To limit the probability that the interconnection or connection of exhaust ducts or shafts serving various areas of buildings will lead to the transfer of exhaust air containing grease or moisture to other parts of buildings, which could lead to the contamination of other spaces, which could lead to negative effects on the air quality of indoor spaces, which could lead to harm to persons.
To exempt certain exhaust systems from the application of Sentences 6.2.3.8.(10) and 6.2.3.8.(11), where safeguards are provided to avoid cross-contamination between the contents of various ducts.