Rehau Edge User Manual

6.7.3
Calculation of deflection leg length
The minimum length of deflection length (DL) is calculated
by the following formula:
L
DL
= Length of deflection leg
da = Outer pipe diameter in mm
ΔL = Length change in mm
C = Material contstant of piping material
For approximate values for material constant C,
see Table 6-4.
Do not fit pipe support channels or pipe brackets close to
the deflection legs so it will not be prevented from bending.
L
DL
Length of deflection leg
ΔL Thermal length change
L Pipe length
6.7.4 Calculation examples
The pipe length L, for which the thermal length changes is
to be accommodated at a deflection length, is 7m.
The temperature di
erence between the minimum and
maximum
v
alues (installation
temper
atur
e and subsequen
t
operating
temper
ature) is 50 °C. The installed pipe outer
diameter is 25mm.
What length of deflection leg is required according to the
installed pipe type?
Calculation of deflection leg length with EDGE
TM
pipe
ΔL = α • L • ΔT
ΔL = 0.04 • 7m • 50ºC
ΔL = 14 mm
L
DL
= C • √d
a
• ΔL
L
DL
= 12 • √25mm • 14 mm
L
DL
= 224 mm
For metallic pipe materials, a substantially larger deflection
leg is required for the same operating parameters during
installation, due to the significantly higher material
constant (C), than for EDGE
TM
pipes system.
L
DL
L
/
2
/
2
/
2
/
2
1
/
2
L
DL
x
G
G
F
F
F
L
DL
= C  d
a
 L
Fig. 6-13 U expansion bends
24

Rehau Edge Specifications

General

Brand	Rehau
Model	Edge
Category	Construction Equipment
Language	English