(1)
Exit stair flights shall consist solely of
(a)
straight flights, or
(b)
curved flights complying with Sentence (2).
(2)
A curved flight used as an exit shall have
(a)
a handrail on each side,
(b)
a minimum run of 240 mm,
(c)
treads with a run that conforms to Article 3.4.6.8. when measured at a point 300 mm from the centre line of the inside handrail at the narrow end of the tread, and
(d)
an inside radius that is not less than twice the stair width.
(3)
Tapered treads shall have a consistent angle and uniform run and rise dimensions in accordance with the construction tolerances described in Article 3.4.6.8. when measured at a point 300 mm from the centre line of the handrail at the narrow end of the tread.
(4)
All tapered treads within a flight shall turn in the same direction.