CLEANROOM MAKEUP AIR HANDLING UNIT SPECIFICATION
1. Cleanroom Makeup Air Handling Units Testing and Standards
1.1. Unit shall be completely factory assembled and tested prior to shipment and shall be listed per UL 1995, as a complete assembly and shall be labeled as such. Fans shall be tested and rated in accordance with AMCA Standard 210 for performance and in accordance with ANSI standards of testing for sound power levels using the sound intensity method as referenced in AMCA standard 320 for sound. If the manufacturer cannot provide an ETL/UL sticker on the air handler, it will be the sole responsibility of the contractor to arrange for local ETL or UL approval and labeling.
1.2. The Unit Electrical Panel(s) shall be built in strict accordance to NEC Standards and shall bear an appropriate label certifying compliance with UL Standard 508A.
1.3. The air handling equipment manufacturer shall provide single source responsibility for all
components for the unit whether specifically manufactured by the unit manufacturer or obtained outside and installed in the equipment with the exception of consumable items such as filters, fan belts, etc., or as specifically warranted by the product manufacturer such as motors, VFD’s, etc.
1.4. The attached schedules, tables and specifications are to be used as the selection criteria for the
air handling equipment to include Air Flow Rates, External Static Pressures and Water Flow
Rates. The following are to be equaled or bettered: Coil Face Velocities and Filter Face Velocities. The following are to be met within 5% of specified values: internal air pressure drops using an AMCA leak testing machine with calibrated orifices, water pressure drops.
1.5. Additional Testing and Quality Assurance as explained in individual component / item sections in the following paragraphs of this specification.
2. Submittals:
2.1. Submit shop drawings with product data.
2.2. Shop drawings shall indicate assembly weights, unit dimensions, required clearances, construction details, and field connection details.
2.3. Product data shall indicate dimensions, weights, capacities, ratings, fan performance to include fan curves, motor electrical characteristics to include motor technical data sheets, coil capacities to include performance printouts with pressure drops (water & air), vibration isolation, filter data sheets to include pressure drops, gauges and finishes.
2.4. Clearly identify any variations from contract documents.
2.5. Provide space on cover document for contractor and architect/engineer review stamps.
2.6. Revise & resubmit submittals as required.
3. Operation and Maintenance Data:
3.1. Submit Installation, Start-up and Operation & Maintenance Data.
3.2. Include instructions for rigging, lifting, bearing lubrication, filter replacement, motor and drive replacement, and wiring diagram.
3.3. Include a recommended spare parts list customized to each unit complete with appropriate tag #, serial and / or part numbers along with a description to clearly identify the items.
4. Cabinet:
4.1. Casing Construction: Walls and roof to be (2”) (4”) “Double Wall” construction as indicated in the specification for each section of the unit. Cabinet is with a minimum 16-gauge A60 galvanized (Alum) (SS) solid outer panel and a minimum 20-gauge G90 galvanized, inner liner for double walls (solid, perforated…). Panels to be of standing seam construction with seams turned inward to provide a smooth flush exterior. Panels to be screwed (bolted) together on maximum 8” centers with minimum 5/16” zinc plated screws (bolts) sealed with a continuous bead of silicone caulking applied between the matching panel seams prior to assembly (sandwiched and sealed by the compression of the panels), and with a final bead following assembly on both the exterior and interior panel seams to produce an air tight unit. Wall to base skin and wall to roof panel seams shall be sealed with 1/2” x 1/8” Poron-Rubber strips and all exterior seams shall be continuously caulked to assure leak-proof integrity of the unit housing. AHU unit housing shall be constructed to prevent conditioned air bypass or mitigation through unit walls, roof and floor around any interior partition or component blank-off walls such as for filters, coils or fan bulkheads. At the discretion of the design engineer, the manufacturer may be required to perform casing leak testing for purposes of demonstrating that the unit casing leakage rate at 1.5 times the design maximum fan operating static pressure is less than .5% of design airflow. Such testing will be performed at the manufacturer’s facility. At the sole discretion of the design engineer, such testing shall be witnessed by an owner’s representative. A certified test report of such testing shall be included in the O&M Manuals provided at the time of shipment of the equipment.
4.2. Insulation: Panels to be insulated with 2” - 3-pound double density pre-molded rigid board fire-resistant with (matte face) (scrim-Kraft - PSK faced insulation. (Optional 1.5, 4.5, 6 pound density or other). Insulation to meet NFPA 90A, NFPA 90B and ASTM E 84 requirements for Flame Spread of 25 or less and Smoke Development of 50 or less. Insulation shall have a thermal conductivity K factor of .23 Btu/hr/Sq. ft/degree F @ 75 F mean and provide the following sound attenuation characteristics (per ASTM C 423 - Type “A” Mounting):
Octave bands 125 250 500 1k 2k 4k 8k
Absorption Coefficient .17 .80 1.16 1.15 1.11 1.10 1.05 (for 2” – 3#)
All cut edges of the board insulation shall be completely enclosed by the unit panels.
A finish bead of caulking will be applied over all foil to panel seams and/or inner liners
to main panel seams to completely encapsulate the insulation.
4.3. Interior liners: to be minimum 20-gauge G90 (304 SS or Alum) powder coated solid (perforated) metal throughout the unit for the walls and roof except in the cooling coil section, humidifier section and its immediate downstream plenum which will have solid 304 SS inner liners. A finish bead of caulking will be applied between the liner and the interior panel seams to completely seal the panel.
4.4. Roof panels: on units shall be flat with smooth exteriors the same as the side panels. All doors and louvers shall have a formed rain shield extending a minimum of 1” from the wall to direct water away from the door and louver openings.
4.5. Stiffeners of angle steel shall be supplied as required to maintain a casing deflection criteria of 1/100 at 1.5 times the working pressure.
5. Access Doors:
5.1. Access doors shall be (2.6”) double wall (thermal break) construction with (G-90 galvanized) (304 Stainless Steel) (Aluminum) exterior panels and (G-90 galvanized) (Aluminum) (304 Stainless Steel) interior panel. Door jam & frame shall be constructed of extruded aluminum with continuously welded corners for rigidity. Door panels shall be insulated with (2.6”) expandable urethane foam insulation completely encapsulated and sealed between the door panels and frame. Provide doors located and sized to allow for routine maintenance including motor replacement and filter replacement, electrical components and any other sections or components requiring access or maintenance.
5.2. Doors shall be provided with a minimum (2) dual acting heavy duty key locking composite latches through 48” high, (3) latches through 72” high. Latches shall be operable from both the interior and exterior of the unit. Door latches on doors into fan sections shall be provided with a hasp or other mechanism to facilitate locking of the doors. Door hinge shall be heavy duty Stainless Steel. Door shall be sealed with continuous hollow closed cell foam gasket.
5.3. Doors to be provided with double high performance closed cell replaceable neoprene bulb type gasket seals around the entire perimeter of the door / frame.
5.4. Doors shall open against static pressure unless obstructed by internal components. If obstructed by internal components on the positive sections requiring access, the doors shall open with pressure and shall be provided with a safety restraining mechanism. Doors used to access rotating equipment shall be provided with an OSHA approved safety latching mechanism requiring a tool to open and shall also have a highly visible, permanently fixed, caution sign on the exterior of the door. Doors with access to moving parts must also have locking hardware and meet current UL mechanical protection guidelines. Standard door size shall be 24” wide by 60” high unless restricted by height or section width.
5.5. Doors shall be provided with (double) (thermal pane wire) glass viewing windows as called out for on the unit drawings in the specifications. Minimum window size to be 9” x 9” with 12” x 12” provided door size permitting.
6. Bases:
6.1. Unit bases shall be constructed from structural steel channel iron or tubing around the entire perimeter of the unit and provided with intermediate structural tubing, channel and angle iron as required to support all internal components. All tubing, channel and angle joints shall be solid welded. Bolted or formed channel bases are not acceptable.
6.2. Base shall be provided with removable lifting lugs minimum (4) per section, properly located to assure uniform loading. Maximum spacing between lifting lugs shall be 120”.
6.3. Drain pans shall be 304 (316) Stainless Steel double-walled construction with solid welded seams for complete water capture and containment. Pans under cooling coils shall extend a minimum 12” passed the leaving face of the coil in direction of airflow. Drain Pans shall be fully recessed in the unit floor and all headers and return bends shall be located over the drain pan for collection of all condensate forming on headers and return bends. All coils shall be easily removable without cutting or removing any portion of the drain pan. Pans shall be insulated between the liner and the main pan. Pans shall be IAQ Double Sloping to a single drain. Drain connection shall be a minimum 1-1/4” diameter MIPS thread extending out through the channel base the same side as the coil connections unless other wised indicated on the drawings. Pans shall be provided for cooling coils, humidifiers, outside air intakes and under other components as required. Mastic coated drain pans are not acceptable as they are “non-Cleanable”.
6.4. All large openings (greater than one square foot) in the floor, including dampers openings, shall be covered with a removable powder coated heavy gauge steel grating bolted in place suitable for walking on which will prevent any personnel and large objects from falling through into the space below. Grating shall be capable of supporting minimum 300 pounds.
6.5. Provide a perimeter collar around the entire unit and around each floor opening to insure unit is watertight. The entire base shall act as a secondary drain pan to hold up to 1” of water.
6.6. All OSA (Outside Supply Air) openings shall have a recessed drain pan.
7. Coating:
7.1. All wall, roof, interior divider walls, racks, blank-offs and the Base Structure shall be coated with a Dry Powder - Baked Polyester coating. Each cabinet panel, panel liner and interior partition component is to be individually coated & baked following shearing, notching, punching, & forming to provide 100% powder coverage over the entire finished piece to include the interior, exterior and all metal edges.
The coating process is completed prior to assembly of the unit too unsure all joined surfaces (panel to panel joints), are covered. Spray or brush applied coatings on the exterior of the cabinet only are not acceptable. Powder Paint to have passed Salt Spray Resistance Test ASTM B 117-90 Minimum 1500 Hours, Impact Test ASTM D 2794-90 up to 160 lbs and Humidity Resistance Test ASTM D 2247-87 Minimum 1500-hour test w/ maximum blister 1/16 in/1 mm.
7.2. Powder Coated unit to be wet white (or Architect / Owner specified).
8. FANWALL Technology (FWT)
8.1. The Fanwall System, as manufactured by Huntair, shall consist of multiple, direct driven, arrangement 4 plenum fans constructed per AMCA requirements for the duty specified, (Class I, II, or III). All fans shall be selected to deliver the specified airflow quantity at the specified operating Total Static Pressure and specified fan/motor speed. The Fan Wall Array shall be selected to operate at a system Total Static Pressure that does not exceed 90% of the specified fan’s peak static pressure producing capability at the specified fan/motor speed. Each fan/motor (cube) (cartridge) shall include an 11-gauge, A60 Galvanized steel intake wall, 14 gauge spun steel fan inlet funnel, and an (11 gauge G90 Galvanized steel motor support plate and structure) (fully welded structural steel angle iron frame designed to support a pedestal mounted arrangement 4 direct drive fan/motor assembly). The fan intake wall, inlet funnel, and motor support structure shall be powder coated for superior corrosion resistance. All motors shall be standard pedestal mounted type, (ODP) (TEFC) (TENV), T-frame motors selected at the specified operating voltage, RPM, and efficiency as specified or as scheduled elsewhere. All motors shall include isolated bearings or shaft grounding. Each fan/motor cartridge shall be dynamically balanced to meet AMCA standard 204-96, better than category BV-5, to meet or exceed Grade 0.55 residual unbalance.
8.1.1. The FWT array shall be provided with coplanar acoustical silencers that reduces the bare fan discharge sound power levels by a minimum of 15 db re 10^-12 watts throughout the eight octave bands with center frequencies of 125, 250, 500, 1000, 2000, 4000, and 8000 HZ when compared to the same unit without the silencers. The silencers shall not increase the fan total static pressure, nor shall it increase the airway tunnel length of the Air Handling Unit when compared to the same FWT unit without the silencer array.
8.1.2. Alternate manufacturers must submit acoustical data for review and approval prior to the bid indicating that the proposed alternate equipment can meet all specified performance requirements without impacting the equipment performance or design features including duct connection location, unit weights, acoustical performance, or specified total fan HP for each FWT array. Proposals submitted which indicate a higher connected fan HP than specified or scheduled will not be accepted.
8.2. The fan array shall consist of multiple fan and motor ”cubes”, spaced in the air way tunnel cross section to provide a uniform air flow and velocity profile across the entire air way tunnel cross section and components contained therein. Each fan cube shall be (individually wired to a control panel containing a single VFD, as specified elsewhere, for the total connected HP for all fan motors contained in the FWT array) (wired to an individual VFD as specified elsewhere for each fan motor). Each individual VFD shall be controlled by a PLC. Wire sizing shall be determined, and installed, in accordance with applicable NEC standards.