User Guide

Installing PureFlow Systems
47
PG-PF 724998 0320 PureFlow System
U-Type Expansion O󶈴set
The U-type expansion loop integrates
four 90° elbows that form a “U” pattern.
Looped Offset
L3
L4L4
4 - 6" 4 - 6"
∆L/2 ∆L/2
LT
Anchor point Anchor point
U-Type Looped Offset
L4 = 8.28"
L3 = 4.14"
L4 = 8.28"
U-Type Expansion
FostaPEX
FostaPEX tubing has a fully dimensional
PEX wall with an additional outer layer of
aluminum and polyethylene. As a result
of these extra layers, FostaPEX expands
considerably less than that of standard
PEX tubing and slightly more than copper
tubing (0.16" per 100 feet per 10°F).
An approved method for expansion
absorption when using FostaPEX
is through the use of a coiled loop
expansion compensator (at least every
50 feet). Do not use 󶈵tting o󶈴sets with
FostaPEX as the sti󶈴ness of FostaPEX
may lead to high stress at connections.
Coiled Loop
The coiled loop con󶈵guration calls for loops
within the piping system. The diameter of
the loop (D) is shown in the table and will
increase or decrease as the tubing in the
system expands and contracts.
Note: Tubing fasteners should be
secured as to not prevent linear
movement of tubing.
D
Coiled Loop Expansion
Coiled Loop Expansion
Tube Nominal Size D (Diameter)
½" FostaPEX 12"
⅝" FostaPEX 14"
¾" FostaPEX 16"
1" FostaPEX 20"
See the PureFlow Water System Installation
Manual or the PureFlow Commercial Water
System Design Manual for details on how to do
calculations.