6
Installation & Commissioning Instructions
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Gerpex Press Fit System
Gerpex Press Fit System
2.5 Thermal Expansion
For surface mounted installation or when installed in
shafts, voids etc, longitudinal thermal expansion can
be compensated for with consideration of fixed and
sliding brackets depending on type of installation.
These sliding brackets allow the pipe to expand and
contract without sagging and/or putting any undue
stress on the pipe and brackets. Please see Fig 2.6,
2.7 and 2.8 for example:
Where:
Ls = C x √ (Ø x ΔL)
Ls = Length of compensator (mm)
Ø = External diameter of pipe (mm)
C = Material constant
(for insulated pipes C=33)
With
ΔL = 15.6 mm (previous example),
Ø = 26 mm
the result will be:
Ls = 33 x √ (26 x 15.6) = 665 mm
FP
FP
FP
L
L
∆
L
∆
L
FP
SP
SP
L
FP
SP
∆
L
∆
L
Ls
Ls
To allow expansion for pipes installed vertically in
shafts or risers with horizontal branches, the branch
must have a minimum free length (LS) and the
transition through the wall of the shaft should not
be sealed so as to allow for movement and the pipe
should also be sleeved. See Fig 2.9 and 3.0.
If the size of the shaft does not allow for the
compensation length (LS) the transitional hole in the
wall of the shaft should be increased in diameter
and the tube should be protected with an insulating
sheath of thickness; see Fig 3.1.
Where pipes are being laid within screeded floors
thermal expansion can be allowed for by creating an
insulated curve at 10m intervals. This can be done
by enclosing within insulation or flexible conduit, see
Fig 3.2.
Note: If the pipe is being used for underfloor heating
and is using spiral or serpentine loops this method
need not apply.
2. Installation
FP: Fixed Point
SP: Sliding Point
Fig 2.6
Fig 2.7
Fig 2.8
Fig 2.9
Fig 3.0
Fig 3.1
Fig 3.2
