3.4.4.2.(2)ATTRIBUTION:
Functional Statement:
F12
To facilitate emergency response.
F10
To facilitate the timely movement of persons to a safe place in an emergency.
F05
To retard the effects of fire on emergency egress facilities.
F06
To retard the effects of fire on facilities for notification, suppression and emergency response.
Objective:
OS1.5
APPLICATION:
Exits from floor areas above or below the first storey that lead through lobbies, where:
- the lobby floor is not more than 4.5 m above grade,
- the path of travel through the lobby to the outdoors is not more than 15 m,
- the adjacent rooms or premises having direct access to the lobby do not contain a residential occupancy or an industrial occupancy,
- the lobby is not located within an interconnected floor space other than as described in Sentence 3.2.8.2.(6),
- the lobby conforms to the requirements for exits, except that:
- rooms other than service rooms and storage rooms are permitted to open onto the lobby,
- the fire separation between the lobby and a room used for the sole purpose of control and supervision of the building need not have a fire-resistance rating,
- the fire separation between the lobby and adjacent occupancies that are permitted to open onto the lobby need not have a fire-resistance rating provided the lobby and adjacent occupancies are sprinklered, and
- passenger elevators are permitted to open onto the lobby provided the elevator doors are designed to remain closed except while loading and unloading passengers, and
- a fire separation, constructed in accordance with Sentence 3.4.4.1.(1), is maintained between the lobby and any exit permitted by this Sentence to lead through the lobby.
This applies to exits serving floor areas that are intended for occupancies, including mezzanines as stated in Sentence
3.4.2.2.(1),
in buildings described in Sentence
1.3.3.2.(1) of Division A.
This also applies to tents and air-supported structures, as stated in Sentences 3.1.6.1.(1) and 9.10.1.2.(1).
INTENT:
To supersede the requirements of Sentence
3.4.4.1.(1) for
a rated fire separation and of Sentence
3.4.4.2.(1) prohibiting exits
to lead through lobbies, if certain measures are taken.
This
is to limit the probability that:
- excessive height above grade of the lobby will delay fire emergency response operations, which could lead to delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons, including emergency responders,
- excessive travel distances through the lobby will lead to delays in evacuating, which could lead to harm to persons, and
- smoke from a fire in a room, premise or interconnected floor
space, or a fire in an adjacent occupancy, will spread into the lobby, which
could lead to untenable conditions in the exit, which could lead to:
- delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons,
- harm to persons, and
- delays or ineffectiveness in fire emergency response operations, which could lead to delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons, including emergency responders.