To exempt foamed plastic insulation installed in ceiling spaces from the requirements of Sentence 188.8.131.52.(5), which would otherwise prohibit its use, if certain conditions are met.
This is to limit the probability that foamed plastic insulation will not be protected by a thermal barrier, which could lead to the insulation contributing to the growth or spread of fire, which could lead to the spread of fire to other parts of the building by means of the ceiling space, which could lead to harm to persons.
To expand the application of Article 184.108.40.206. [more specifically Sentence 220.127.116.11.(4)], which would otherwise apply only to buildings described in Sentence 18.104.22.168.(1) of Division A that are required to be of noncombustible construction.