Uncertainties in steel temperatures during fire

In order to determine the fire resistance of steel members, steel temperatures must be estimated with a high confidence. There can be considerable uncertainty in temperatures of both protected and unprotected steels during fire exposure. This is due to uncertainty in the thermal boundary conditions and thermophysical properties. In this study, uncertainties in both unprotected and protected steel temperatures are estimated with the use of a Monte Carlo method in conjunction with a “Lumped Heat Capacity” approach for estimating steel temperatures. Computed data are compared with experimental measurements obtained during Cardington fire tests (bare steel) and National Institute of Standards and Technology (NIST) World Trade Center (WTC) tests (protected). Reasonable agreement was achieved.