User Guide

184 l uponorengineering.com
1. All calculations based on cylindrical thermal resistance methodology (ASHRAE).
2. Based on uid velocity of 8 ft./sec. at 160°F/71.1°C (maximizing heat transfer from 100% water).
3. Pipe convection set to be 1.761 Btu/hr•ft²•°F (based on standard value for free convection of air).
4. This heat loss comparison uses 0.24 Btu•in/(hr•ft2•°F) as the insulation thermal conductivity.
This is a standard value for berglass pipe insulation at a 100°F/37.8°C mean temperature.
Pipe heat loss and surface temperature
3" Uponor PEX surface
temperature at 90°F/32.2°C ambient
Water
temp
(ºF)
Surface temperature (°F)
No insulation
½" insulation
1" insulation
1½" insulation
2" insulation
30 38.7 72.9 80.6 83.7 85.4
40 47.3 75.8 82.1 84.8 86.2
50 55.8 78.6 83.7 85.8 87.0
60 64.4 81.5 85.3 86.9 87.7
70 72.9 84.3 86.9 87.9 88.5
80 81.5 87.2 88.4 89.0 89.2
90 90.0 90.0 90.0 90.0 90.0
100 98.5 92.8 91.6 91.0 90.8
110 107.1 95.7 93.1 92.1 91.5
120 115.6 98.5 94.7 93.1 92.3
130 124.2 101.4 96.3 94.2 93.0
140 132.7 104.2 97.9 95.2 93.8
150 141.3 107.1 99.4 96.3 94.6
160 149.8 109.9 101.0 97.3 95.3
170 158.3 112.8 102.6 98.4 96.1
180 166.9 115.6 104.2 99.4 96.9
190 175.4 118.4 105.7 100.4 97.6
200 184.0 121.3 107.3 101.5 98.4
3" Uponor PEX-a heat loss
at 90°F/32.2°C ambient
Water
temp
(ºF)
Heat loss (btu/hr·ft)
No insulation
½" insulation
1" insulation
1½" insulation
2" insulation
30 -41.9 -18.4 -12.7 -10.0 -8.5
40 -34.9 -15.4 -10.6 -8.4 -7.1
50 -28.0 -12.3 -8.5 -6.7 -5.7
60 -21.0 -9.2 -6.3 -5.0 -4.3
70 -14.0 -6.1 -4.2 -3.3 -2.8
80 -7.0 -3.1 -2.1 -1.7 -1.4
90 0.0 0.0 0.0 0.0 0.0
100 7.0 3.1 2.1 1.7 1.4
110 14.0 6.1 4.2 3.3 2.8
120 21.0 9.2 6.3 5.0 4.3
130 28.0 12.3 8.5 6.7 5.7
140 34.9 15.4 10.6 8.4 7.1
150 41.9 18.4 12.7 10.0 8.5
160 48.9 21.5 14.8 11.7 9.9
170 55.9 24.6 16.9 13.4 11.4
180 62.9 27.6 19.0 15.1 12.8
190 69.9 30.7 21.1 16.7 14.2
200 76.9 33.8 23.2 18.4 15.6