Install Instructions

Fastening the Viega PureFlow System
67 of 88
IM-PF 724596 1021 PureFlow Water System (EN)
12.10 Calculating Expansion Loops and O󶈴sets
There are three types of expansion o󶈴sets recommended for use with
large-diameter tubing:
■ Corner expansion o󶈴set
■ Z-type expansion o󶈴set
■ U-type expansion loop
A description, illustration, and dimensions chart for each type of o󶈴set are
on the next few pages.
To calculate linear expansion for PEX tubing, use the following formula:
∆L =
PEX expansion rate
100' x 10° F
x ∆T x LT
Where:
Viega PureFlow PEX expansion rate = 1.1" per 100' per 10° F
∆T = Change in temperature (in ° F)
LT = Length of tube between 󶈵xed points (in ft.)
For example:
40' of 1" Viega PureFlow PEX tubing going from 70° F to 130° F
∆L =
1.1"
1000
x 60° x 40' = 2.64"
∆L = 2.64"
12.10.1 Linear Expansion
12.10.2 Compensation Distance
To calculate the dimensions of the expansion compensation o󶈴set
needed, use the following formula:
L = C√OD x ∆L
Where:
L = length of compensation distance
C = 12 (PEX material speci󶈵c constant)
OD = outer tubing diameter (⅛" + nominal tube size)
∆L = change in length from temperature change