NFPA 701-2019 Standard Methods of Fire Tests for Flame Propagation of Textiles and Films.
188.8.131.52 When the pin bar and hanger are placed, the side of the specimen facing the back wall of the test chamber shall be 25 mm ± 2 mm (1.0 in. ± 0 .0 8 in.) from the wall surface.
8.2 Burner Placement and Preparation.
8.2.1 The burner shall be placed so that it is 25 mm ± 2 mm (1.0 in. ± 0 .08 in.) from the face of the specimen and with the center axis of the burner horizontal and perpendicular to the bottom of the center seam in the specimen.
8.2.2 Position adjustments shall be permitted to be made by moving the support base and by adjusting the height and angle of the burner.
8.2.3 The exhaust fan shall be turned on.
8.3 Conducting the Test.
8.3.1 The test shall be initiated within 2 minutes of removing the specimen from the forced-draft oven.
8.3.2 The gas shall be turned on fully at the burner control valve and allowed to flow for 20 seconds ± 1 second before it is ignited.
8.3.3 The specimen shall be exposed to the igniting flame foe
45 seconds ± 1 second.
8.3.4 After the 45-second exposure, the burner shall be turned on its mount so that its center axis is parallel to the plane of the specimen, and then the gas flow shall be turned off using the control valve on the burner.
8.3.5 The gas flow rate shall be controlled by the valve at the flow gauge.
8.3.6 Binder dips measuring 18 mm ± 1 mm 3 .75 in.
± 0 .04 in.) shall be attached to the specimen at each bottom corner.
184.108.40.206 Each binder clip shall have a weight of 3.0 g ± 0 .2 g (0 .1 oz ± 7 x 10 4 oz).
220.127.116.11 The dips shall be positioned such that the ‘biting edg& of each dip is 5 mm ± 1 mm (0 .20 in. ± 0 .04 in.) above the lower edge of the specimen.
18.104.22.168 The clips shall be placed 5 mm ± 1 mm (0 .20 In.
± 0 .0 4 in.) in from the left and right side edges of the specimen. respectively.
NFPA 701 pdf download.