9.8.4.4.(2)ATTRIBUTION:
Functional Statement:
F30
To minimize the risk of injury to persons as a result of tripping, slipping, falling, contact, drowning or collision.
F10
To facilitate the timely movement of persons to a safe place in an emergency.
Objective:
OS3.1, OS3.7
APPLICATION:
Angled treads in curved interior and exterior stairs,
for buildings to which Part 9 applies [see Sentence
1.3.3.3.(1) of Division A for application of Part 9].
This also applies to stairs within dwelling units in buildings to which Part 3 applies [see Sentence
1.3.3.2.(1) of Division A for application of Part 3], as
stated in Sentence
3.3.4.7.(1).
INTENT:
To limit the probability that an insufficient run in a curved
stair will not provide adequate support for users' feet, which could lead
to:
- persons falling during normal use -- when traffic flow is likely to be lower than for exit stairs during an emergency and users are likely to have the option of using the wider portion of the treads, or
- persons falling in an emergency -- when traffic flow is expected to be limited because of the presence of exit stairs as an alternate or the limited occupancy in a dwelling unit, and users are likely to have the option of using the wider portion of the treads -- which could lead to delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons.
This is to limit the probability of harm to
persons.