ACO Pipe

Project Planning - Hydraulic Design

Compared to cast iron, clay and vitreouspipe systems, stainless steel pipes havea considerably smoother bore (ManningCoefficient: 0.011) and in general, areless susceptible to internal scaling.

In some instances, low roughness coefficients (ks) are not generally a true reflection of the long-term hydraulic performance of the installed system.Roughness coefficients of 0.6mm should be used for rainwater/storm drainage and 1.5mm for soil/foul drainage.

 

 

Flow Tables

Two sets of flow tables are presentedwithin this design guide.

Table 1 is for pipes installed with level (or nearly level) gradients where the steady,uniform flow equations are not applicable.The data therefore has been generated from ACO's hydraulic design program'Hydro' that is based on the equations of spatially-varied flow.

Table 2 is for pipes installed with varying gradients. The data is based on the Colebrook-White equation using an appropriate roughness coefficient for stainless steel.

When draining storm or foul water, it is inevitable that sediment deposits will occur within the drainage system.

Sediment and scale deposits will reduce the flow rate through any pipe system and it is recommended that an allowance is made for this within the design and planning phase.

 

 

Flow rates based on a spatially-varied flow formula for steady non-uniform flow. Manning Coefficient 0.011

 

Pipe Dia (mm)Length (m)0.0% Q (l/s)Gradient 0.25% Q (l/s)Gradient 0.5% Q (l/s)Gradient 0.75% Q (l/s)
50 5 0.40 0.57 0.75 0.92
50 10 0.30 0.54 0.75 0.92
50 15 0.26 0.53 0.75 0.92
50 20 0.23 0.53 0.75 0.92
75 5 1.45 1.75 2.40 2.90
75 10 1.10 1.72 2.35 2.90
75 15 0.95 1.70 2.35 2.90
75 20 0.85 1.70 2.35 2.90
110 5 4.50 5.55 6.75 8.15
110 10 3.60 5.05 6.60 8.15
110 15 3.20 4.90 6.50 8.15
110 20 2.80 4.80 6.50 8.15
125 5 6.45 7.90 9.60 11.45
125 10 5.20 7.25 9.50 11.45
125 15 4.55 7.00 9.50 11.45
125 20 4.10 6.85 9.50 11.45
160 5 13.00 15.40 18.60 21.20
160 10 10.90 14.30 18.50 21.20
160 15 9.50 13.80 18.40 21.20
160 20 8.50 13.50 18.30 21.20
200 5 24.80 29.00 34.20 38.70
200 10 20.80 26.70 33.80 38.40
200 15 18.60 25.70 33.70 38.40
200 20 17.00 25.00 33.60 38.40

 

Using spatially varied flow equations, the length to an outlet will determine the maximum flow rate through the pipe. The flow rates

shown above assume an unrestricted discharge from the pipe. For installations without an unrestricted discharge, the flow rate will be

affected by the downstream throttle.

Table 2a. For rainwater/storm drainage applications

Flow rates based on a Colebrook-White formula. Roughness coefficient ks =0.6mm 

 

Gradient
(%)
Pipe Ø50mm
Q(l/s) v(m/s)
Pipe Ø75mm
Q(l/s) v(m/s)
Pipe Ø110mm
Q(l/s) v(m/s)
Pipe Ø125mm
Q(l/s) v(m/s)
Pipe Ø160mm
Q(l/s) v(m/s)
Pipe Ø200mm
Q(l/s) v(m/s)
10.0 2.74   1.52 8.40   2.01 23.81  2.60 33.61  2.83 64.15   3.31 116.89  3.83
7.5 2.38   1.31 7.28   1.74 20.62   2.25 29.11  2.45 55.56   2.87 101.22  3.32
5.0 1.94   1.07 5.94   1.42 16.83  1.84 23.77  2.00 45.36    2.34 82.65   2.71
4.5 1.84   1.02 5.64   1.35 15.97  1.74 22.55   1.90 43.03  2.22 78.40  2.57
4.0 1.73   0.96 5.31   1.27 15.06  1.64 21.26  1.79 40.57    2.10 73.92  2.43
3.5 1.62   0.90 4.97   1.19 14.08  1.54 19.88  1.67 37.95   1.96 69.14  2.27
3.0 1.50   0.83 4.60   1.10 13.04  1.42 18.41  1.55 35.13   1.81 64.01  2.10
2.5 1.37   0.76 4.20   1.00 11.90  1.30 16.80  1.41 32.07   1.66 58.43  1.92
2.0 1.23   0.68 3.76   0.90 10.64  1.16 15.03  1.26 28.68   1.48 52.26 1.71
1.5 1.06   0.59 3.25   0.78 9.22  1.01 13.01  1.10 24.84   1.28 45.26 1.48
1.0 0.87   0.48 2.66   0.63 7.53  0.82 10.63  0.89 20.28  1.05 36.95  1.21

 

Table 2b. For soil/foul water drainage applications

Flow rates based on a Colebrook-White formula. Roughness coefficient ks =1.5mm

Gradient
(%)
Pipe Ø50mm
Q(l/s) v(m/s)
Pipe Ø75mm
Q(l/s) v(m/s)
Pipe Ø110mm
Q(l/s) v(m/s)
Pipe Ø125mm
Q(l/s) v(m/s)
Pipe Ø160mm
Q(l/s) v(m/s)
Pipe Ø200mm
Q(l/s) v(m/s)
10.0 2.30   1.27 7.14   1.71 20.45   2.23 28.97   2.44 55.61   2.87 101.81   3.34
7.5 1.99   1.10 6.19   1.48 17.71   1.93 25.09   2.11 48.16   2.49 88.17   2.89
5.0 1.6   0.80 4.52   1.08 12.94   1.41 18.32   1.54 35.17   1.82 64.39   2.11
3.5 1.36   0.75 4.23   1.01 12.10   1.32 17.14   1.44 32.90   1.70 60.23   1.98
3.0 1.26   0.70 3.91   0.93 11.20  1.22 15.87   1.34 30.46   1.57 55.76   1.83
2.5 1.15   0.64 3.57    0.85 10.23   1.12 14.49   1.22 27.80   1.44 50.90   1.67
2.0 1.03   0.57 3.19   0.76 9.15   1.00 12.96    1.09 24.87   1.28 45.53   1.49
1.5 0.89   0.49 2.77    0.66 7.92   0.86 11.22   0.94 21.53   1.11 39.43   1.29
1.0 0.73   0.40 2.26   0.54 6.47   0.71 9.16   0.77 17.58   0.91 32.19   1.06

 

The flow rates shown above assume an unrestricted discharge from the pipe. For installations without an unrestricted discharge, the flow rate will be affected by the downstream throttle. For shallow gradients, the Colebrook-White formula underestimates flow rates (because when gradient tends towards zero%, velocity also tends to zero). For level (or nearly level) installations (slope < 1%), spatially varied flow tables should be used; refer to Table 1.