Light gauge steel sections (also known as cold-formed steel sections) are formed by cold rolling thin steel sheet into shape. Thin steel sheet is typically 0.4 to 3.0 mm thick and pre-galvanised, such as with a zinc coating, for corrosion prevention.

Light gauge steel sections can be produced in a large variety of sections and profiled sheeting. In building construction, traditionally, the commonly used sections are “C” or “Z” shapes used as roof purlins and side rails to support the cladding in industrial buildings. Nowadays, light gauge sections have been widely used as steel frames, trusses, wall partitions, lintels, floor joists and storage racking etc.

In general, light gauge sections have the advantages of lightness and high strength-to-weight ratio at ambient temperature. The strain-hardening caused by the cold-working process increases the yield strength and ultimate strength of the materials. However, these characteristics make them more vulnerable to a fire attack compared to hot rolled sections. Light gauge sections possess little fire resistance because they would heat up quickly if directly exposed to fire due to their high section factors. The increase of mechanical strength, due to strain-hardening, will also be removed quickly during heating.

However, at present, the performance of light gauge steel in fire is only briefly described in Eurocodes and Bristish Standards. This section presents the basic design information of light gauge steel, followed by some background research studies.