To limit the probability that the rain load used for the design of structural elements supporting roofs where scuppers are provided and on which rain can accumulate will not take into account the maximum expected accumulation of rainwater on a catchment area of roof, including an allowance for rain accumulation above the scupper level, which could lead to structural failure, which could lead to harm to persons.
To limit the probability that the one-day rainfall value used will not be compatible with the geographic characteristics by directing Code users to Sentence 1.1.3.1.(1) [Appendix A], which could otherwise lead to structural failure, which could lead to harm to persons.