Concrete Cover Fire Rating Calculator

Determine minimum concrete cover to reinforcement for required fire resistance rating per ACI 216.1/TMS 216 and Eurocode EN 1992-1-2

Input Parameters

Results

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Minimum Cover
mm
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Minimum Width
mm
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Depth to 500C Isotherm
mm
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Capacity Retention
%
Note: Cover requirements ensure reinforcing steel stays below critical temperature (approximately 500C for strength retention). Carbonate and lightweight aggregates have better fire performance due to calcination and lower thermal conductivity.

Reference

ACI 216.1 / Eurocode EN 1992-1-2 Minimum cover per ACI 216.1 Table 4.3.1 Minimum member width per ACI 216.1 Table 4.2.1 500C isotherm method: rebar above 500C loses significant strength Carbonate aggregates perform ~10% better than siliceous Lightweight aggregates provide ~15% better fire resistance