N.Y.C. Admin. Code § 27-877: § 27-877 Chimneys for industrial or municipal incinerator plants.

Chimneys for central incinerator plants shall be constructed in accordance with the requirements for:

(a) Medium temperature chimneys if the incinerator is provided with a heat recovery unit or other means to assure a flue gas temperature not in excess of one thousand degrees Fahrenheit at the base of the stack.

(b) High temperature chimneys if the incinerator has no heat recovery unit or other means to assure a flue gas temperature less than one thousand degrees Fahrenheit.