In C8 or M1 Districts, the Board of Standards and Appeals may permit schools which have no residential accommodations except accessory accommodations for a caretaker, as listed under Use Group III(B), provided that the following findings are made:

1. that within the neighborhood to be served by the proposed school there is no practical possibility of obtaining a site of adequate size located in a district wherein it is permitted as of right, because appropriate sites in such districts are occupied by substantial improvements;
2. that such school is located not more than 400 feet from the boundary of a district wherein such school is permitted as-of-right;
3. that an adequate separation from noise, traffic and other adverse effects of the surrounding non-Residential Districts is achieved through the use of sound-attenuating exterior wall and window construction or by the provision of adequate open areas along lot lines of the zoning lot; and
4. that the movement of traffic through the street on which the school is located can be controlled so as to protect children going to and from the school. The Board shall refer the application to the Department of Traffic for its report with respect to vehicular hazards to the safety of children within the block and in the immediate vicinity of the proposed site.

The Board may prescribe additional appropriate conditions and safeguards to minimize adverse effects on the character of the surrounding area.