(1)
Except as permitted by Sentences (2) and (3), the flame-spread rating shall be not more than 75 for the interior wall finish of
(a)
(b)
a corridor used by the public in,
(i)
an assembly occupancy, or
(ii)
a care, care and treatment or detention occupancy,
(c)
a corridor serving classrooms, or
(d)
a corridor serving sleeping rooms in a care, care and treatment or detention occupancy.
(2)
The flame-spread rating for corridors specified in Sentence (1) is permitted to be waived, provided the flame-spread rating is not more than
(a)
25 on the upper half of the wall, and
(b)
150 on the lower half of the wall.
(3)
Where the floor area is sprinklered throughout, the flame-spread ratings for corridors specified in Sentences (1) and
(2) shall be not more than 150.
(4)
The flame-spread ratings specified in Sentences (1), (2) and (3) apply to occupancies in the corridor as well as to the corridor itself.
(5)
Except as provided in Sentence (6), the interior ceiling finish of corridors and occupancies referred to in Sentences (1) and (4) shall have a flame-spread rating not more than 25.
(6)
Where the floor area is sprinklered throughout, the flame-spread rating of the interior ceiling finish of corridors and occupancies referred to in Sentences (1) and (4) shall be not more than 150.