Technical data

29
Compressed Air Applications Manual | Dimensioning Compressed Air Applications Manual | Dimensioning
Pipe system dimensioning
The network layout determines the length
of the main pipe, distribution pipes and
connecting pipes. Pipe fittings (elbows,
T-pieces, etc.) and valves must be added
to the length of the line according to their
equivalent pipe length value.
The initial dimensioning of the pipe sys-
tem can be carried out on the basis of
Table 1. For the maximum flow rates of
the different pipe diameters at different
operating pressures it is assumed that
the pressure loss will be 0.03 bar over a
pipe length of 100 m.
Table 1
Operating
pressure
(bar)
4 6 8 10 12 16
Pipe
diameter Max. flow rate (m
3
/min)
d 16 – – – – 1.10 0.15
d 20 – – – 0.18 0.20 0.25
d 25 0.20 0.28 0.30 0.34 0.38 0.45
d 32 0.48 0.55 0.62 0.70 0.75 0.85
d 40 0.78 0.90 1.00 1.30 1.50 1.70
d 50 1.40 1.75 2.00 2.20 2.60 3.00
d 63 2.50 3.25 3.80 4.20 4.60 5.20
d 75 4.10 5.00 6.00 7.00 7.50 8.20
d 90 7.00 8.10 9.95 11.00 12.50 14.00
d 110 11.50 14.00 16.00 18.00 20.00 20.00
Pipe length L = 100 m
Pressure loss ∆p = 0.03 bar
1 m
3
/min = 1 000 l/min = 16.7 l/s
Example:
DP = 110 m
∆p = 0.03 bar
p = 6.0 bar
V = 4 500 l/min
Distribution pipe d 75 L = 110 m
1 T-piece 2.5 m
4 Elbows 90
0
6.0 m
3 Ball valves approx. 1.6 m
Total lenght 120.1 m
For an operating pressure of 6 bar and a
compressed air demand of 4,500 l/min
(4.5 m³/min) Table 1 indicates a pipe
diameter of
d 75.
The initial pipe dimensioning can also be
calculated with the following approxima-
tion:
5
1.6 x 10
3
x V
1.85
x L
DN =
∆p x p
The allowances for fittings and valves are
set out in Table 2 (see p. 31).
DN = nominal pipe
diameter (m)
L = pipe length (m)
V = vol. flow rate (m
3
/s)
∆p = pressure loss (Pa)
p = network pressure (Pa)
1 bar = 10
5
Pa