UL 10C-2021 pdf free download.Positive Pressure Fire Tests of Door Assemblies.
4.2 Uniformity of temperature distribution
4.2.1 At any time after the first 10 minutes of fire exposure, the temperature nse indicated by any of the thermocouples used to determine the furnace temperature shall not differ from each other by more than 270° F (150° C). With test constructions where either the sample or any associated construction incorporates combustible materials that produce flaming within the furnace or where excess air drawn into the furnace is identified as causing localized heating or cooling of one or more of the furnace thermocouple hot junctions. the deviation of temperature rise from each other recorded by the thermocouples so affected shall not exceed 450°F (250°C).
5 Furnace Temperatures
5.1 The temperatures of the test exposure shall be the average temperature obtained by a minimum of three thermocouples and no fewer than one thermocouple per 15 square feet of test assembly exposed to the furnace symmetrically disposed and distributed to show the temperature near all parts of the test assembly, Figure 5.1. The thermocouples shall be protected by: (1) sealed 1/2 in (12.7 mm) wrought-steel or wrought-iron pipe of standard weight or (2) Inconel 600 series schedule 40 pipe (0.8 inch OD I 0.6 inch ID, 20 mm OD /15 mm ID).
5.2 The junction of the thermocouples shall be initially located 6 in (152 mm) from the exposed face of
the test assembly or from the construction in which the assembly is installed. During the fire exposure, if
the movement of the test sample causes the sample’s distance to the thermocouple junction to vary, the
location of the junction shall be reset to 6 in (152 mm) at intervals not exceeding 10 minutes during the first
30 minutes of the test. Thereafter, the intervals are to be increased to not more than 30 minutes.
5.3 The temperatures shall be read at intervals not exceeding 1 minute.
5.4 The accuracy of the furnace control shall be such that the area under the time-temperature curve, obtained by averaging the results from the thermocouple readings, is within 10 percent of the corresponding area under the standard time-temperature curve for fire tests of 1 hour or less duration, within 7.5 percent for those over 1 hour and not more than 2 hours, and within 5 percent for tests exceeding 2 hours in duration.
5.5 For a summary of the accuracies for the various rating periods, see Appendix .UL 10C pdf download.