(a)
the difference in elevation is more than 600 mm between the walking surface and the adjacent surface, or
(b)
the adjacent surface within 1.2 m of the walking surface has a slope of more than 1 in 2.
(See Note A-9.8.8.1.)
(2)
Except as required by Sentence (4), the height of guards for exit stairs and exit ramps, as well as their landings, shall be not less than 1 070 mm.
(a)
a line drawn through the outside edges of the stair nosings, or
(b)
the surface of the ramp or landing.
(4)
The height of guards for exterior stairs and landings more than 10 m above adjacent ground level shall be not less than 1 500 mm measured vertically to the top of the guard from the surface of the landing or a line drawn through the outside edges of the stair nosings.
(5)
Except as provided in Sentence (5.1), openings through any guard that is required by Sentence (1) shall be of a size that will prevent the passage of a sphere having a diameter more than 100 mm unless it can be shown that the location and size of openings that exceed this limit do not represent a hazard.
(5.1)
Openings through any guard that is required by Sentence (1) and that is installed in a building of industrial occupancy shall be of a size that will prevent the passage of a sphere having a diameter more than 200 mm unless it can be shown that the location and size of openings that exceed this limit do not represent a hazard.
(6)
In a stairway, a window for which the distance measured vertically between the bottom of the window and a line drawn through the outside edges of the stair nosings is less than 900 mm, or a window that extends to less than 1 070 mm above the landing, shall
(a)
be protected by a guard that is
(i)
located approximately 900 mm above a line drawn through the outside edges of the stair nosings, or
(ii)
not less than 1 070 mm high measured to the top of the guard from the surface of the landing, or