Rehau Edge User Manual

The ∆L value resulting from this equation is the change
in length of a pipe due to thermal expansion. Excessive
length changes may cause potential stress on joints in
the system. The eects of this stress can be mitigated by
using deflection legs. EDGE
TM
PE-Xa pipes are particularly
suitable for this due to their flexibility.
The coeicient of linear thermal expansion must be
selected according to the installed pipe type and if pipe
support channel is installed.
Determining the pipe length
The pipe length L is the actual installed pipe length on
site between anchor points, expansion bends or loops.
Sometimes it may be necessary to divide the pipe run into
several sections by adding anchor points or expansion
bends and loops to limit the change in length per section.
Determining the temperature ∆T
To determine the temperature dierence , the following
shall be taken into consideration:
• Installation temperature or minimum operationg
temperature (e.g. when the system is out of
service)
• Maximum operating temperature (e.g. thermal
disinfection)
6.7
Provision for thermal expansion
6.7.1
Calculating thermal length changes
Due to the changing operational temperatures, especially
in hot water pipes, any pipe material will undergo thermal
expansion. This thermal expansion needs to be managed in
a safe way to avoid tension in unwanted locations along
the pipe length.
Any fixed points that restrict the free expansion and
contraction of the pipe must be avoided. Such fixed points
may inadvertently be created when fittings are installed
close to penetrations in walls, floors, joists or other fixed
building elements.
Make sure that the piping has suicient scope for
movement (e.g. from deflection legs).
The thermal change in pipe length is calculated with the
following equation:
ΔL = α • L • ΔT
L = Length change in mm
α = Coeicient of linear thermal expansion
in
L = Length of piping in m
T = Temperature dierence in ºC
Tab.6-4 Coeicient of linear thermal expansion (approximate values) and material constants for deflection leg calculation (approximate values)
Pipe type Pipe size Coefficient of linear thermal
expansion α [ ]
Material constant C
ΔL = α • L • ΔT
L
DL
= C • √d
a
• ΔL
16-32 without REHAU support channel
. 
16-32 with REHAU support channel
. 
EDGE Silver
EDGE Green
EDGE Red
EDGE Lilac
22

Rehau Edge Specifications

General

Brand	Rehau
Model	Edge
Category	Construction Equipment
Language	English