N.Y.C. Admin. Code § 27-269: § 27-269 Construction classes.

Table 3-3 lists construction classes that shall be established for classifying buildings and spaces by construction in accordance with the provisions of articles fifteen, sixteen and seventeen of this subchapter.

TABLE 3.3 Construction Classes

Construction Group

Class

I – Noncombustible

I – A – (4-hr. protected)

I – B – (3-hr. protected)

I – C – (2-hr. protected)

I – D – (1-hr. protected)

I – E – (unprotected)

II – Combustible

II – A – (heavy timber)

II – B – (protected wood joist)

II – C – (unprotected wood joist)

II – D – (protected wood frame)

II – E – (unprotected wood frame)