UL 1709:2022 free download

UL 1709:2022 free download Rapid Rise Fire Tests of Protection Materials for Structural Steel
1 scope
1.1This Standard describes a full-scale test method for measuring the thermal resistance of protectivematerials, systems, or constructions to rapid-temperature-rise fires.
1.2 Part 1 of this Standard describes the furnace calibration and furnace control requirements.2Units of Measurement
2.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.
3 Referenced Publications
3.1 Any undated reference to a code or standard appearing in the requirements of this Standard shall beinterpreted as referring to the latest edition of that code or standard.
3.2The following publications are referenced in this Standard:UL 2431, Durability of Fire Resistive Coatings and MaterialsFULL-SCALE TEST METHOD
4Furnace Control
4.1The fire environment within the furnace is to develop a total heat flux of 65,000 +5000 Btu/h · f-(204±16 kW/m2) and an average temperature of 2000 ±100 °F (1093 156 °C)within 5 min from the start of thetest. The fire environment is to be controlled by reproducing the furnace temperatures recorded during thefurnace calibration method specified in the Furnace Calibration section of the relevant Part of thisStandard. This temperature is to be maintained throughout the remainder of the fire test as shown inFigure 4.1.
4.2 The furnace is to be controlled to maintain the area under the time-temperature curve to within 10 % of the corresponding area under the standard time-temperature curve shown in Figure 4.1 for fire tests of 60 min or less duration; to within 7.5 % for tests longer than 60 min but not longer than 120 min; and to within 5 % for tests exceeding 120 min in duration. The area under the time-temperature curve is to be obtained by averaging the results from the pyrometer or thermocouple readings.
4.3 A correction is to be applied for variation of the furnace exposure from the prescribed, where such variation will affect the test results, by multiplying the indicated time period by two-thirds of the value obtained by dividing the difference in area between the curve of average furnace temperature and the standard curve for the first three-fourths of the period by the area between the standard curve above a base line of 68 °F (20 °C) for the same part of the indicated period during the first part of the test. For fire exposure times longer than standard, the indicated rating period is to be increased by the amount of the correction and for fire exposure times less than standard, the indicated rating period is to be similarly decreased. The correction can be expressed by the following formula:
In which:
C is the correction in the same units as I
I is the indicated fire-resistance period