To limit the probability that the rain load described in Sentence 4.1.6.4.(1), which is used for the design of structural elements supporting a roof area on which rain can accumulate, will not take into account the maximum expected accumulation of rainwater on the roof when drainage systems, such as rainwater leaders, are blocked by debris, which could lead to the excessive deformation of, or excessive stress in, structural elements, which could lead to damage to the building.