User Guide

168 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 50°F/10°C ambient
Water
temp
(ºF)
Surface temperature (°F)
No insulation
½" insulation
1" insulation
1½" insulation
2" insulation
30 32.9 44.3 46.9 47.9 48.5
40 41.5 47.2 48.4 49.0 49.2
50 50.0 50.0 50.0 50.0 50.0
60 58.5 52.8 51.6 51.0 50.8
70 67.1 55.7 53.1 52.1 51.5
80 75.6 58.5 54.7 53.1 52.3
90 84.2 61.4 56.3 54.2 53.0
100 92.7 64.2 57.9 55.2 53.8
110 101.3 67.1 59.4 56.3 54.6
120 109.8 69.9 61.0 57.3 55.3
130 118.3 72.8 62.6 58.4 56.1
140 126.9 75.6 64.2 59.4 56.9
150 135.4 78.4 65.7 60.4 57.6
160 144.0 81.3 67.3 61.5 58.4
170 152.5 84.1 68.9 62.5 59.1
180 161.0 87.0 70.5 63.6 59.9
190 169.6 89.8 72.0 64.6 60.7
200 178.1 92.7 73.6 65.7 61.4
3" Uponor PEX heat loss
at 50°F/10°C ambient
Water
temp
(ºF)
Heat loss (btu/hr·ft)
No insulation
½" insulation
1" insulation
1½" insulation
2" insulation
30 -14.0 -6.1 -4.2 -3.3 -2.8
40 -7.0 -3.1 -2.1 -1.7 -1.4
50 0.0 0.0 0.0 0.0 0.0
60 7.0 3.1 2.1 1.7 1.4
70 14.0 6.1 4.2 3.3 2.8
80 21.0 9.2 6.3 5.0 4.3
90 28.0 12.3 8.5 6.7 5.7
100 34.9 15.4 10.6 8.4 7.1
110 41.9 18.4 12.7 10.0 8.5
120 48.9 21.5 14.8 11.7 9.9
130 55.9 24.6 16.9 13.4 11.4
140 62.9 27.6 19.0 15.1 12.8
150 69.9 30.7 21.1 16.7 14.2
160 76.9 33.8 23.2 18.4 15.6
170 83.9 36.9 25.4 20.1 17.0
180 90.8 39.9 27.5 21.8 18.5
190 97.8 43.0 29.6 23.4 19.9
200 104.8 46.1 31.7 25.1 21.3