Book - School of Science and Technology

Pressure distribution in ducts 453AC(f)(g)WH(a)(b)(c)BSquare orcircular(h)(j)WRθ(d)(e)(k)(l)(m)(n) (p) (q) (r) (s) (t) (u) (v) (w) (x) (y)Bends Junctions TransitionsKey θ°(a)HW90 0.250.51.04.060 0.250.51.04.030 0.250.51.04.0(b) 90 all(c)906030(d) 90(e) 90circcirccircR0.5W W0.350.290.240.210.280.230.190.160.180.150.120.10single*double*0.240.190.110.370.390.330.270.210.180.260.220.170.140.170.140.110.090.240.430.220.170.100.270.24R = 0.05W1TV 2TV(a) 90withturningvanes(TV)0.250.51.02.04.00.520.400.430.550.750.260.200.220.280.37For bends in series refer to GuideSection C4.*Single or double skin turning vanesKey(f)(g)(h)(j)Type VC/VAor V B/VADiv. 0.5Con. 0.5Div. 0.40.60.9Con. 0.40.60.9Div.Con.Div.0.40.60.90.40.60.80.40.60.80.40.60.8(k) Div. 0.40.60.8(l)(m)Con.Con.Div.(45°)Con.(45°)Div.Con.0.300.230.410.681.6000.41.90.660.861.170.281.031.931.131.481.880.71.5~2.40.740.620.52ζC0.300.230.040.130.7200.651.20.02000.220.290.270.02000.610.500.340.0200No data available0.40.60.80.40.60.80.40.60.80.40.60.8ζB0.400.530.920.251.072.251.21.52.10.421.151.90.020000.050.120.02000.630.470.28The above factors for junctions arebased upon an area ratio of branchto main duct of 0.5. For other ratiosrefer to Guide Section C4.Div. = Diverging; Con. = ConvergingKey(p)VCVA(q) All –(n)EntriesKey(s)(t)0.20.40.60.20.350.50.650.8AAAC1.21.52.02.5θ°10 30 500.20.110.050.65Key0.420.250.120.04 (r)0.250.170.120.120.520.290.130.020.320.230.210.2VAVC0.250.50.70.650.360.160.070.370.230.09θ°60 90 1200.40.350.310.30.5 (u) 0.5 (v) 0.95Exits & Louvres (50% free area)(w) 1.0 (x) 6.0 (y) 3.0Noteζ apply to velocity insmaller areaFigure 16.17 Velocity pressure loss factors for ducting fittings