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Heat Loss Steam Pipes

Reference data and engineering information about heat loss steam pipes for heat transfer applications.

heatlosssteampipesCalculator

Overview

Engineering reference data for Heat Loss Steam Pipes in heat transfer.

Key Formulas

Fourier's Law

q=−k∇Tq = -k \nabla T

Heat flux proportional to temperature gradient.

Convective Heat Transfer

Q=hA(Ts−T∞)Q = hA(T_s - T_\infty)

Heat transfer between surface and fluid.

Stefan-Boltzmann Law

q=εσT4q = \varepsilon \sigma T^4

Radiative heat flux from a surface.

Thermal Resistance

Rth=LkAR_{th} = \frac{L}{kA}

Resistance to heat conduction.

Variables

SymbolDescriptionUnit
qqHeat fluxW/m²
kkThermal conductivityW/(m·K)
hhConvection coefficientW/(m²·K)
TTTemperatureK
ε\varepsilonEmissivity—
σ\sigmaStefan-Boltzmann constant5.67×10⁻⁸ W/(m²·K⁴)

Heat Loss Data for Bare Uninsulated Steam Pipes

The following data applies to horizontal bare uninsulated steam pipes in still air conditions with surrounding air temperatures ranging from 50°F to 70°F.

12 rows
Heat loss from bare uninsulated horizontal steam pipes in still air (Btu/h per ft of pipe)
Temperature Difference(°F)
1/2(Btu/h·ft)
3/4(Btu/h·ft)
1(Btu/h·ft)
1-1/4(Btu/h·ft)
1-1/2(Btu/h·ft)
2(Btu/h·ft)
2-1/2(Btu/h·ft)
3(Btu/h·ft)
4(Btu/h·ft)
6(Btu/h·ft)
100566882107113138163194243337
1207185104127142175206246308427
14086104127155173212251300375521
160103125152186213256301360451626
180121146176217243297351417522725
200139171206251282346408488622850
2251661992432973344104835787261009
2501922332843473894785636748491180
2752202663263984475506497789781360
30025130437245551062874288811401557
325285343425520580705843101012401730
350322388480590660790945113013581930

Source: engineeringtoolbox.com

Unit Conversion

To convert from Imperial to SI units:

1 Btu/h⋅ft=0.96 W/m1 \text{ Btu/h·ft} = 0.96 \text{ W/m}

Notes on Heat Loss Factors

The heat loss from steam pipes depends on several factors:

  • Pipe size — Larger diameter pipes have greater surface area and higher total heat loss
  • Insulation quality — Bare pipes lose significantly more heat than insulated pipes
  • Steam temperature/pressure — Higher temperature steam has greater temperature differential to surroundings
  • Ambient temperature — Greater temperature difference (ΔT) between steam and surrounding air increases heat loss rate
  • Air conditions — Still air vs. moving air affects convective heat transfer coefficients

Interactive Charts

Steam pipe - Heat loss from pipe to surrounding air chart

References

Source: engineeringtoolbox.com