Steel Pipes and Heat Loss Diagram

Heat loss from steel pipes and tubes - dimensions ranging 1/2 - 12 inches

Heat loss from 1/2" to 12" steel pipes - at various temperature differences between pipes and surrounding air - are indicated in the diagram and table below:

heat loss diagram uninsulated steel pipes

  • 1 kW (kJ/s) = 102.0 kpm/s = 859.9 kcal/h = 3,413 Btu/h = 1.360 hk = 1.341 hp = 738 ft lb/s = 1,000 J/s = 3.6x106 J/h
  • 1 m (meter) = 3.2808 ft = 39.37 in = 1.0936 yd = 6.214x10-4 mile
Nominal boreHeat loss from Fluid inside Pipe (W/m)
Temperature Difference(oC)
(mm) (inch) 50 60 75 100 110 125 140 150 165 195 225 280
15 1/2 30 40 60 90 130 155 180 205 235 280 375 575
20 3/4 35 50 70 110 160 190 220 255 290 370 465 660
25 1 40 60 90 130 200 235 275 305 355 455 565 815
32 1 1/4 50 70 110 160 240 290 330 375 435 555 700 1000
40 1 1/2 55 80 120 180 270 320 375 420 485 625 790 1120
50 2 65 95 150 220 330 395 465 520 600 770 975 1390
65 2 1/2 80 120 170 260 390 465 540 615 715 910 1150 1650
80 3 100 140 210 300 470 560 650 740 860 1090 1380 1980
100 4 120 170 260 380 585 700 820 925 1065 1370 1740 2520
150 6 170 250 370 540 815 970 1130 1290 1470 1910 2430 3500
200 8 220 320 470 690 1040 1240 1440 1650 1900 2440 3100 4430
250 10 270 390 570 835 1250 1510 1750 1995 2300 2980 3780 5600
300 12 315 460 670 980 1470 1760 2060 2340 2690 3370 4430 6450

The heat loss value must be corrected by the correction factor for certain applications:

ApplicationCorrection factor
Single pipe freely exposed 1.1
More than one pipe freely exposed 1.0
More than one pipe along the ceiling 0.65
Single pipe along skirting or riser 1.0
More than one pipe along skirting or riser 0.90
Single pipe along ceiling 0.75

Related Topics

  • Heat Loss and Insulation - Heat loss from pipes, tubes and tanks - with and without insulation - foam, fiberglass, rockwool and more
  • Piping Systems - Dimensions of pipes and tubes - dimensions, materials, capacities - pressure drop calculations and charts - insulation and heat loss diagrams
  • Insulation - Heat transfer and heat loss from buildings and technical applications - insulation methods and coefficients to reduce energy consumption

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