New environmentally friendly firefighting foam formulations are being developed to replace aqueous film forming foam. In the formulation development stage, there is a need to have a cost-effective bench-scale test that can be used to evaluate performance with a minimal amount of foam solution. The objective of this research is to develop a bench-scale test that can evaluate the fire suppression performance of a foam formulation as well as generate data that quantifies the foam behavior characteristics. The foam characteristic data could be used to identify how to improve the foam and predict performance at other scales using models.
The bench-scale testing will be developed in the American Society for Testing and Materials E1354 cone calorimeter which is one of the most widely used bench-scale tests in fire science. The apparatus measures the heat release rate of burning materials when exposed to different heat levels, and it will be modified in this effort so that liquid pool fire suppression tests can be conducted in the test chamber. With this modification, the heat release rate of the pool fire with time will be measured and used to quantify fraction of fire controlled, control times, and extinguishment time. In addition, it is expected that by conducting these tests at different application rates the minimum application rate for control and minimum time for control can be quantified. These parameters are hypothesized by the proposer to be related to the foam loss and foam suppression characteristics. Through testing with different types of foam, the research will explore whether these parameters can be related to foam performance. A theoretical model based on a foam mass balance on the fuel surface will use these parameters as input in predicting the control time of the foam at a given application rate.
The experimental approach of this project is unique in that it uses oxygen consumption calorimetry to directly measure the heat release rate during the suppression process, allowing control time to be quantified based on a reduction in heat release rate. This eliminates the current qualitative measure of control time. The study will also provide a better understanding of the foam performance characteristics through analysis of data from tests at different application rates. These data will be used as model input data to predict fire suppression control time. In addition, foam performance characteristics will also provide formulation chemists with insight on how to improve their formulation. The bench-scale test developed in this effort will provide a rapid, cost-effective method to assess foam performance using limited solution.