18. A new type of insulating board has been developed by that esteemed construction organisation Kaput Co. They warn that at extremely high heat fluxes it could be ignited, but they

don't think it's very likely and it would take hours, so there's no real risk! As an expert on the ignitability of materials, you are asked to perform a thick/thin calculation given the following data on the material: Density Thermal conductivity Specific heat capacity Thickness of board Initial/ambient laboratory temperature Ignition temperature 2300 kg m-3 0.85 W m¹¹ K-¹ 847 J kg-¹ K-¹ 8 mm 18 °C 415 °C It is considered that if 20 kW m² would be enough to ignite most materials (i.e. indicative of flashover fires). Perhaps something easy to ignite would only require 10kW m². Would this material ignite within ten minutes if exposed to 10kW m-²? Useful formulae: a = k/ pc 8=2. lat