PEX Installation Manual
Table Of Contents
- 1 Introduction
- 2 Codes, Standards and Certifications
- 3 Viega PEX Installation Methods
- 4 Viega Manifolds
- 5 Viega PEX Press Fittings
- 6 Viega PEX Crimp Fittings
- 7 ViegaPEX Ultra Tubing
- 8 Viega FostaPEX Tubing
- 9 Viega PEX System Design and Sizing
- 10 System Sizing and Calculations
- 11 Water Service Installation
- 12 Installing the ManaBloc
- 13 Mounting the ManaBloc
- 14 Installing Manifold Distribution Lines
- 15 Installing the ViegaPEX Ultra Tubing System
- 16 Fastening the Viega PEX System
- 17 Installing Viega PEX Fittings
- 18 Pressure Testing Viega PEX Systems
- 19 System Disinfection
- 20 Warranty
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IM-PF 724596 0416
Using a loop to accommodate
tubing expansion
Offsets also provide room for
tubing expansion.
Allow some slack in all runs to prevent
damage from tubing contraction.
Below is an example of required offsets for a 100-foot
tubing run. Note that the expansion compensators are
no more than 50 feet apart.
100'
25'25' 50'
50' 50'
∆L =
PEX expansion rate
100' x 10°F
x ∆T x LT
Where:
ViegaPEX Ultra expansion rate = 1.1" per 100' per
10°F
∆T = Change in temperature (in °F)
LT = Length of tube between fixed points (in ft.)
∆L =
1.1"
1000
x 60° x 40' = 2.64"
∆L = 2.64"
For example:
40' of 1" ViegaPEX Ultra tubing going from 70°F to
130°F
16.9.1 Calculating expansion loops and offsets
There are three types of expansion offsets
recommended for use with large-diameter tubing:
the corner expansion offset, the Z-type expansion
offset and the U-type expansion loop. A description,
illustration and dimensions chart for each type of
offset is on the next few pages. See “FostaPEX” on
Page 53 for FostaPEX recommendations.
Linear expansion:
To calculate linear expansion for PEX tubing, use
the following formula:
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 effective if the fasteners
prevent linear movement of the piping system.
Tubing sizes smaller than ¾" generally do not
require expansion compensators with fittings and
can easily be bent into loops and offsets to absorb
linear expansion. Tubing sizes 1" and larger, refer
to “16.9.1 Calculating expansion loops and offsets”
for compensation options.
For unconstrained tubing runs (not within the floor)
Viega recommends the use of expansion offsets.
This can be accomplished at a corner or by using
offsets 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.
⅛" to
3
/
16
"
slack per foot