Document DvkX056zRDKYL0w0RJe5xRx9O

792 CHAPTER 31 1958 Guide Air Duct Design 793 CU FT OF AIR PER MINUTE CU FT OF AIR PER MINUTE Fig. 2. Fbiction op Air in Straight Ducts For Volumes of 10 to 2000 cfm (Based on Standard Air of 0.075 lb percu ft densityflowing through average, clean,round, g ducts having approximately 40 joints per 100 ft.) Caution: Do notextrapolate below chart. Fig. 3. Friction op Air in Straight Ducts ' For Volumes of 1000 to 100,000 cfm rcetaWWi^a ^andnrd Air of 0.075 lb per cu ft density flowing through average, clean, round, galvanized ucte havmg approximately 40 joints per 100 ft.) [^Cp?rs may be obtained from Figs. 5 and 6. The correction factors shown Tahl^ f 3were computed for the value of e, the roughness in feet, shown in 1 Most ductwork today is fabricated from galvanized-iron or form^h*111 S^ee^ metedi or flexible tubing. Fig. 6 presents in graphical cor + r .recommended correction factors for aluminum ductwork.4 The rect friction loss for ducts of other than standard sheet-metal construe-