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DocuSign Envelope ID: 9826C043- 4C32- 49CD- A4CC- DC28ABAB7CE7 <br />SECTION 239000 - METAL DUCTS <br />16.2 DUCT SCHEDULE <br />A. Fabricate ducts with galvanized sheet steel except as follows: <br />1. Fume Hood Exhaust Ducts: <br />a. Type 304, stainless -steel sheet (or other as required / listed on drawings). <br />b. Exposed to View: No. 4 finish. <br />C. Concealed: No. 2D finish. <br />d. Welded seams and flanged joints with watertight EPDM gaskets. <br />2. Moist Environment Ducts: Aluminum. <br />3. Commercial Kitchen Hood Exhaust Ducts: Comply with NFPA 96. <br />a. Exposed to View: Type 304, stainless -steel sheet, No. 4 finish. <br />b. Concealed: Type 304, stainless -steel sheet, No. 2D finish. <br />C. Welded seams and joints. <br />4. Dishwasher Hood Exhaust Ducts: <br />a. Type 304, stainless -steel sheet. <br />b. Exposed to View: No. 4 finish. <br />C. Concealed: No. 2D finish. <br />d. Welded seams and flanged joints with watertight EPDM gaskets. <br />B. Intermediate Reinforcement: <br />1. Galvanized -Steel Ducts: Galvanized steel. <br />2. Stainless -Steel Ducts: Galvanized steel. <br />3. Aluminum Ducts: Aluminum or galvanized sheet steel coated with zinc chromate. <br />C. Elbow Configuration: <br />1. Rectangular Duct: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and <br />Flexible," Figure 2 -2, "Rectangular Elbows." <br />a. Velocity 1000 fpm or Lower: <br />1) Radius Type RE 1 with minimum 0.5 radius -to- diameter ratio. <br />2) Mitered Type RE 4 without vanes. <br />b. Velocity 1000 to 1500 fpm: <br />1) Radius Type RE 1 with minimum 1.0 radius -to- diameter ratio. <br />2) Radius Type RE 3 with minimum 0.5 radius -to- diameter ratio and two vanes. <br />3) Mitered Type RE 2 with vanes complying with SMACNA's "HVAC Duct <br />Construction Standards - Metal and Flexible," Figure 2 -3, "Vanes and Vane <br />Runners," and Figure 2 -4, "Vane Support in Elbows." <br />C. Velocity 1500 fpm or Higher: <br />1) Radius Type RE 1 with minimum 1.5 radius -to- diameter ratio. <br />2) Radius Type RE 3 with minimum 1.0 radius -to- diameter ratio and two vanes. <br />3) Mitered Type RE 2 with vanes complying with SMACNA's "HVAC Duct <br />Construction Standards - Metal and Flexible," Figure 2 -3, "Vanes and Vane <br />Runners," and Figure 2 -4, "Vane Support in Elbows." <br />2. Round Duct: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and <br />Flexible," Figure 3 -3, "Round Duct Elbows." <br />a. Minimum Radius -to- Diameter Ratio and Elbow Segments: Comply with SMACNA's <br />"HVAC Duct Construction Standards - Metal and Flexible," Table 3 -1, "Mitered <br />Elbows." Elbows with less than 90- degree change of direction have proportionately <br />fewer segments. <br />1) Velocity 1000 fpm or Lower: 0.5 radius -to- diameter ratio and three segments <br />for 90- degree elbow. <br />2) Velocity 1000 to 1500 fpm: 1.0 radius -to- diameter ratio and four segments for <br />90- degree elbow. <br />3) Velocity 1500 fpm or Higher: 1.5 radius -to- diameter ratio and five segments for <br />90- degree elbow. <br />b. Round Elbows, 12 Inches and Smaller in Diameter: Stamped or pleated. <br />C. Round Elbows, 14 Inches and Larger in Diameter: Standing seam or Welded. <br />D. Branch Configuration: <br />1. Rectangular Duct: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and <br />Flexible," Figure 2 -6, "Branch Connections." <br />a. Rectangular Main to Rectangular Branch: 45- degree entry. <br />b. Rectangular Main to Round Branch: Spin in. <br />2. Round: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," <br />Figure 3 -4, "90 Degree Tees and Laterals," and Figure 3 -5, "Conical Tees." Saddle taps are <br />permitted in existing duct. <br />a. Velocity 1000 fpm or Lower: 90- degree tap. <br />b. Velocity 1000 to 1500 fpm: Conical tap. <br />C. Velocity 1500 fpm or Higher: 45- degree lateral. <br />Reece, Noland & McElrath, Inc. 239000-5 Orange County Board of Elections <br />Orange Co., NC 05/04/18 <br />