A textile floor covering consisting of 48 specimens, each measuring not less than 23 cm × 23 cm (9" × 9"), must be tested in accordance with the normal sequential sampling plan set out in the Canadian General Standards Board (CGSB) 4-GP-155 (1974), Standard for Flammability of Soft Floor Coverings - Sampling Plans, and the flame resistance test method set out in CGSB 4-GP-2 (1971), Method 27.6 of the Canadian Standard Textile Test Methods, Method of Test for Flame Resistance - Methenamine Tablet Test. A textile floor covering that has been treated with a fire retardant must also be subject to removal of the fire retardant finish prior to being tested for flame resistance, using the method set out in CGSB 4-GP-2 (1971), Method 30.2 of the Canadian Standard Textile Test Methods, Procedure for the Removal of Flame Retardant Treatments on Textile Floor Coverings.
In brief, 48 specimens are cut from the textile floor covering and, where applicable, the fire retardant finish is removed. The specimens are then conditioned, dried and brought to room temperature. A randomly selected specimen is placed horizontally in a test chamber in a draft free environment and a steel frame is placed on top of the specimen. A methenamine tablet is placed in the centre of the specimen and lit. After all combustion has ceased, the shortest distance between the charred area of the specimen and the inside edge of the frame is measured.
A specimen passes if the shortest distance between the charred area of the specimen and the inside edge of the frame is greater than 25.4 mm (1"), and fails if the distance is less than or equal to 25.4 mm.