(1)
A door assembly having a fire-protection rating not less than 20 min is permitted to be used as a closure in
(a)
a fire separation not required to have a fire-resistance rating more than 1 h, located between
(i)
a public corridor and a suite,
(ii)
a corridor and adjacent sleeping rooms, or
(iii)
a corridor and adjacent classrooms, offices and libraries in Group A, Division 2 major occupancies, or
(b)
a fire separation not required to have a fire-resistance rating more than 45 min, located in a building not more than 3 storeys in building height.
(2)
The requirements for noncombustible sills and combustible floor coverings in NFPA 80, “Standard for Fire Doors and Other Opening Protectives,” do not apply to a door described in Sentence (1).
(3)
A door described in Sentence (1) shall have clearances of not more than 6 mm at the bottom and not more than 3 mm at the sides and top.
(4)
In elementary and secondary schools, a door assembly conforming to Articles 9.10.13.2. and 9.10.13.3. is permitted to be used as a closure in a fire separation having a fire-resistance rating of 30 min.