15
®
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Heat
Fixed Point F1
(L)
Expansion (∆L)
D=Minimum distance to fixed point F2
Fixed Point F2
Quick Reference Table - Corner Offset
Length of D for 50ft of PEX
∆T
(°F)
PEX Size
1⁄2"
3⁄4"
1"
11⁄4"
11⁄2"
2"
20
9.9"
11.8"
13.3"
14.8"
16.0"
18.3"
40
14.1"
16.6"
18.9"
20.9"
22.7"
25.9"
60
17.2"
20.4"
23.1"
25.6"
27.8"
31.8"
80
19.9"
23.5"
26.7"
29.5"
32.1"
36.7"
100
22.2"
26.3"
29.8"
33.0"
35.9"
41.0"
120
24.4"
28.8"
32.7"
36.1"
39.3"
44.9"
140
26.3"
31.1"
35.3"
39.0"
42.4"
48.5"
160
28.1"
33.3"
37.8"
41.7"
45.4"
51.9"
180
29.8"
35.3"
40.0"
44.3"
48.1"
55.0"
200
31.5"
37.2"
42.2"
46.7"
50.7"
58.0"
Common ∆T Range
Calculation for a 50 ft run of 1¼" PEX and temperature from 70°F to 150°F:
D = 12 × √ (1.25" + 0.125") × (50 ft × 1.1"/10°F/100ft × (150°F - 70°F)
D = 12 × √ 1.375" × (50 ft × 1.1"/10°F/100ft × 80°F)
D = 12 × √ 1.375" × 4.4"
D = 29.5"
Corner Offset
Example 1:
A 50ft straight run of 1¼" PEX is anchored at one end, and an elbow is installed
at the other end. It is a DHW supply pipe with an operating temperature of 150°F, but was
originally installed at 70°F, giving us a difference of 80°F, which equals 4.4" of expansion. In
this case a corner offset is the best solution.
L is the PEX length from the fixed (anchor) point (F1) to the elbow.
D is the minimum distance, measured from the elbow, to fixed point F2.
