Installation Guide

FlowGuard Gold
®
JANUARY 2013
7
OTHER DESIGN CRITERIA
THERMAL EXPANSION
CPVC systems, like all piping materials, expand
and contract with changes in temperature. The
coefficient of linear expansion is: 0.0000340
inch/inch-°F. FlowGuard Gold
®
pipe will expand
four (4) inches per 100 feet of length with a
100°F temperature change. Expansion does not
vary with pipe size. Expansion is only of concern
on hot water lines. The stresses developed in
CPVC are generally much smaller than those
developed in metal systems for equal temperature
changes because of significant differences in
elastic modulus. Therefore, expansion loop
requirements are not significantly different than
those recommended for copper pipe. Thermal
expansion can generally be accommodated at
changes in direction. On a long straight run, an
offset or loop based on the following chart is
required.
EXPANSION LOOP LENGTH (L)
IN INCHES FOR 100°F TEMPERATURE CHANGE
LENGTH OF RUN IN FEET
NOMINAL
SIZE
40 60 80 100
1/2" 24 30 34 39
3/4" 29 35 41 46
1" 33 40 46 52
1-1/4" 36 44 51 57
1-1/2" 39 48 56 62
2" 45 55 64 71
For design of expansion loops where the
anticipated temperature change (∆T) is more or
less than 100°F, the following factors can be
applied to the table above. The correct factor
should be chosen corresponding to the anticipated
temperature change (∆T), and multiplied by the
value of L at ∆T=100°F to determine the value of
L at other values of ∆T e.g. from previous
example:
L=30" @ ∆T=100°F. At ∆T=50°F, L=30" x 0.71=21".
CORRECTION FACTOR FOR EXPANSION LOOP
LENGTH TABLE FOR ANTICIPATED TEMPERATURE
CHANGE (∆T) OTHER THAN 100°F
TEMP
CHANGE
∆T (°F)
CORRECTION
FACTOR
TEMP
CHANGE
∆T (°F)
CORRECTION
FACTOR
50°F 0.71 110°F 1.05
70°F 0.84 130°F 1.14
90°F 0.95 150°F 1.22
THERMAL CONDUCTIVITY
CPVC Material: 0.95 BTU/HR-Ft2.°F/in *
*Note: This is the heat transfer per hour through
a one foot square by one inch thick piece of
CPVC. It is not the conductivity of the pipe,
which varies by size.
Example: Pipe Size – 1/2" Length of Run – 60' L=30" (from table)