To exempt thermosetting foamed plastic insulation used in factory-assembled doors from the requirements of Sentence 9.10.17.10.(1), which would otherwise require certain protective coverings over the foamed plastic, if certain conditions are met.
This is to limit the probability that the foamed plastic insulation will be exposed to a fire, which could lead to its ignition and contribution to the early growth and spread of fire, which could lead to delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons.