N.Y.C. Admin. Code § 27-840: § 27-840 Charging chutes and exhaust flues.

All incinerators shall be constructed with a flue within a chimney to exhaust the products of combustion and a refuse charging chute which shall be separate from the flue. Refuse charging chutes shall not discharge directly into incinerators, except in buildings classified in residential occupancy group J and in accordance with the requirements of this subchapter and subchapter fifteen of this chapter. Flues for existing incinerators and existing refuse chutes may be used as refuse charging chutes provided they are in good condition and comply with the requirements of subchapter fifteen of this chapter.