N.Y.C. Admin. Code § 27-281: § 27-281 Construction class II-A.

Includes heavy timber construction in which fire-resistance is attained by limiting the minimum sizes of wood structural members and the minimum thickness and composition of wood floors and roofs; by avoiding concealed spaces under floors and roofs or by providing fire-stopping protection for these spaces; and by using fastenings, construction details, and adhesives for structural members as required by article seven of subchapter ten of this chapter. The minimum dimensions for framing members shall be prescribed in section 27-623 of article seven of subchapter ten of this chapter, except that members which are protected to provide a fire-resistance rating of at least one hour need not comply with this requirement.