N.Y.C. Admin. Code § 28-103.17: § 28-103.17 Certain outside work, employment and financial interests of department employees prohibited.

It shall be unlawful for any officer or employee of the department to be engaged in conducting or carrying on business as an architect, engineer, carpenter, plumber, iron worker, mason or builder, electrician, or any other profession or business concerned with the construction, alteration, sale, rental, development, or equipment of buildings. It shall also be unlawful for such employees to be engaged in the manufacture or sale of automatic sprinklers, fire extinguishing apparatus, fire protection devices, fire prevention devices, devices relating to the means or adequacy of exit from buildings, or articles entering into the construction or alteration of buildings, or to act as agent for any person engaged in the manufacture or sale of such articles, or own stock in any corporation engaged in the manufacture or sale of such articles.