Fire Resistance of Steel C-Joist Floor Assemblies


This paper discusses the factors that affect the fire resistance performance of lightweight steel-framed (LSF) unrestrained floor assemblies protected with Type X gypsum board ceiling finishes. Sixteen fire resistance experiments were conducted on full-scale load-bearing steel C-joist floor assemblies using the ULC standard fire exposure time–temperature curve that is similar to ASTM E119 standard. Parameters investigated in this study include the effects of insulation installation, insulation type, joist spacing, resilient channel installation, resilient channel spacing, type of sub-floor layer and number of sub-floor layers versus number of gypsum board layers. The impact of these parameters on the fire resistance of steel C-joist frame floor assemblies is discussed. The fire resistance of LSF floors appears to be essentially governed by the number of gypsum board layers, spacing of the joists or resilient channels where the gypsum boards are attached, sub-floor type and insulation type. Other parameters are of secondary importance.

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The National Research Council of Canada wishes to acknowledge the technical and financial contributions of the partners in this Joint Research Project. The partners include Boise Cascade, Canada Mortgage and Housing Corporation, Canadian Home Builders Association, Canadian Portland Cement Association, Canadian Sheet Steel Building Institute, Canadian Steel Construction Council, Canadian Wood Council, Cellulose Insulation Manufacturers Association of Canada, Forintek Canada Corp., US Gypsum Association, Gypsum Manufacturers of Canada, Louisiana-Pacific Corporation, Nascor Inc., Ontario Home Warranty Program, Ontario Ministry of Municipal Affairs and Housing, Truss Plate Institute, Truss Plate Institute of Canada, US Cellulose Manufacturers Association, Johns Manville International, Owens-Corning Canada, Willamette Industries, Roxul Inc., and Trus Joist MacMillan.

The author wishes to acknowledge the contributions from the Fire Research Program staff: J. C. Latour, P. Leroux, R. C. Monette, Y. P. Séguin, J. P. Henrie Joe Hum and Richard Rombough in constructing assemblies and conducting experiments.

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Correspondence to Mohamed A. Sultan.

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Sultan, M.A. Fire Resistance of Steel C-Joist Floor Assemblies. Fire Technol 46, 375–405 (2010).

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  • fire resistance
  • steel C-joist
  • insulation
  • resilient channel
  • concrete
  • rock fibre
  • glass fibre
  • gypsum board plywood