Loading...
HomeMy WebLinkAbout23 31 13 Metal DuctsBEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 1 OF 14 MARCH 29, 2013 SECTION 233113 -- METAL DUCTS PART 1 GENERAL 1.1 SUBMITTALS A. Product Data: Provide for each type of the following products: 1. Liners and adhesives. 2. Sealants and gaskets. B. Provide Shop Drawings as Follows: 1. Fabrication, assembly, and installation, including plans, elevations, sections, components, and attachments to other work. 2. Factory- and shop-fabricated ducts and fittings. 3. Duct layout indicating sizes, configuration, liner material, and static- pressure classes. 4. Elevation of top of ducts. 5. Fittings. 6. Seam and joint construction. 7. Penetrations through fire-rated and other partitions. 8. Equipment installation based on equipment being used on Project. 9. Locations for duct accessories, including dampers, turning vanes, and access doors and panels. 10. Hangers and supports, including methods for duct and building attachment and vibration isolation. C. Field quality-control reports. 1.2 QUALITY ASSURANCE A. Welding Qualifications: Qualify procedures and personnel according to [AWS D1.1/D1.1M, "Structural Welding Code - Steel," for hangers and supports.] [AWS D1.2/D1.2M, "Structural Welding Code - Aluminum," for aluminum supports.] [AWS D9.1M/D9.1, "Sheet Metal W elding Code," for duct joint and seam welding.] B. Welding Qualifications: Qualify procedures and personnel according to the following: 1. AWS D1.1/D1.1M, "Structural Welding Code - Steel," for hangers and supports. 2. AWS D1.2/D1.2M, "Structural Welding Code - Aluminum," for aluminum supports. 3. AWS D9.1M/D9.1, "Sheet Metal Welding Code," for duct joint and seam welding. BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 2 OF 14 MARCH 29, 2013 C. ASHRAE Compliance: Applicable requirements in ASHRAE 62.1, Section 5 - "Systems and Equipment" and Section 7 - "Construction and System Start- Up." D. ASHRAE/IESNA Compliance: Applicable requirements in ASHRAE/IESNA 90.1, Section 6.4.4 - "HVAC System Construction and Insulation." PART 2 PRODUCTS 2.1 PERFORMANCE REQUIREMENTS A. Structural Performance: Duct hangers and supports shall withstand the effects of gravity loads and stresses within limits and under conditions described in SMACNA's "HVAC Duct Construction Standards - Metal and Flexible". B. Airstream Surfaces: Surfaces in contact with the airstream shall comply with requirements in ASHRAE 62.1. 2.2 SINGLE-WALL RECTANGULAR DUCTS AND FITTINGS A. General Fabrication Requirements: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible" based on indicated static- pressure class unless otherwise indicated. B. Transverse Joints: Select joint types and fabricate according to SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 2-1, "Rectangular Duct/Transverse Joints," for static-pressure class, applicable sealing requirements, materials involved, duct-support intervals, and other provisions in SMACNA's "HVAC Duct Construction Standards - Metal and Flexible." C. Longitudinal Seams: Select seam types and fabricate according to SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 2-2, "Rectangular Duct/Longitudinal Seams," for static-pressure class, applicable sealing requirements, materials involved, duct-support intervals, and other provisions in SMACNA's "HVAC Duct Construction Standards - Metal and Flexible." D. Elbows, Transitions, Offsets, Branch Connections, and Other Duct Construction: Select types and fabricate according to SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Chapter 4, "Fittings and Other Construction," for static-pressure class, applicable sealing requirements, materials involved, duct-support intervals, and other provisions in SMACNA's "HVAC Duct Construction Standards - Metal and Flexible." E. Longitudinal Seams: Select seam types and fabricate according to SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 2-2, "Rectangular Duct/Longitudinal Seams," for static-pressure class, applicable sealing requirements, materials involved, duct-support intervals, BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 3 OF 14 MARCH 29, 2013 and other provisions in SMACNA's "HVAC Duct Construction Standards - Metal and Flexible." 2.3 SINGLE-WALL ROUND[ AND FLAT-OVAL] DUCTS AND FITTINGS A. General Fabrication Requirements: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Chapter 3, "Round, Oval, and Flexible Duct," based on indicated static-pressure class unless otherwise indicated. 1. Manufacturers: Subject to compliance with requirements, available manufacturers offering products that may be incorporated into the Work include, but are not limited to, the following: a. Lindab Inc. b. McGill AirFlow LLC. c. SEMCO Incorporated. d. Sheet Metal Connectors, Inc. e. Spiral Manufacturing Co., Inc. B. Flat-Oval Ducts: Indicated dimensions are the duct width (major dimension) and diameter of the round sides connecting the flat portions of the duct (minor dimension). C. Transverse Joints: Select joint types and fabricate according to SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 3-1, "Round Duct Transverse Joints," for static-pressure class, applicable sealing requirements, materials involved, duct-support intervals, and other provisions in SMACNA's "HVAC Duct Construction Standards - Metal and Flexible." D. Longitudinal Seams: Select seam types and fabricate according to SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 3-2, "Round Duct Longitudinal Seams," for static-pressure class, applicable sealing requirements, materials involved, duct-support intervals, and other provisions in SMACNA's "HVAC Duct Construction Standards - Metal and Flexible." E. Tees and Laterals: Select types and fabricate according to SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 3-5, "90 Degree Tees and Laterals," and Figure 3-6, "Conical Tees," for static- pressure class, applicable sealing requirements, materials involved, duct- support intervals, and other provisions in SMACNA's "HVAC Duct Construction Standards - Metal and Flexible." 2.4 SHEET METAL MATERIALS A. General Material Requirements: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible" for acceptable materials, material thicknesses, and duct construction methods unless otherwise indicated. Sheet metal materials shall be free of pitting, seam marks, roller marks, stains, discolorations, and other imperfections. BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 4 OF 14 MARCH 29, 2013 B. Galvanized Sheet Steel: Comply with ASTM A 653/A 653M. 1. Galvanized Coating Designation: G60. 2. Finishes for Surfaces Exposed to View: Mill phosphatized. C. Tie Rods: Galvanized steel, 1/4-inch (6-mm) minimum diameter for lengths 36 inches (900 mm) or less; 3/8-inch (10-mm) minimum diameter for lengths longer than 36 inches (900 mm). 2.5 DUCT LINER A. Fibrous-Glass Duct Liner: Comply with ASTM C 1071, NFPA 90A, or NFPA 90B; and with NAIMA AH124, "Fibrous Glass Duct Liner Standard." 1. Manufacturers: Subject to compliance with requirements, available manufacturers offering products that may be incorporated into the Work include, but are not limited to, the following: a. CertainTeed Corporation; Insulation Group. b. Johns Manville. c. Knauf Insulation. d. Owens Corning. e. Maximum Thermal Conductivity: 1) Type I, Flexible: 0.27 Btu x in./h x sq. ft. x deg F (0.039 W/m x K) at 75 deg F (24 deg C) mean temperature. 2) Type II, Rigid: 0.23 Btu x in./h x sq. ft. x deg F (0.033 W/m x K) at 75 deg F (24 deg C) mean temperature. 2. Antimicrobial Erosion-Resistant Coating: Apply to the surface of the liner that will form the interior surface of the duct to act as a moisture repellent and erosion-resistant coating. Antimicrobial compound shall be tested for efficacy by an NRTL and registered by the EPA for use in HVAC systems. 3. Water-Based Liner Adhesive: Comply with NFPA 90A or NFPA 90B and with ASTM C 916. a. For indoor applications, use adhesive that has a VOC content of 80 g/L or less when calculated according to 40 CFR 59, Subpart D (EPA Method 24). b. Adhesive shall comply with the testing and product requirements of the California Department of Health Services' "Standard Practice for the Testing of Volatile Organic Emissions from Various Sources Using Small-Scale Environmental Chambers." B. Shop Application of Duct Liner: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 7-11, "Flexible Duct Liner Installation." 1. Adhere a single layer of indicated thickness of duct liner with at least 90 percent adhesive coverage at liner contact surface area. Attaining indicated thickness with multiple layers of duct liner is prohibited. BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 5 OF 14 MARCH 29, 2013 2. Apply adhesive to transverse edges of liner facing upstream that do not receive metal nosing. 3. Butt transverse joints without gaps, and coat joint with adhesive. 4. Fold and compress liner in corners of rectangular ducts or cut and fit to ensure butted-edge overlapping. 5. Do not apply liner in rectangular ducts with longitudinal joints, except at corners of ducts, unless duct size and dimensions of standard liner make longitudinal joints necessary. 6. Secure liner with mechanical fasteners 4 inches (100 mm) from corners and at intervals not exceeding 12 inches (300 mm) transversely; at 3 inches (75 mm) from transverse joints and at intervals not exceeding 18 inches (450 mm) longitudinally. 2.6 SEALANT AND GASKETS A. General Sealant and Gasket Requirements: Surface-burning characteristics for sealants and gaskets shall be a maximum flame-spread index of 25 and a maximum smoke-developed index of 50 when tested according to UL 723; certified by an NRTL. B. Water-Based Joint and Seam Sealant: 1. Application Method: Brush on. 2. Solids Content: Minimum 65 percent. 3. Shore A Hardness: Minimum 20. 4. Water resistant. 5. Mold and mildew resistant. 6. VOC: Maximum 75 g/L (less water). 7. Maximum Static-Pressure Class: 10-inch wg (2500 Pa), positive and negative. 8. Service: Indoor or outdoor. 9. Substrate: Compatible with galvanized sheet steel (both PVC coated and bare), stainless steel, or aluminum sheets. C. Flange Gaskets: Butyl rubber, neoprene, or EPDM polymer with polyisobutylene plasticizer. D. Round Duct Joint O-Ring Seals: 1. Seal shall provide maximum leakage class of 3 cfm/100 sq. ft. at 1-inch wg (0.14 L/s per sq. m at 250 Pa) and shall be rated for 10-inch wg (2500- Pa) static-pressure class, positive or negative. 2. EPDM O-ring to seal in concave bead in coupling or fitting spigot. 3. Double-lipped, EPDM O-ring seal, mechanically fastened to factory- fabricated couplings and fitting spigots. 2.7 HANGERS AND SUPPORTS A. Hanger Rods for Noncorrosive Environments: Cadmium-plated steel rods and nuts. BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 6 OF 14 MARCH 29, 2013 B. Strap and Rod Sizes: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Table 5-1 (Table 5-1M), "Rectangular Duct Hangers Minimum Size," and Table 5-2, "Minimum Hanger Sizes for Round Duct." C. Steel Cables for Galvanized-Steel Ducts: Galvanized steel complying with ASTM A 603. D. Steel Cable End Connections: Cadmium-plated steel assemblies with brackets, swivel, and bolts designed for duct hanger service; with an automatic-locking and clamping device. E. Duct Attachments: Sheet metal screws, blind rivets, or self-tapping metal screws; compatible with duct materials. F. Trapeze and Riser Supports: 1. Supports for Galvanized-Steel Ducts: Galvanized-steel shapes and plates. 2.8 MANUAL VOLUME DAMPERS A. Standard, Steel, Manual Volume Dampers: 1. Suitable for horizontal or vertical applications. 2. Frames: a. Hat-shaped, galvanized-steel channels, 0.064-inch (1.62-mm) minimum thickness. b. Mitered and welded corners. c. Flanges for attaching to walls and flangeless frames for installing in ducts. 3. Blades: a. Multiple or single blade. b. Parallel- or opposed-blade design. c. Stiffen damper blades for stability. d. Galvanized-steel, 0.064 inch (1.62 mm) thick. 4. Blade Axles: Galvanized steel. 5. Bearings: a. Molded synthetic. b. Dampers in ducts with pressure classes of 3-inch wg (750 Pa) or less shall have axles full length of damper blades and bearings at both ends of operating shaft. B. Damper Hardware: 1. Zinc-plated, die-cast core with dial and handle made of 3/32-inch- (2.4- mm-) thick zinc-plated steel, and a 3/4-inch (19-mm) hexagon locking nut. 2. Include center hole to suit damper operating-rod size. BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 7 OF 14 MARCH 29, 2013 3. Include elevated platform for insulated duct mounting. 2.9 TURNING VANES A. Manufactured Turning Vanes for Metal Ducts: Curved blades of galvanized sheet steel; support with bars perpendicular to blades set; set into vane runners suitable for duct mounting. 1. Acoustic Turning Vanes: Fabricate airfoil-shaped aluminum extrusions with perforated faces and fibrous-glass fill. B. General Requirements: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible"; Figures 4-3, "Vanes and Vane Runners," and 4-4, "Vane Support in Elbows." C. Vane Construction: Single wall for ducts up to 48 inches (1200 mm) wide and double wall for larger dimensions. 2.10 DUCT-MOUNTED ACCESS DOORS A. Duct-Mounted Access Doors: Fabricate access panels according to SMACNA's "HVAC Duct Construction Standards - Metal and Flexible"; Figures 7-2 (7-2M), "Duct Access Doors and Panels," and 7-3, "Access Doors - Round Duct." 1. Door: a. Double wall, rectangular. b. Galvanized sheet metal with insulation fill and thickness as indicated for duct pressure class. c. Hinges and Latches: 1-by-1-inch (25-by-25-mm) butt or piano hinge and cam latches. d. Fabricate doors airtight and suitable for duct pressure class. 2. Frame: Galvanized sheet steel, with bend-over tabs and foam gaskets. 3. Number of Hinges and Locks: a. Access Doors Less Than 12 Inches (300 mm) Square: No hinges and two sash locks. b. Access Doors up to 18 Inches (460 mm) Square: Two hinges and two sash locks. c. Access Doors up to 24 by 48 Inches (600 by 1200 mm): Three hinges and two compression latches with outside and inside handles. d. Access Doors Larger Than 24 by 48 Inches (600 by 1200 mm): Four hinges and two compression latches with outside and inside handles. 2.11 FLEXIBLE CONNECTORS A. Materials: Flame-retardant or noncombustible fabrics. BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 8 OF 14 MARCH 29, 2013 B. Coatings and Adhesives: Comply with UL 181, Class 1. C. Metal-Edged Connectors: Factory fabricated with a fabric strip 3-1/2 inches (89 mm) wide attached to 2 strips of 2-3/4-inch- (70-mm-) wide, 0.028-inch- (0.7-mm-) thick, galvanized sheet steel or 0.032-inch- (0.8-mm-) thick aluminum sheets. Provide metal compatible with connected ducts. D. Indoor System, Flexible Connector Fabric: Glass fabric double coated with neoprene. 1. Minimum Weight: 26 oz./sq. yd. (880 g/sq. m). 2. Tensile Strength: 480 lbf/inch (84 N/mm) in the warp and 360 lbf/inch (63 N/mm) in the filling. 3. Service Temperature: Minus 40 to plus 200 deg F (Minus 40 to plus 93 deg C). E. Outdoor System, Flexible Connector Fabric: Glass fabric double coated with weatherproof, synthetic rubber resistant to UV rays and ozone. 1. Minimum Weight: 24 oz./sq. yd. (810 g/sq. m). 2. Tensile Strength: 530 lbf/inch (93 N/mm) in the warp and 440 lbf/inch (77 N/mm) in the filling. 3. Service Temperature: Minus 50 to plus 250 deg F (Minus 45 to plus 121 deg C). PART 3 EXECUTION 3.1 DUCT INSTALLATION A. Drawing plans, schematics, and diagrams indicate general location and arrangement of duct system. Indicated duct locations, configurations, and arrangements were used to size ducts and calculate friction loss for air- handling equipment sizing and for other design considerations. Install duct systems as indicated unless deviations to layout are approved on Shop Drawings and Coordination Drawings. B. Install ducts according to SMACNA's "HVAC Duct Construction Standards - Metal and Flexible" unless otherwise indicated. C. Install round [ and flat-oval] ducts in maximum practical lengths. D. Install ducts with fewest possible joints. E. Install factory- or shop-fabricated fittings for changes in direction, size, and shape and for branch connections. F. Unless otherwise indicated, install ducts vertically and horizontally, and parallel and perpendicular to building lines. BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 9 OF 14 MARCH 29, 2013 G. Install ducts close to walls, overhead construction, columns, and other structural and permanent enclosure elements of building. H. Install ducts with a clearance of 1 inch (25 mm), plus allowance for insulation thickness. I. Route ducts to avoid passing through transformer vaults and electrical equipment rooms and enclosures. J. Where ducts pass through non-fire-rated interior partitions and exterior walls and are exposed to view, cover the opening between the partition and duct or duct insulation with sheet metal flanges of same metal thickness as the duct. Overlap openings on four sides by at least 1-1/2 inches (38 mm). K. Where ducts pass through fire-rated interior partitions and exterior walls, install fire dampers. L. Protect duct interiors from moisture, construction debris and dust, and other foreign materials.[ Comply with SMACNA's "IAQ Guidelines for Occupied Buildings Under Construction," Appendix G, "Duct Cleanliness for New Construction Guidelines."] 3.2 INSTALLATION OF EXPOSED DUCTWORK A. Protect ducts exposed in finished spaces from being dented, scratched, or damaged. B. Trim duct sealants flush with metal. Create a smooth and uniform exposed bead. Do not use two-part tape sealing system. C. Grind welds to provide smooth surface free of burrs, sharp edges, and weld splatter. When welding stainless steel with a No. 3 or 4 finish, grind the welds flush, polish the exposed welds, and treat the welds to remove discoloration caused by welding. D. Maintain consistency, symmetry, and uniformity in the arrangement and fabrication of fittings, hangers and supports, duct accessories, and air outlets. E. Repair or replace damaged sections and finished work that does not comply with these requirements. 3.3 DUCT SEALING A. Seal ducts for leakage classes in table below: DUCT TYPE LEAKAGE CLASS, CFM/100 ft at 1” wg Metal (flexible excluded) Round and Flat Oval [3] BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 10 OF 14 MARCH 29, 2013 Rectangular [6] Flexible [6] B. Note: Leakage classes for specific applications may be specified elsewhere in this specification. MINIMUM DUCT SEAL LEVELA DUCT TYPE Duct Location Supply <2 in. w.c.b >2 in. w.c.b. Exhaust Return Outdoor A A C A Unconditioned Spaces B A C B Conditioned Spacesc C B B C a See description of seal levels below. b Duct design static pressure classification. c Includes indirectly conditioned spaces such as return air plenums. C. Longitudinal seams are joints oriented in the direction of airflow. Transverse joints are connections of two duct sections oriented perpendicular to airflow. Duct wall penetrations are openings made by any screw fastener, pipe, rod, or wire. Spiral lock seams in a round or flat oval duct need not be sealed. All other connections are considered transverse joints, including but not limited to spin-ins, taps, and other branch connections, access door frames and jambs, duct connections to equipment, etc. 3.4 HANGER AND SUPPORT INSTALLATION A. Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Chapter 5, "Hangers and Supports." B. Building Attachments: Concrete inserts, powder-actuated fasteners, or structural-steel fasteners appropriate for construction materials to which hangers are being attached. 1. Where practical, install concrete inserts before placing concrete. 2. Install powder-actuated concrete fasteners after concrete is placed and completely cured. 3. Use powder-actuated concrete fasteners for standard-weight aggregate concretes or for slabs more than 4 inches (100 mm) thick. BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 11 OF 14 MARCH 29, 2013 4. Do not use powder-actuated concrete fasteners for lightweight-aggregate concretes or for slabs less than 4 inches (100 mm) thick. 5. Do not use powder-actuated concrete fasteners for seismic restraints. C. Hanger Spacing: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Table 5-1 (Table 5-1M), "Rectangular Duct Hangers Minimum Size," and Table 5-2, "Minimum Hanger Sizes for Round Duct," for maximum hanger spacing; install hangers and supports within 24 inches (610 mm) of each elbow and within 48 inches (1200 mm) of each branch intersection. D. Hangers Exposed to View: Threaded rod and angle or channel supports. E. Support vertical ducts with steel angles or channel secured to the sides of the duct with welds, bolts, sheet metal screws, or blind rivets; support at each floor and at a maximum intervals of 16 feet (5 m). F. Install upper attachments to structures. Select and size upper attachments with pull-out, tension, and shear capacities appropriate for supported loads and building materials where used. 3.5 CONNECTIONS A. Make connections to equipment with flexible connectors. B. Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible" for branch, outlet and inlet, and terminal unit connections. 3.6 PAINTING A. Paint interior of metal ducts that are visible through registers and grilles and that do not have duct liner. Apply one coat of flat, black, latex paint over a compatible galvanized-steel primer. 3.7 FIELD QUALITY CONTROL A. Perform tests and inspections. B. Leakage Tests: 1. Comply with SMACNA's "HVAC Air Duct Leakage Test Manual." Submit a test report for each test. 2. Test the following systems: a. Supply Ducts with a Pressure Class of 2-Inch wg (500 Pa) or Higher: Test representative duct sections totaling no less than 50 percent of total installed duct area for each designated pressure class. b. Return Ducts with a Pressure Class of 2-Inch wg (500 Pa) or Higher: Test representative duct sections totaling no less than 50 percent of total installed duct area for each designated pressure class. BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 12 OF 14 MARCH 29, 2013 c. Exhaust Ducts with a Pressure Class of 2-Inch wg (500 Pa) or Higher: Test representative duct sections totaling no less than 50 percent of total installed duct area for each designated pressure class. 3. Disassemble, reassemble, and seal segments of systems to accommodate leakage testing and for compliance with test requirements. 4. Test for leaks before applying external insulation. 5. Conduct tests at static pressures equal to maximum design pressure of system or section being tested. If static-pressure classes are not indicated, test system at maximum system design pressure. Do not pressurize systems above maximum design operating pressure. 6. Give seven days' advance notice for testing. C. Duct system will be considered defective if it does not pass tests and inspections. D. Prepare test and inspection reports. 3.8 DUCT CLEANING A. Clean new and existing duct system(s) before testing, adjusting, and balancing. B. Use service openings for entry and inspection. 1. Create new openings and install access panels appropriate for duct static- pressure class if required for cleaning access. Provide insulated panels for insulated or lined duct. Patch insulation and liner as recommended by duct liner manufacturer. 2. Disconnect and reconnect flexible ducts as needed for cleaning and inspection. 3. Remove and reinstall ceiling to gain access during the cleaning process. C. Clean the following components by removing surface contaminants and deposits: 1. Air outlets and inlets (registers, grilles, and diffusers). 2. Supply, return, and exhaust fans including fan housings, plenums (except ceiling supply and return plenums), scrolls, blades or vanes, shafts, baffles, dampers, and drive assemblies. 3. Coils and related components. 4. Return-air ducts, dampers, actuators, and turning vanes except in ceiling plenums and mechanical equipment rooms. 5. Supply-air ducts, dampers, actuators, and turning vanes. 6. Dedicated exhaust and ventilation components and makeup air systems. 3.9 START UP A. Air Balance: Comply with requirements in Division 23 Section "Testing, Adjusting, and Balancing for HVAC." BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 13 OF 14 MARCH 29, 2013 3.10 DUCT SCHEDULE A. Supply Duct Pressure Class: 1. Pressure Class: Positive 2-inch wg (500 Pa). B. Return Duct Pressure Class: 1. Pressure Class: Positive or negative 2-inch wg (500 Pa). C. Exhaust Duct Pressure Class: 1. Ducts Connected to Fans Exhausting (ASHRAE 62.1, Class 1 and 2) Air: a. Pressure Class: Negative 2-inch wg (500 Pa). D. Elbow Configuration: 1. Rectangular Duct: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 4-2, "Rectangular Elbows." a. Velocity 1000 fpm (5 m/s) or Lower: 1) Radius Type RE 1 with minimum 0.5 radius-to-diameter ratio. 2) Mitered Type RE 4 without vanes. b. Velocity 1000 to 1500 fpm (5 to 7.6 m/s): 1) Radius Type RE 1 with minimum 1.0 radius-to-diameter ratio. 2) Radius Type RE 3 with minimum 0.5 radius-to-diameter ratio and two vanes. 3) Mitered Type RE 2 with vanes complying with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 4-3, "Vanes and Vane Runners," and Figure 4-4, "Vane Support in Elbows." c. Velocity 1500 fpm (7.6 m/s) or Higher: 1) Radius Type RE 1 with minimum 1.5 radius-to-diameter ratio. 2) Radius Type RE 3 with minimum 1.0 radius-to-diameter ratio and two vanes. 3) Mitered Type RE 2 with vanes complying with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 4-3, "Vanes and Vane Runners," and Figure 4-4, "Vane Support in Elbows." 2. Round Duct: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 3-4, "Round Duct Elbows." a. Minimum Radius-to-Diameter Ratio and Elbow Segments: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Table 3-1, "Mitered Elbows." Elbows with less than 90- degree change of direction have proportionately fewer segments. BEARDSLEY DESIGN ASSOCIATES CORNELL – NCP METAL DUCTS STANDARD SPECIFICATIONS 23 31 13 – PAGE 14 OF 14 MARCH 29, 2013 1) Velocity 1000 fpm (5 m/s) or Lower: 0.5 radius-to-diameter ratio and three segments for 90-degree elbow. 2) Velocity 1000 to 1500 fpm (5 to 7.6 m/s): 1.0 radius-to-diameter ratio and four segments for 90-degree elbow. 3) Velocity 1500 fpm (7.6 m/s) or Higher: 1.5 radius-to-diameter ratio and five segments for 90-degree elbow. 4) Radius-to Diameter Ratio: 1.5. b. Round Elbows, 12 Inches (305 mm) and Smaller in Diameter: Stamped or pleated. c. Round Elbows, 14 Inches (356 mm) and Larger in Diameter: Standing seam. E. Branch Configuration: 1. Rectangular Duct: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 4-6, "Branch Connection." a. Rectangular Main to Rectangular Branch: 45-degree entry. b. Rectangular Main to Round Branch: Spin in. 2. Round and Flat Oval: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 3-5, "90 Degree Tees and Laterals," and Figure 3-6, "Conical Tees." Saddle taps are permitted in existing duct. a. Velocity 1000 fpm (5 m/s) or Lower: 90-degree tap. b. Velocity 1000 to 1500 fpm (5 to 7.6 m/s): Conical tap. c. Velocity 1500 fpm (7.6 m/s) or Higher: 45-degree lateral. END OF SECTION 23 31 13