Modelling the thermal response of steelwork penetrating a fire-rated compartment wall

Abstract

Steelwork penetrating through fire-rated compartment walls can sometimes pose a challenge to ensuring the adequacy of compartment lines. This study investigates the thermal performance of steel beams penetrating fire-rated compartment walls, focusing on heat transfer mechanisms and their implications for insulation criteria. Using Finite Element Modelling, the research evaluates protected and unprotected steel beams in various wall types, including masonry, mass timber, and plasterboard-lined light steel stud wall. The penetration through solid walls, such as brick or mass timber, exhibits similar thermal behaviour, with the required fire protection length primarily dependent on the section factor of the steel rather than wall thickness. Notably, steel beams with a section factor above 150 m⁻¹ require consistent protection lengths across different solid wall materials. In contrast, plasterboard-lined light steel stud walls introduce greater complexity due to additional variables, such as cavity width and plasterboard configuration, influencing the temperature profile of the steel beam. The study highlights the inverse relationship between the section factor and the length of the steel exceeding insulation criteria, emphasizing the need for tailored fire protection strategies. These findings provide critical insights for improving fire safety in designs involving steel penetrations and underscore the necessity of case-specific analysis to ensure compliance with fire resistance requirements.