, the fixture assembly shall be designed and installed such that the sum of the fixture row lengths shall be equal to a minimum of 90% of the coil surfaces width. Fixture rows shall be electrically terminated in accordance with both NEC and local codes. Fixtures shall be mounted to irradiate the intended surface(s) as well as all of the available line of sight airstream by proper placement and incident angle reflection.

H. Safety – UV-C system on/0ff switches shall be installed on the exterior of all UV-C plenums next to the plenum access door. Mechanical interlock switches shall be installed on all access panels and doors to the UV-C plenums to ensure that the UVC fixtures will be de- energized when any of these accesses are opened.

I. Acceptable manufacturers; Steril-Aire, UV Resources, or FRESH-AIRE UV.

XVI. HUMIDIFIERS – Pressurized Short Absorption Steam Distribution

A. Where specified, provide panel type, steam dispersion humidifier designed for short absorption distribution of size, arrangement, and capacity as required for air handling system indicated on drawings and as stated in these specifications. Humidifier manifold to be selected with maximum face velocity of [500] fpm.

B. Absorption distance shall not exceed 24” at desired conditions. Air handling manufacturer shall be responsible for proper absorption distance for steam between humidifier and downstream components. Vertical distribution tubes are preferred for efficient residual condensate removal.

C. Dispersion panel to be provided with stainless steel casings. Panel to be mounted on a stainless-steel support structure with stainless flashing between humidifier and casing walls to prevent air bypass. The dispersion tubes shall be constructed of 304 stainless-steel. The dispersion tube spacing shall be optimized to provide the best steam coverage and shortest absorption distance.

D. Steam supply and condensate return connections are to be extended and sealed through the casing wall. The condensate connections shall be a minimum of 18” above the unit base to allow for proper trapping; if required, condensate trap to be installed by AHU manufacturer internal to unit.

E. All humidifier sections shall have a stainless-steel drain pan that extends 24” longer than the absorption distance

F. Humidifier is to be provided with 4-20 ma electric operator, F&T traps as required and Y-type strainer for steam supply line.

G. Acceptable dispersion panel manufacturer: DriSteem or equivalent.

H. Provide electric steam generator per owner’s requirements. Supply reverse osmosis (RO) water to electric steam generator. Electric steam generator control system shall meet the requirements of GPO’s Integrated Automation Control Systems Specification.

XVII. EVAPORATIVE HUMIDIFICATION SYSTEM

MATERIALS AND COMPONENTS

Where specified, provide packaged humidifiers and ancillary equipment with manufacturer’s standard materials and components as indicated and published product information, designed and constructed by manufacturer, and as required for complete installation. Evaporative humidification system control system components shall meet the requirements GPO’s Integrated Automation Control System Specification.

XVIII. HIGH PRESSURE WATER ATOMIZATION TYPE HUMIDIFIER

1. General: Provide high pressure water atomization type humidifier including the following components:

a. Fog nozzles

b. Fog pump unit(s)

c. Water treatment equipment (using RO treated water).

d. Fog nozzle manifolds and main feed lines.

e. Droplet Filters and frames

f. Electrical panels and automatic control valves.

The system component sizes and capacities shall meet the specified load for humidification zones.

High pressure humidification system shall not use more than .003 kW/# of moisture generated.

2. Fog Nozzle Section:

a. Nozzle: 316 stainless steel construction with a 0.008” (0.2 mm) machined orifice.

b. Median droplet size to be between 10-40 microns with 95% of the droplets at 15 microns or less at 1,000 psig (69 bar) operating pressure.

c. The nozzle manifold to be constructed of ½” OD 316 stainless steel tubing with 0.035” wall thickness.

d. Nozzle saddles to be TIG welded to the manifold.

e. All connections between tubing to be 316 stainless steel double-ferrule compression fittings.

f. Nozzle section in AHU must be non-corrosive and include a stainless-steel drain pan that slope to the drain.

3. High pressure water pump units: Complete fog pump units shall include the following:

a. Oil or water lubricated ceramic plunger pumps with stainless steel heads:

Water lubricated axial piston pumps are not to be used due to noise…