Thermal behaviour of a steel door frame subjected to the standard fire of ISO 834: Measurements, numerical simulation and parameter study

An adjustable steel frame of a steel door, built in a massive brick wall, was subjected to fire according to the international standard ISO 834. Additional thermocouples, with respect to the ones required by the standard, were positioned at different sites of the steel frame cross-section to validate the numerical analysis carried out to study its thermal insulation performance. The leaf/frame interaction was monitored during the fire test to verify the integrity criterion, but was neglected in the calculations by assuming adiabatic conditions at the door clearance. Based on these findings, a parametric study was conducted to investigate the influence of boundary conditions, empty or filled frame cavities, and adjustable versus wrap-around frame on the temperature distribution of the steel frame. Combining the results of fire test and numerical simulation, the possibility to mutually assert the thermal performance, i.e. the insulation criterion for the cases of opening into and opening away from furnace, is discussed.