Structural protection · Section factor
What is a steel section factor and why does it matter?
A section factor expresses how much heated surface a steel member has relative to how much steel there is to absorb the heat — in Australian practice the exposed surface area divided by the mass of the member, expressed in square metres per tonne. European and ISO documents use a surface-area-to-volume form instead, so a figure taken from an overseas source is not directly comparable with the tables in an Australian assessment. A high section factor means a member heats quickly for its size and needs more protection; a low one means the opposite. It is one of the inputs that determines the protection thickness required, alongside the design requirement and the tested system. Who establishes it on a given project is a responsibility question rather than a technical one, and it is worth settling early.
What to do next
Send the tag, the schedule reference, the drawings you have and photographs of the actual condition. We will tell you what they show, what they cannot, and what else is needed before anyone gives a conclusion.
General information only. A conclusion about a specific condition requires the actual construction, the evidence behind it and the site condition to be reviewed.