Technical library
Structural protection
Protection to structural steel, and the asbestos question in older sprayed coatings.
Structural protection articles
Can damaged structural fire protection be repaired?
Often, if the existing system can be identified and its repair instructions or supporting evidence cover the damage. A patch is not automatically valid just because it uses the same-looking material.
Scott CunninghamCan old sprayed fire protection on structural steel contain asbestos?
Yes. Sprayed coatings applied to steel between roughly the 1930s and the 1970s were often asbestos-based, and fire protection of beams and columns was one of their main uses. Appearance alone cannot tell you. Because sprayed coatings are friable, the safest assumption on a building of that era is that the material is asbestos until an assessment says otherwise.
Scott CunninghamHow does structural steel fire protection work?
Steel loses strength as it heats. Protection systems slow that heating so the member holds its required performance for the required period. The system is selected against the member, the design requirement and the supporting evidence — not against a general idea of thickness.
Scott CunninghamHow is the required thickness of steel fire protection determined?
Required thickness comes from the system's test or assessment evidence read against the member and the design requirement. There is no universal table, and any figure published without its system and conditions is misleading.
Scott CunninghamSprayed protection, intumescent coating or board encasement: what is the difference?
Sprayed, intumescent and board systems solve the same problem differently, and differ in cost, appearance, application conditions, environmental tolerance, programme and the evidence behind them. The choice is a design decision, not a finish preference.
Scott CunninghamWhat 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.
Scott Cunningham
Still not sure what you are looking at?
Send the tag, the schedule reference and photographs of the actual condition. We will tell you what they show and what else is needed.