To limit the probability that excessively high sound levels will be transmitted into a dwelling unit from an elevator shaft or a refuse chute, which could lead to persons being exposed to excessively high sound levels in the dwelling unit, which could lead to negative effects on the psychological well-being of persons.
To supersede the requirement of Sentence (1) and require a rating of not less than 55, in cases where dwelling units are adjacent to elevator shafts and refuse chutes, on the basis that elevators and chutes are expected to generate relatively high noise levels.