The analysis of research results concerning heat release rates of ship materials with regard to dynamic parameters of the research station
The analysis of research results concerning heat release rates of ship materials with regard to dynamic parameters of the research station Based on the results of author's research it was stated that significant differences between heat release rates measured according to ISO 5660-1 and FTP Code Part 5 (Res. A. 653 (16)) are not caused by measurement uncertainties. A basic factor determining the lack of correlation is treating the heat release rate in the category of static measurements in the normalized measurement methods. Taking into account dynamic parameters of the test station allowed the coincidence rate (reproducibility and correlation) of the results of heat release rates measured using different methods to be improved, without changing test stations and procedures. Author's research performed on 42 materials has revealed that the relative dynamic errors of the heat release rate measurements are significant (2%÷120%). The average value of these changes for the tested group of materials was equal to 39%.
An evaluation of heat release criteria in reaction-to-fire tests
A theoretical approach is developed for evaluating quantitatively the heat evolved during a reaction-to-fire test. This involves determining the transfer function from two head balance equations, one concerning the walls and the other the air in the test box. A comparison between this theoretical approach and the empirical ‘area under the curve’ method has been made for 34 tests on electrical cables. It is shown that the empirical method is unacceptable.
Instantaneous Temperature Measurement
Measurement of temperature using a thermocouple or any other device requires a certain length of time. This time interval is of the order of magnitude of the thermal time constant of the measuring device. Here we describe an electronic circuit which makes the temperature measurement ``instantaneous.'' This is accomplished by combining the temperature at any instant with the rate of change of temperature. Thus the only limiting factor becomes the electronic time constant of the circuits involved. We have used our device in absolute measurement of optical power and have found that the typical time necessary for a temperature measurement can easily be 10–3 × the thermal time constant of the measuring device.