98
3220.057
Harmathy, T.Z. and J.A.C. Blachard
Special Report XLO.137
Paper
National Research Council, Canada, Division of Building Research
1961
August
1-9
Y
The variation of the average furnace temperature is shown. The uniformity of the furnace temperature was satisfactory. After 15 min. run the local deviation from the average temperature was less than 100°F.The temperatures obtained from various points of the test specimen are also plotted.
The temperature of the steel section rose rather uniformly. After 2 hr. 40 min. thermocouple No. 9 began recording moderately higher temperatures than the rest.
The small difference between the temperature of the steel section and the temperature of the unexposed side of the masonry work manifests the unimportant part that the air gap plays in the protection of the steel.
According to the alternate test procedure prescribed for protected steel columns by ASTM E119-58 the column shall be judged as failed if the average temperature at any one of the four levels exceeds 1000°F or the temperature at any one of the measured points exceeds 1200°F. The 1000°F limit was first exceeded at the level of thermocouples Nos. 7, 8 and 9 (level B in Figure 6) at 4 hr. 40 min. The 1200°F limit was not reached until the termination of the test which took place at 4 hr. 51 min.
Twenty-four hours after the completion of the fire test a few fine cracks became visible on the surface of the specimen. The condition of the specimen after the fire test is shown.
According to ASTM E119-58 the fire endurance test is regarded as successful for a 4 hr. period.