To limit the probability of the premature failure of chimney saddles under expected structural or environmental loads, which could lead to precipitation or meltwater ingress into or through roofs or chimneys, which could lead to damage to masonry or to chimney liners from freeze-thaw stresses, which could lead to the escape of heat or flames, which could lead to the ignition of combustible building components, which could lead to damage to the building [see analysis for Sentence 9.21.4.6.(1)].