Modeling and Simulation
GEOMET develops modeling and simulation tools for use by our scientists and other researchers, as well as professionals working in the field. Such tools have been developed for use on personal computers (PCs) as well as personal digital assistants (PDAs). We currently are developing a PDA tool, called the Heat Stress Calculator, to assist first responders and other wearers of personal protective equipment (PPE) in determining safe stay times from the standpoint of avoiding excessive heat stress. The Heat Stress Calculator has been developed as a stand-alone application that runs on a PDA using the Pocket PC operating system.
Two keys to our approach are accurate prediction of safe stay times for specific situations and ease of use by first responders. The application uses robust yet straightforward algorithms for prediction of cumulative heat storage for specific situations and provides a user interface with input menus and context-sensitive help for choosing appropriate input values.
The input screens for the application concern characteristics of the wearer of PPE, the type of activity undertaken, the PPE itself, and the surrounding environment. The outputs provided include time to work exhaustion, time to dehydration risk, and time to risk of heat injury. Thermal manikin testing was conducted to determine important characteristics (insulation and permeability) of PPE ensembles commonly used by firefighters and first responders dealing with hazardous materials or chemical/biological agents. Testing with firefighters and U.S. Marines wearing various ensembles was performed in an environmental chamber to provide a basis for assessing the accuracy of heat-storage predictions from the model.