To supersede the requirements of Sentence 3.2.5.9.(1), which would otherwise require that standpipe and hose stations conform to certain design and installation standards [which would require supply from risers], and permit small hose stations to be supplied from interior sprinkler piping, if certain conditions are met [the building is sprinklered in conformance with Article 3.2.5.12.].
This is to limit the probability that fire suppression operations using small hose stations will be ineffective in controlling or suppressing a fire, which could lead to the spread of fire, which could lead to harm to persons.