N.Y.C. Admin. Code § 27-619: § 27-619 Use of non-stress grade wood.

The use of non-stress grade wood in structural elements shall be limited to the following conditions:

(a) Studs, joists, and rafters proportioned on the basis of the empirical provisions of section 27-622 of this article.

(b) The architect or engineer responsible for the design may assign an allowable stress value for the proposed material based on the provisions of reference standard RS 10-8 relating to "other species and grade". Under such condition, the required species and grade of wood, together with the assigned stress value, shall be conspicuously indicated on the plans.