(1)
A firewall shall extend from the ground continuously through, or adjacent to, all storeys of a building or buildings so separated, except that a firewall located above a basement storage garage conforming to Article 3.2.1.2. is permitted to commence at the floor assembly immediately above the storage garage. (See also Sentence 3.1.10.1.(3))
(2)
A firewall is permitted to terminate on the underside of a reinforced concrete roof slab provided
(a)
the roof slab on both sides of the firewall has a fire-resistance rating not less than
(i)
1 h if the firewall is required to have a fire-resistance rating not less than 2 h, or
(ii)
2 h if the firewall is required to have a fire-resistance rating not less than 4 h, and
(b)
there are no concealed spaces within the roof slab in that portion immediately above the firewall.