Mathematical modeling of timeto ignition in the early fire hazard test

We present a one-dimensional numerical model and an analytical model for time to ignition in the Early Fire Hazard (EFH) test. To validate the numerical model, we show that the model can predict time-to-ignition results from EFH tests for plywood. These simulations are performed by using data taken from cone-calorimeter tests at steady imposed heat fluxes and applied to ignition data in the EFH for time-varying imposed heat fluxes, without prior detailed knowledge of the material properties. In addition, we propose modifications to the standard EFH test and develop an analytical theory, which would allow fundamental material fire properties to be determined. The analytical theory agrees well with the numerical results. The theory also explains the expected relationship between the results from the cone-calorimeter test and the EFH test.