Thermographic Phosphor Based Heat Flux Sensors

As fire protection engineering moves towards the implementation of performance- based fire codes, the use of validated fire models is becoming a necessity. Part of the validation process involves demonstrating model capabilities for predicting key fire environment parameters. One of the key parameters for estimating time to ignition and fire growth is the heat transfer rate to compartment surfaces and items in the compartment. The heat transfer rate or heat flux is also recognized as an important variable in the occurrence of flashover. Prototype, thermographic phosphor (TP) based heat-flux sensors will be developed to measure and distinguish between radiative and convective heat fluxes in fire environments. TP sensors also provide surface temperature information. In Phase 1, the sensors will use optical interrogation and readout from the unheated surface. Initial evaluation of the sensors for mixed mode heating will use a heated, free jet for convective heat transfer and a radiant source that provides an infrared spectral distribution that is representative of a fire, peak temperature approximately 1300K.