Document JNeVDKGzpZjd50Xyr4aN5xVBK

442 CHAPTER 18 . 1952 Guide OUTLINE OF DESIGN PROCEDURE The data underlying the design procedure are given in detail in a circular1 issued by the University of Illinois. In this procedure the design of the warm-air duct system is considered as an entire unit, sp that for a given heat loss, the sizes of leaders, stacks, boots, stackheads, and registers are all correlated. Similarly in the case of return ducts, the selection specifies a complete unit consisting of return grille, return duct, and shoe connection. Recommended Standard Sizes For the purpose of simplification and standardization, selected combina tions of commercial sizes of warm air pipes, return air pipes, ducts, grilles, fittings, and registers are. designated as Combination Numbers. The numbers assigned and the combinations selected as standard are listed in the following Tables 1 to 4 inclusive.* Table 1. First Stoby Wabm-Aik Ducts* Combination . :no. Leadbb Pipe - Diameter, In. Floor Register Size, In. Baseboard Size' Extension i 8 .. 8 x 10 10 x 8 : 2M . 2 9 9 x 12 12 x 8 , 2M 3 10 10 x 12 12 x 9 3A 4 12 12 x 14 13x11 5H 5 14 14 x 16 ' * When the calculations indicate a requirement for a given room greater than Combination No. 4, two or more smaller units totalling the required capacity are recommended. Table 2. Second Stoby Warm-Aib Ducts--Single Wall Stacks and Fittings Combi nation No. Leadeb Pipe Diameter, In. SlACKb Size In. Register Size, In. Baseboard Size Extension ' Sidewall ii 12 . 14 . ' 15 16 8 9 10 12 12 10 x 3M 12 x 3'H 14 x3M 12 x 5M 14 x5M 8 x 10 9 x 12 10 x 12 10 x 8 12 x 8 12 x 8 ' 12 x- 9 13 x 11. : 2M 2K ... 2H 3H 5M. 10x8 , 12 x,8 12 x 8 b Recommended stack sixes. Tables may also be applied to 3 in. and 3 1/2 in. stack depths. Table 3. Second Stoby Wabm-Aib Ducts--Double Wall Stacks and Fittings Combi nation No. Leader Pipe Diameter, In. Stack Size, In. Internal External Floor Register Size, In. Baseboard Size Extension .Sidewall 21 8 214 X 10 3H x 10% 8 x 10 ; 10 x 8 2>i 10 x 8 22 8 . 3 x 10 3% xlO% 8 x 10 10 x 8 2M 10 x 8 23' 9 2'A x 12 3^' x 12^ 9 x 12 12 x 8 2K 12 x 8 24 . 9 3 x 12 3Ys xl2% 9 x 12 12 x 8 21i 12 x 8 . c Commercial sixes vary 1/8 in. from values shown. r* i Gravity'Warm Air Systems 443 Table 4. Return Aik Ducts Combi nation NO. 31 . 32 . 33 34 35 36 37 38 Duct Dia. In. 10 12 14 16 18 20 22 24 Area at Shoe Con nection. Sq In. * Metal Grille Sizes * Choose One A Bc When Joist Lining is Used* When Duct is Used No. of Joists Lined Minimum* Depth. la. Choose One 8x14 10x12 i 6x30 8x24 12x14 i .170 8x30 10x24 14x16 i 220 10x30 12x24 2 280 12x30 14x24 2 340 14x30 18x24 2 420 18x30 2 500 20x30 2 7 14 x 6 12 x 8 9 22 x 6 16 x 8 12 28 x 6 22 x 8 8 28 x 8 22 x 10 10 36 x 8 . 28 x 10 12.5 36x10 30 x 12 15.0 42x10 36x12 18.0 42x12 36x14 d Based on 14 in. space between joists. * Use full depth of joist except when jpist depth is less than minimum depth required, taken pan must be used. fG HI Fig. 2. Typical Warm Aik Boots Table 5. Resistances op Warm Air Boot Combinations Expressed in Elbow Equivalents Warm Air Boot . A B C d: E F G H I Name op Combination 45-Deg Angle Boot and 45-Dee Elbow 90-Deg Angle Boot Universal Boot and 90-Deg Elbow End Boot Offset Boot 45-Deg Angle Floor Register--Second Story Offset Offset Equivalent No. op 90-Dbg Elbows i .i i 2 214 A 3 3 2 Cl*