Localised fires commonly occur in large single-storey industrial halls where combustible materials are concentrated in limited areas. Nominal fire curves used in prescriptive design cannot represent the non-uniform thermal environment produced by such fires, particularly when flashover does not develop. This study applies performance-based fire design by integrating simplified localised fire models with two-zone modelling to more realistically estimate thermal actions on structural components. A 3D thermal-mechanical model of a steel industrial hall was developed in SAFIR, using thermal inputs from OZone, Hasemi and LOCAFI for a 50 MW, 8 m-diameter localised fire. Two strategies for applying the Hasemi model were examined: using the Eurocode H/10 height criterion and using the zone-interface height predicted by the two-zone model. Preliminary results show that the choice of height threshold influences column deformation and structural fire resistance, and that the H/10 limit may not always provide a sufficiently conservative boundary when hot-layer temperatures become dominant. A parametric study on opening factor and fire severity further highlights conditions under which two-zone modelling should supplement localised-fire analysis. The findings aim to support improved guidance on localised fires in future Eurocode developments.