User Guide

Plumbing Design Assistance Manual l Chapter 5 – System design and layout l 57
Uponor PEX vs. copper heat loss comparison — Btu/(hr•ft)
Delta T (°F) 20 40 60 80 100
Insulation
thickness
(K=0.24)
0" ½" 1" 1½" 0" ½" 1" 1½" 0" ½" 1" 1½" 0" ½" 1" 1½" 0" ½" 1" 1½"
Nominal pipe sizes
½"
Uponor PEX 5.44 2.22 1.63 1.37 10.89 4.44 3.25 2.74 16.33 6.65 4.88 4.10 21.78 8.87 6.51 5.47 27.22 11.09 8.13 6.84
Type L copper 5.76 2.24 1.63 1.37 11.52 4.47 3.27 2.74 17.27 6.71 4.90 4.11 23.03 8.95 6.53 5.48 28.79 11.18 8.16 6.85
¾"
Uponor PEX 7.48 2.73 1.95 1.61 14.96 5.47 3.89 3.21 22.44 8.20 5.84 4.82 29.92 10.94 7.78 6.43 37.40 13.67 9.73 8.03
Type L copper 8.06 2.77 1.96 1.61 16.12 5.54 3.91 3.22 24.18 8.31 5.87 4.84 32.25 11.07 7.83 6.45 40.31 13.84 9.78 8.06
1"
Uponor PEX 9.42 3.23 2.25 1.83 18.85 6.47 4.50 3.66 28.27 9.70 6.75 5.49 37.69 12.93 8.99 7.33 47.11 16.17 11.24 9.16
Type L copper 10.36 3.29 2.27 1.84 20.73 6.58 4.53 3.68 31.09 9.86 6.80 5.52 41.46 13.15 9.06 7.36 51.82 16.44 11.33 9.20
1¼"
Uponor PEX 11.29 3.72 2.54 2.05 22.58 7.44 5.08 4.09 33.87 11.16 7.63 6.14 45.16 14.88 10.17 8.19 56.45 18.60 12.71 10.24
Type L copper 12.67 3.80 2.57 2.06 25.34 7.60 5.14 4.12 38.00 11.40 7.70 6.18 50.67 15.20 10.27 8.24 63.34 19.00 12.84 10.30
1½"
Uponor PEX 13.08 4.20 2.83 2.26 26.15 8.40 5.66 4.51 39.23 12.60 8.49 6.77 52.30 16.79 11.31 9.03 65.38 20.99 14.14 11.28
Type L copper 14.97 4.31 2.86 2.27 29.94 8.61 5.73 4.55 44.91 12.92 8.59 6.82 59.89 17.23 11.45 9.10 74.86 21.53 14.32 11.37
2"
Uponor PEX 16.46 5.13 3.39 2.66 32.93 10.27 6.77 5.33 49.39 15.40 10.16 7.99 65.85 20.54 13.55 10.65 82.31 25.67 16.94 13.32
Type L copper 19.58 5.31 3.45 2.69 39.16 10.63 6.89 5.38 58.73 15.94 10.34 8.08 78.31 21.25 13.78 10.77 97.89 26.57 17.23 13.46
2½"
Uponor PEX 19.30 5.92 3.92 3.00 38.60 11.85 7.84 6.01 57.90 17.77 11.76 9.01 77.20 23.69 15.68 12.01 96.50 29.61 19.60 15.01
Type L copper 24.20 6.32 4.09 3.10 48.41 12.63 8.18 6.20 72.61 18.95 12.26 9.30 96.82 25.26 16.35 12.40 121.02 31.58 20.44 15.50
3"
Uponor PEX 22.54 6.94 4.47 3.44 45.07 13.88 8.93 6.89 67.61 20.82 13.40 10.33 90.14 27.76 17.86 13.77 112.68 34.70 22.33 17.22
Type L copper 28.79 7.31 4.59 3.50 57.58 14.62 9.17 7.01 86.37 21.93 13.76 10.51 115.16 29.24 18.35 14.01 143.95 36.55 22.93 17.51
Table 5-14: Uponor PEX vs. copper heat loss comparison — Btu/(hr•ft)
1. All calculations based on cylindrical thermal resistance methodology (ASPE/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.