Document joxk0n0rNQnwkBJZNvKwOkXQ

656 CHAPTER 31 1951 Guide Air Duct Design 657 CU FT OF AIR PER MINUTE CU FT OF AIR PER MINUTE Fig. 1. Friction op Air in Straight Ducts For Volumes of 10 to 2000 cfm (Based on Standard Air cf9.076 lb per ou ft density flowing through average, clean, round, galvanized metal duets having approximately 40 joints per 100 ft.) No safety factor included. Caution: Do not extrapo late below chart. .02 .03 .04 .06 .08 J .2 .3 .4 6~tT I 2 3 4 6--fTTo FRICTION LOSS IN INCHES OF WATER PER 100 FT Fig. 2. Friction of Air in Straight Ducts For Volumes of 1000 to 100,000 cfm TM*^!e<L?1i.St^n`lar<1 Air.of ?*?* lb per cu ft density flowing through average, clean, round, galvanized metal ducts having approximately 40 joints per 100 ft.) No safety factor twlyded. Figs. 1 and 2, covering volume ranges of 10 to 2000 cfm, and 1000 to 100,000 cfm, respectively. These charts were developed by the A.S.H.V.E. Re search Laboratory.1 They do not include any safely factor. The charts, Figs. 1 and 2, were constructed from the basic flow equation for the pressure loss in circular ducts (see Chapter 4):