OhMyCalc

Chimney Section Calculator

Compute the required chimney cross-section and round-duct diameter for a boiler, by rated power and fuel type (solid / gas).

How to Use the Chimney Section Calculator

  1. Enter boiler rated power in kW.
  2. Pick fuel type.
  3. Click Calculate to get section and diameter.

Anwendungsfälle

Formel

F (cm²) = K · P (kW), where K = 5.5 for solid fuel and 4 for gas. Diameter (mm) = 2·√(F/π) × 10.

Häufig gestellte Fragen

Where does K come from?
Empirical coefficients from SP 7.13130.2013 and DIN EN 13384: solid-fuel boilers need a larger section because of higher flue-gas volume.
Is this enough to design a chimney?
No — it is a first sizing estimate. Final design must account for height, temperature, insulation and draft per EN 13384 / SP 7.13130.