Standard Fire Test Methods

The test and acceptance criteria the NBCC refers to are contained in a standard fire test method, CAN/ULC-S101, Standard Method of Fire Endurance Tests of Building Construction and Materials, published by Underwriters Laboratories of Canada.

Alternative Fire Test Methods

The NBCC permits the authority having jurisdiction to accept results of fire tests performed according to other standards. Since test methods have changed little over the years, results based on earlier or more recent editions of the CAN/ULC-S101 standard are comparable.

The primary US fire-resistance standard, ASTM E119, is very similar to the CAN/ULC-S101 standard.

Both use the same time-temperature curve and the same performance criteria. Fire-resistance ratings developed in accordance with ASTM E119 are usually acceptable by Canadian officials. Whether an authority having jurisdiction accepts the results of tests based on these standards depends primarily on the official's familiarity with them.

Availability of Test Results
A multitude of fire-resistance tests have been conducted over the last 70 years by North American laboratories. Results are available through:

• Underwriters Laboratories of Canada
• Intertek Testing Services ETL SEMKO
• Underwriters Laboratories Incorporated
• Factory Mutual Research Corporation

In addition, manufacturers of construction products publish results of fire-resistance tests on assemblies incorporating their proprietary products (for example, Gypsum Association's Fire Resistance Design Manual).

Testing laboratories and manufacturers also publish information on proprietary listings of assemblies which describe all materials used and assembly methods. Figures 3 & 4 reproduce information published by ULC.

Figure 3: Listed wood joist floor assembly

End joint detail

Design No. M503 Unrestrained Assembly Rating: 2h

Combustible Construction

(Finish Rating - 75 minutes)

Finish Flooring: 19 x 89mm T & G flooring laid perpendicular to joists or 15.5mm select sheathing grade T & G phenolic bonded Douglas Fir plywood with face grain perpendicular to joists and joints staggered. Building Paper (optional): Commercial sheathing material, 0.25mm thick. Sub-flooring: 19 x 140mm T & G boards laid diagonally to joists or 12.5mm unsanded sheathing grade phenolic bonded Douglas Fir plywood with face grain perpendicular to joists and joints staggered. Bridging: 19 x 64mm Wood Joists: 38 x 235mm spaced 400mm O.C., firestopped. Furring Channel: Resilient, formed of 0.5mm electrogalvanized steel as shown, spaced 600mm O.C. perpendicular to joists. Channels overlapped at splice 38mm and fastened to each joist with 63mm common nails. Minimum clearance of channels to walls, 20mm. Additional pieces 1500mm long placed immediately adjacent to channels at end of joists of second layers; ends to extend 150mm beyond each side of end joint. Gypsum Wallboard: (Guide No. 40U18.23). 15.9mm thick, 1200mm wide. First layer of wallboard installed with long dimension perpendicular to joists and end joints of boards located at the joists. Nailed to joists with uncoated 63mm box nails spaced 180mm O.C. All nails located 15mm minimum distance from the edges and ends of the board. Second layer of wallboard secured to furring channels by 25mm long wallboard screws. Second layer installed with long dimension perpendicular to the furring channels and centre line of boards located under a joist and so placed that the edge joint of this layer is not in alignment with the end joint of the first layer. Secured to furring channels with wallboard screws 300mm O.C. with additional screws 75mm from side joints. End joints of wallboard fastened at additional furring channels as shown in end-joint detail. All screws located 25mm minimum distance from edges of boards.         ATLANTIC GYPSUM, a division of the Lundrigans-Comstock Limited         DOMTAR INC.         GEORGIA PACIFIC CORPORATION         WESTROC INDUSTRIES LIMITED Wallboard screws:Type S Phillips self-drilling and self-tapping 25mm long. Joint System (not shown): Paper tape embedded in cementitious compound over joints and exposed nail heads covered with compound, with edges of compound feathered out.

Reproduced by permission of Underwriters Laboratories of Canada.

Figure 4: Listed wood stud wall assembly

Design No. U301 Assembly Rating: 2h

Bearing Wall - Combustible Construction

(Finish Rating - 66 minutes)

Nailheads: Exposed or covered with joint finisher. Joints: Exposed or covered with tape and joint finisher. Nails: 51mmm, cement-coated flathead. Gypsum Wallboard: (Guide No. 40U18.23), 15.9mm thick applied in two layers. Base layer placed vertically with joints butted over studs and nailed to studs 150mm O.C. Face layer applied horizontally with joint finisher cement and nailed 300mm O.C. temporarily to base layer until cement sets. All joints in face layers staggered with joints in base layers and with joints on opposite sides.         Canadian Gypsum Company, Limited, A division of CGC Inc.         Domtar Inc.

Reproduced by permission of Underwriters Laboratories of Canada.

The NBCC contains fire and sound resistance tables describing various wall and floor assemblies of generic building materials and assigns specific fire resistance ratings to the assemblies.Over the last two decades a number of large research projects were conducted at the National Research Council of Canada (NRCC) on light-frame wall and floor assemblies looking at both fire resistance and sound transmission. As a result, the 2010 NBCC has hundreds of different wall and floor assemblies with assigned fire-resistance ratings and sound transmission ratings.These results are published in the NBCC Table A-9.10.3.1.A. Fire and Sound Resistance of Walls and NBCC Table A-9.10.3.1.B Fire and Sound Resistance of Floors, Ceilings and Roofs. Not all assemblies described were actually tested. The fire-resistance ratings for some assembles were extrapolated from fire tests done on similar wall assemblies.

The listings are useful because they offer off-the-shelf solutions to designers. They can, however, restrict innovation because designers use assemblies which have already been tested rather than pay to have new assemblies evaluated. Listed assemblies must be used with the same materials and installation methods as those tested.