N.Y.C. Admin. Code § 27-855: § 27-855 Factory-built chimneys and gas vents.

(a) Factory-built chimneys. Factory-built chimneys and chimney units shall be listed and accepted in accordance with the applicable reference standard and shall be installed in accordance with the temperature conditions and height limitations of the listing and acceptance, the manufacturer's instructions or this article, whichever is the most restrictive. Flue gas temperatures in the chimney shall not exceed the limits and durations employed during listing tests and as required by this code.

(b) Gas vents. Type B and Type BW gas vents shall be listed and accepted in accordance with the conditions of the acceptance and applicable provisions of this code.