Pipe Insulation Heat Loss Calculator
Calculate steady outward heat flow through cylindrical pipe insulation and outer convection, including signed heat gain and surface temperature.
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Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Add cylindrical insulation and outer convection resistances, apply the signed temperature difference and recover the outer surface temperature.
R=ln(ro/ri)/(2πkL)+1/(h2πroL); Q=(Tpipe−Tair)/R
Worked example
A 25 mm pipe radius with 25 mm insulation, k=0.04 W/(m·K), h=8 W/(m²·K), length 10 m and 60 K difference gives about 190.124167 W outward heat flow.
Assumptions and input details
Pipe surface is isothermal and the insulation is a uniform concentric cylindrical layer. A zero thickness gives the same conditional bare-pipe convection model. The bare comparison keeps h fixed; insulation can increase ideal loss near the cylindrical critical radius. Radiation, ends, fluid films, pipe-wall resistance, contact gaps and property variation are excluded. This does not certify insulation or burn protection.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
SI prefixes are explicit: for example, milli means one thousandth, micro one millionth and kilo one thousand. Changing a unit changes the interpretation of the entered number.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
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The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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