Surface Temperature Measurement In A Fire Environment Using An Infrared Pyrometer

Abstract

If a surface temperature measurement were added to a heat release rate test apparatus like the standard ICAL, the net heat flux could be determined. Then the heat of gasification could be calculated for use in the CFD fire models. This paper describes the measurements of the surface temperature history of specimens in the ICAL using an infrared pyrometer operating in the 8 to 10 micron wavelength band. These temperatures were verified by simultaneous measurements with a bare 0.127 mm diameter type K thermocouple pulled tight against the surface of the specimen. As the burning surface receded during the test, the tension, and therefore the surface contact of the thermocouple, was maintained by weights attached to the thermocouple lead wires which passed through two small holes to the back of the specimen. Because of the strong vibrational bands common to organic polymers, there was very good agreement with the thermocouple for these materials when the spectral emissivity setting of the pyrometer was equal to 1.0. There was essentially no effect of the flames or smoke from the specimens in the ICAL on the temperatures indicated by the pyrometer.