Install Instructions

Fastening the Viega PureFlow System
66 of 88
IM-PF 724596 1021 PureFlow Water System (EN)
12.9 Tubing Expansion
Viega PureFlow PEX tubing, as with any PEX tubing, expands and
contracts with temperature changes in the environment or the 󶈶uid inside
the tubing. The longer the tubing run and the higher the temperature
change, the more linear expansion the system will experience. This
expansion and contraction can a󶈴ect the appearance as well as integrity
of the system by putting stress on the tubing, 󶈵ttings, valves, and
fasteners. The system should be designed to accommodate tubing
expansion.
Tubing fasteners perform two functions: providing support for the tubing
and guiding the tubing during expansion and contraction. It is important
to keep this in mind when installing fasteners. An expansion compensator
will not be e󶈴ective if the fasteners prevent linear movement of the piping
system.
Tubing sizes smaller than ¾" generally do not require expansion
compensators with 󶈵ttings and can easily be bent into loops and
o󶈴sets to absorb linear expansion. For tubing sizes 1" and larger, refer
to "12.10 Calculating Expansion Loops and O󶈴sets" on page 67 for
compensation options.
For unconstrained tubing runs (not within the 󶈶oor) Viega recommends
the use of expansion o󶈴sets. This can be accomplished at a corner or by
using o󶈴sets or loops on straight tubing runs. Expansion compensators
should be installed at the midway point of tubing runs and should be
spaced no more than 50 feet apart.
Below is an example of required o󶈴sets for a 100-foot tubing run. Note
that the expansion compensators are no more than 50 feet apart.
Using a loop to
accommodate
tubing expansion
O󶈴sets also provide
room for tubing
expansion.
Allow some slack in all runs to prevent
damage from tubing contraction.
⅛" to
3
/
16
"
slack per foot
100'
25'25' 50'
50' 50'