Live Webinar
Quantitative analysis of gypsum calcination caused by a fire is of great use in fire investigations. The rate and the depth of calcination through the gypsum board are dictated by the heat and mass transfer through it.
The measurement of the depth of calcination is an integral part of fire investigations. The depth and extent of calcination of gypsum board can be measured using a depth of calcination caliper or another similar instrument. The relationship between the calcined and non-calcined areas on the gypsum wallboard can also display lines of demarcation. By plotting the depth of calcination measurements, investigators can see lines of demarcation and patterns not visible to the naked eye.
In recent years, the use of computer fire modeling in fire investigations has increased. Currently, more comprehensive and in-depth studies are necessary to understand the relationship between the history of fire spread and the depth of calcination. However, the ability to predict the depth of calcination in a compartment fire will improve the reliability and accuracy of fire investigation conclusions.
This presentation will compare the experimental results of gypsum calcination to the results predicted by a one-dimensional, in-house, unsteady computational model. The controlled laboratory-scale experiments are conducted with gypsum wallboard exposed to a uniform heat flux. During this exposure, the internal temperature profile is recorded using an array of 12 thermocouples, placed at different depths inside the gypsum board, and the depth of calcination is measured. This presentation quantifies of the heat flux and the duration of exposure effects the depth of calcination.
This presentation will also explore the nonlinearity in the propagation of dehydration front during gypsum calcination through the combined experimental and numerical study. This is done by comparing the internal temperature profile from the experiments to the temperature profile predicted by the model and comparing the percentage of dehydration predicted by the model to the depth of calcination measured in the experiments.