One result of the recent trend toward open office environments
is that smoke from office fires is not contained or isolated
as effectively as in less open designs. Open office designs
allows smoke to spread quickly and the incorporation of
many synthetic and other combustible material in office
fixtures (such as furniture, rugs, drapes, plastic wastebaskets,
and vinyl covered walls) often makes "smoky" fires.
In addition to being smoky, many synthetic materials can
emit toxic materials during a fire. For example, cyanide
can be emitted from urethane which is commonly used in upholstery
stuffing. Most burning materials can emit carbon monoxide.
Inhalation of these toxic materials can severely hamper
an office worker’s chances of getting out of a fire
in time. This makes it imperative for office workers to
recognize the signal to evacuate their work area and know
how to exit in an expedient manner
The vital necessity in layout planning is to provide a
safe and easily identifiable means of egress for all the
floor occupants by means of aisles to the exit stairs in
case of fire or other emergency. It is absolutely vital
that all aisles form naturally flowing paths and that they
be continuously maintained free of all impediments. Furniture
or furnishings including screens, coat racks, potted plants
which may be upset under emergency conditions are to be
kept out of the path of exit travel in the aisles.
Aisles are to conform to the following requirements:
Main aisles are to be provided on all floor areas to provide
access to at least 2 exits, and arranged to minimize any
possibility that both exit routes may be blocked by fire
or other emergency conditions.
Subsidiary aisles are to be provided to give access to main
aisles.
The travel distance from any point on a floor area to an
exit, measured along the path of travel, including subsidiary
and main aisles shall not exceed 40 m.
The travel distance from any point on a floor area to an
exit, measured along the path of travel, including subsidiary
and main aisles shall not exceed 45m, provided the floor
area is sprinklered.
Main aisles are to be a minimum clear width of 1100 mm.
Subsidiary aisles are to be of a minimum clear width of
900 mm.
The maximum permissible length of a dead end aisle is 7.5
m.
Every individual work area is to be located adjacent to
an aisle or subsidiary aisle.
Main aisles and subsidiary aisles are to be located to facilitate
access to fire alarm pull stations, emergency telephone,
firstaid and fire fighting equipment.
Main aisles and subsidiary aisles are to be continuously
maintained and kept free from all obstructions.
All aisles are to be equipped with an illumination level
of not less than 50 lx.
Floor layouts of main and subsidiary aisles are to be posted
on all floors together with the Fire Orders for the building.
Walking surfaces are to be kept in good repair and free
from tripping hazards.
Exit Marking
All exits doors, other than a main entrance to a room or
building, are required to be identified by illuminated exit
signs. Where such signs are not readily visible from main
and subsidiary aisles due to obstructions, or when there
is any possible doubt as to the means of egress, passageways
shall be provided with a suitable arrow or pointer indicating
the direction of egress.
Interior Finish Materials
The interior finish material has to conform to the Building
Code,1995.
Interior finish includes that for walls, partitions of
the fixed or movable types, ceilings, floors, and other
exposed interior surfaces of buildings. It includes interior
cladding of plaster, wood or tile; surfacing of fabric,
paint, plastic, veneer or wallpaper; doors, windows and
trim; lighting elements such as light diffusers and lenses
forming part of the finished surface of the ceiling, and
carpet material.
The characteristics of interior finish materials that are
relevant to the fire problem are their ability to spread
fire (flame spread rating), contribute fuel to a fire, and
the quantity of smoke they develop (smoke developed classification)
when burning. The generation of toxic gases as part of the
burning process is also recognized as a life hazard.
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Ceiling Finish
As heat and consequently flame rises, the fire behavior characteristics
of the ceiling finish, including any light diffusers or lenses
and baffles, are of critical importance. In a high rise building,
the flame spread rating must not exceed 25, and the smoke
developed classification must be not more than 50.
Light Diffusers and Lenses
Diffusers or lenses must have a flame spread rating and
smoke developed classification in conformance with CAN/ULC-S102.2-M88,
'Standard Method of Test for Surface Burning Characteristics
of Flooring, Floor Covering, and Miscellaneous Materials
and Assemblies'. The fixtures must also be designed so that
the lens will drop out before it ignites when exposed to
heat from a fire. The material must, therefore, also meet
the criteria set out in the standard CAN/ULC-S102.3-M82,
'Standard Method of Fire Test of Light Diffusers and Lenses'
as stipulated by the Building Code.
Screens and Partitions
Movable partitions or screens, including acoustical screens,
must not have a flame-spread rating greater than the requirement
for the interior finish of the area in which they are located.
Movable partitions and screens must have a flame spread
rating not exceeding 150 and a smoke developed classification
not exceeding 300 when tested in accordance with CAN/ULC-S102-M89,
'Standard Method of Test for Surface Burning Characteristics
of Building Materials and Assemblies'.
Floor Finish
Linoleum and vinyl asbestos tiles used as flooring materials
have an excellent fire record. They have been rarely involved
in office fires except under total burnout conditions.
In office areas in high buildings the flame spread rating
of the floor surface must not exceed 25 and the smoke developed
classification must not exceed 50.
Furnishings and Decorations
All furnishings and decorations, including curtains or drapes,
artificial plants and other decorative material are required
to conform to CAN/ULC-S109-M87, 'Flame Tests of Flame-Resistant
Fabrics and Films'.
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