NFPA 262-2019 Standard Method of Test for Flame Travel and Smoke of Wires and Cables for Use in Air-Handling Spaces.
6.6.2 Preheating shall be continued until the temperature indicated by the foor thermocouple at 7.09 m ± 13 mm (23.25 ft ± 0.5 in.) reaches 66°C ± 3°C (150°F ± 5°F). 6.6.3 The fre test chamber shall be allowed to cool until the foor thermocouple at 3.96 m (13 ft) shows a temperature of 41°C ± 3°C (105°F ± 5°F). 6.6.4 Test Flame. 220.127.116.11 The steel plate, three 2.44 m (8 ft) long uncoated fber-reinforced cement boards, and the removable top shall be placed as in 6.6.1. 18.104.22.168 The fuel supply, methane gas, shall be adjusted to the required fow as described in Section 6.5, with the air-inlet shutter providing an opening of 76 mm ± 1.5 mm (3 in. ± 0.06 in.), for a test period of 10 minutes. 22.214.171.124 The temperatures indicated by the thermocouple in the fre test chamber air at 7.01 m (23 ft) shall be recorded at a maximum of 2-second intervals.
126.96.36.199 An arithmetic average of three readings over a 0.3 m (1 ft) length of the specimen shall be used as the specimen diameter. 7.2.3 The vernier caliper shall be permitted to be used for all sizes of cable specimens and shall be considered for small- diameter cables that are nonuniform in cross-section. 7.2.4 If the sample is round, the caliper shall be closed gently around the cable, carefully so as not to compress it, and the reading shall be taken. 188.8.131.52 The measurement shall be repeated a minimum of fve times over a length of 0.3 m (1 ft) of cable. 184.108.40.206 The arithmetic average of the fve readings shall be used as the cable specimen diameter. 7.2.5 Nonuniform Specimen. 220.127.116.11 If the specimen is nonuniform in cross-section, with the width-to-thickness ratio less than 2:1, three measurements shall be taken at wide points, and three measurements shall be taken at the narrow points of the sample. 18.104.22.168 The arithmetic average of the six readings shall be used as the specimen diameter. 7.2.6 If the width-to-thickness ratio is greater than 2:1, then the width of the specimen shall be used as the specimen diame‐ ter. 22.214.171.124 The width of the specimen shall be measured at six locations on a 0.3 m (1 ft) length of the cable. 126.96.36.199 The arithmetic average of the six readings shall be used as the specimen diameter.
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