This article explores how different types of cellular plastic insulation materials burn. The researchers used a cone calorimeter to measure the combustibility of these materials. They found that while the total heat released during burning was consistent for each type of insulation, the way they burned varied due to their composition. For most types of cellular plastic insulation, you can estimate how flammable they are by looking at their material composition and thermal behavior. However, for rigid urethane foam, understanding combustibility requires identifying specific factors like the nurate index and foaming agent used.