Document jMj7Q4Ne9YZY6gpXMXQX81N2

454 CHAPTER 19 1954 Guide* Table 1: First Stout Warm-Air Ducts* Combination No. Leader Pipe Diameter, In. Floor Register Size, In. Size Baseboard Extension Throat Size i 8 8 x 10 10 x 8 m. 6)4 x 10 m2 9 9 x 12 12 x 8 2)4 X 12 m3 10 10 x 12 12 x 9 3)4 x 12 4 12 12 x 14 13 x 11 5)4 9)4 X 13 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 Story Warm-Air Ducts--Single Wall Stacks and Fittings, Combi nation No. Leader Pipe Diameter, In. STACKb Size, ' In. Floor Register Size, In. Baseboard Size Extension Sidewall u8 12 9 14' 10 15 12 16 12 10 x 3)4 12 x 3)4 14x3)4 12 x 5% 14 x 5)4 8 x 10 9 x 12 10 x 14 10 x 8 12 x 8 13 x 11 12 x 9 13 x 11 2)4 10 x 8 2)4 12 x 8 2)4 3M 5)4 b Recommended stack sites. Tables may also be applied to 3 in. and 3 1/2 in. stack depths. Table 3. Second Story Warm-Air Ducts--Double Wald Stacks and Fittings Combi nation No. Leader' ' Pipe Diameter, In. Stack Size, In. Internal External Floor Register Size, In. Baseboard Size Extension Sidewall 21 ' 8 234* x 10 3)4' x 10)4 8 x 10 22 .8 ' 3 x 10 m x 10)4 8 x 10 23 9 2)4* X 12 3)4' X 12)4 9 xT2 24 9 3 x 12 3)4 x 12)4 9 x 12 C Commercial sizes vary 1/S in. from values shown. 10 x 8 10 x 8 12 x 8 12 x 8 , 2)4 2)4 2)4 2)4 10x8 * 10 x 8 12x8 12 x 8 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, gnlfe fittings, and registers are designated as Combination Numbers. The numbers assigned and the combinations selected as standard are listed the following Tables 1 to 4 inclusive.3 The selected types of boots are shown in Fig. 2, and their resistances ex pressed in equivalent elbows are shown in Table 5. It is essential that free areas be maintained throughout fittings. Figs.^ 3 and 4 show recommended practice as given in Manual 5 of the Gravity .Warm Air Systems Ddct Dia. Duct at Area SOE Con Metal Grille Sizes -I * Use full--de.p-t.h..o. fojioxwisjtveoxeciewpetewnhjeonisjtos.ist depth is less than minimum depth required, when..pa.h.must &e used, NWAH & ACA. For construction, design features, and ratings, of gravity furnaces see Chapter 16. Carrying Capacity H Fig. 2. Typical Warm Air Boots