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 the excessive deformation of, or excessive stress in, structural elements, which could lead to damage to the building.
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 the excessive deformation of, or excessive stress in, structural elements, which could lead to damage to the building.