Fluid dynamics & thermodynamics · preliminary design

Pipe Insulation Heat Loss Calculator

Calculate the radial conductive heat loss through cylindrical pipe insulation.

ƒ≤ 5

Inputs

Insulation inner diameter [mm]Insulation thickness [mm]Conductivity λ [W/(mK)]Pipe length [m]Temperature difference [K]

Homogeneous-insulation conduction only; films, radiation, pipe wall, supports and moisture excluded.

Enter values and run the calculation.

Method

In radial conduction, area increases with radius. The diameter ratio therefore appears logarithmically in resistance.

Rλ = ln(da/di)/(2πλL)

Q̇ = ΔT/Rλ

Practice

Compare insulation thicknesses and estimate distribution losses.

Homogeneous-insulation conduction only; films, radiation, pipe wall, supports and moisture excluded.

FAQ

The entered difference is across insulation; fluid and air temperatures require extra film resistances.

No; cylindrical geometry makes the relation logarithmic.

Source

Dubbel, thermodynamics, heat transmission through pipes (local source, 2026-09-09).

The source supports the equation structure; this calculator does not claim a complete standards verification.