Duct Installation Design Charts

Equivalent Resistance in ft.
 ø Elbow 90°  Elbow 90°2.5 CLR   Elbow 30° Branch
 3  2.5  1.75  2.0
  4   3.5 2.5 2.5
  5  4.5 3.25 3.5
  6  5.5 4.0 4.0
  7  6.5 5.0 5.0
  8  8.0 5.5 6.0
  9  9.0 6.5 7.0
 10  10.25 7.25 8.0
 11  11.5 8.0 9.0
 12  13.0 9.0 10.0
 13  14.5 10.0 11.0
 14  15.5 11.0 12.0
 16  18.5 13.0 14.0
 18  21.5 15.0 16.0
 20  24.0 17.0 18.0
 22  27.0 19.0 21.0
 24  30.0 21.0 23.0
 26  33.0 23.5 25.0
 28   37.0  25.5 27.0
 30  40.0 28.0 30.0
 32  43.0 30.0 32.0
 34   46.0  32.0 35.0
 36  49.0 35.0 37.0
 38  53.0 37.0 40.0
 40  56.0 40.0 42.0
 42  60.0 43.0  45.0
 44  64.0 45.0 47.0
 46  67.0 47.0 50.0
 48  70.0 49.0 53.0

Elbow Friction Factor Chart
 R. No. of Dia.  Loss Factor Elbow 30° Branch
1.0 D 0.33
1.5 D 0.24
 2.0 D 0.19
 2.5 D 0.17

 

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