Timber Charring Rate Calculator

Calculate timber charring rate and residual cross-section for fire-exposed wood members per Eurocode EN 1995-1-2 and NDS

Input Parameters

Results

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Char Depth
mm
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Residual Width
mm
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Residual Depth
mm
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Residual Area Ratio
%
Note: The reduced cross-section method assumes charred wood has zero strength while the residual section retains full ambient-temperature properties. The 7mm zero-strength layer accounts for heated but uncharred wood with reduced strength.

Reference

Eurocode EN 1995-1-2 / NDS Chapter 16 Char depth: d_char = beta_n * t Effective depth: d_eff = d_char + d_0 (d_0 = 7mm zero-strength layer) Softwood beta_n = 0.65 mm/min Hardwood beta_n = 0.50 mm/min Glulam beta_n = 0.70 mm/min Residual section retains full ambient strength