Fire Resistance Testing of Modular Building Panels

The Challenge

Fire safety is a crucial issue for buildings, especially with the rise of modular construction which demands materials that combine lightness with mechanical performance and stability. These prefabricated systems use thin-walled panels, only 5 cm for walls and 7 cm for slabs, that must still meet fire resistance, insulation, and airtightness standards. Understanding how steel fiber-reinforced concrete panels perform under fire conditions is essential for building code compliance.

The Solution

This experimental study investigated 3D modular cells assembled from thermally and acoustically pre-insulated SFRC panels. The concrete contained 80 kg/m³ of steel fibers and 0.3 kg/m³ of polypropylene fibers. The GrindoSonic MK7 enabled measurement of residual elastic modulus after fire exposure, providing non-destructive evaluation of thermal damage extent and mechanical property degradation in the panels.

Results

Full-scale fire tests confirmed that the thin SFRC structures meet fire resistance, insulation, and airtightness standards. Adding polypropylene fibers effectively prevents concrete from splintering and achieves the necessary 30-minute fire resistance. The high volume of steel fibers provides ductility, maintaining structural integrity despite spalling depths of 35–50 mm in some areas. This research demonstrates that the modular system satisfies fire safety requirements for structural stability in single-story construction.

Key takeaway: SFRC panels with 5 cm walls and 7 cm slabs achieved 30-minute fire resistance ratings, with 0.3 kg/m3 of polypropylene fibers preventing explosive spalling despite localized depths of 35-50 mm.