(1)
Except as provided in Sentence (2), chimneys shall be braced in accordance with Subsection 4.3.2. to provide lateral stability under wind loads.
(2)
A chimney need not be laterally braced provided
(a)
no horizontal outside dimension is less than 400 mm, and
(b)
the chimney extends not more than 3.6 m above a roof or the masonry wall of which it forms a part. (See Note A-9.21.4.5.(2))