deisgn of fire escapes
TRANSCRIPT
SHARDA uNIVERSITY
Submitted By:-Ishan GargRajat AgrawalPikakshi Bharadwaj
SERVICES
Design of fire escapes
Fire escape:
• a special kind of emergency exit.
• provides a method of escape
• often found on multiple-
story residential buildings
• they have fallen out of common use
General Exit Requirements
An exit may be a doorway; corridor; passageway(s) to an
internal staircase, or external staircase, or to a
VERANDAH or terrace(s), which have access to the
street, or to the roof of a building or a refuge area. A exit
may also include a horizontal exit leading to an adjoining
building at the same level.
Lifts and escalators shall not be considered as exits.
Every exit, exit access or exit discharge shall be
continuously maintained free of all obstructions or
impediments to full use in the case of fire or other
emergency.
Every building meant for human occupancy shall be provided with exits
sufficient to permit safe escape of occupants, in case of fire or other
emergency.
In every building or structure, exits shall comply with the minimum
requirements of this part, excep those not accessible for general public use.
No building shall be so altered as to reduce the number, width or protection of
exits to less than that required.
Exits shall be clearly visible and the route to reach the exits shall be clearly
marked and signs posted to guide the occupants of the floor concerned. Signs
shall be illuminated and wired to an independent electrical circuit on an
alternative source of supply. The sizes and colours of the exit signs shall be in
accordance with good practice . The colour of the exit signs shall be green.
The floors of areas covered for the means of exit shall be illuminated to
values not less than 1 ft candle (10 lux) at floor level. In auditoriums, theatres,
concert halls and such other places of assembly, the illumination of floor
exit/access may be reduced during period of performances to values not less
than 1/5 ft candle (2 lux).
Fire doors with 2 h fire resistance shall be provided at
appropriate places along the escape route and
particularly at the entrance to lift lobby and stair well
where a ‘funnel or flue effect’ may be created, inducing
an upward spread of fire to prevent spread of fire and
smoke.
All exits shall provide continuous means of egress to the
exterior of a building or to an exterior open space leading
to a street.
Exits shall be so arranged that they may be reached
without passing through another occupied unit.
Economic Aspects Of Fire:
Losses & Expenditure…
• lives
• Property
• Use
• by Injury
• suppression
• prevention
• protection
• insurance
• research &
development
ESCAPE ROUTES:
There must be at least one escape route from
a. the main entrance door of every flat or maisonette
b. the door of every communal room
c. from every plant room.
An escape route must lead to a place of safety
a. directly
b. by way of a protected zone
c. by way of an access deck or access balcony
In case of under ground fire
Egress windows…
Windows Below Ground Level:
a)Sill height of window above floor: Not to exceed 1100 mm
b)Minimum opening area: 5.7 sq. ft.
c)Minimum opening height: 600 mm
d)Minimum opening width: 500 mm
HOW To ESCAPE THE FIRE…
Escaping with elevators.
Escaping through staircases.
Rescuing people by firemen and rescue
services.
Rescuing with a telescopic ladder.
Rescuing people through the windows.
Emergency escaping with the 'rescue
hose'
four distinct Stages:
Stage 1 – escape from the room or area of fire origin.
Stage 2 – escape from the compartment of origin via the circulation route to a protected stairway or an adjoining compartment offering refuge.
Stage 3 – escape from the floor of origin to the ground level.
Stage 4 – escape at ground level away from Building.
Means of escape from fire…
Time of evacuation
Travel distances
Capacity of Exits
Calculation of Exit Widths
Calculation of Minimum Number of Exits
Time of evacuation:
Class ‘A’ construction – 3 minutes
Class ‘B’ construction – 2.5 minutes
Class ‘C’ construction – 2 minutes
CAPACITY OF EXITS
The unit of exit width, used to measure the capacity of any
exit, shall be 500 mm. A clear width of 250 mm shall be
counted as an additional half unit. Clear widths less than 250 mm shall not be counted for exit width.
NOTE — The total occupants from a particular floor must evacuate within
2½ minutes for Type 1 construction, 1½ minutes for Type 2 construction
and 1 minute for Type 3 construction. Size of the exit door/exitway shall be
calculated accordingly keeping in view the travel distance as per Table
22.
Occupants per unit exit width shall be in accordance with
Table 21.
Travel Distance:
Places of Relative Safety A storey exit into a protected stairway or to the
lobby of a lobby approach stairway;
A door in a compartment wall or separating wall
leading to an alternative exit;
A door which leads directly to a protected stair or a
final exit via a protected corridor.
Calculation of Exit Widths
U = N / (40 x T)
Where: -
U = number of units required;
N = number of occupants;
40 = standard rate of flow – constant;
T = Flow time (i.e. 3 mins for Class ‘A’, 2.5 mins for
Class ‘B’ and 2 mins for Class ‘C’)
Calculation of Minimum Number of Exits E = U / 4 + 1
E = number of exits
U = number of units of exit width (from exit width
formula);
4 = size of largest exit permitted.
1 added to ensure there would always be at least
one unit.
Doorways Every exit doorway shall open into an enclosed stairway
or a horizontal exit of a corridor or passageway providing continuous and protected means of egress.
No exit doorway shall be less than 1 000 mm in width
except assembly buildings where door width shall be not
less than 2 000 mm. Doorways shall be not less than 2 000
mm in height.
Exit doorways shall open outwards, that is, away from
the room, but shall not obstruct the travel along any exit.
No door, when opened, shall reduce the required width of stairway or landing to less than 900 mm; overhead or
sliding doors shall not be installed.
Exit door shall not open immediately upon a flight of stairs;
a landing equal to at least the width of the door shall be
provided in the stairway at each doorway; the level of
landing shall be the same as that of the floor which it
serves.
Exit doorways shall be openable from the side which they
serve without the use of a key.
Mirrors shall not be placed in exit ways or exit doors to
avoid confusion regarding the direction of exit
Methods & Designs practiced
for escaping fire…
PRESSURISED STAIRCASE
functioninga) A Supply Air System designed
to blow into the protected
spaces a sufficient quantity of
air to maintain the required
pressure level or air velocity.
This will always be fan powered.
b) An Exhaust Air System to
enable the pressurising air to
escape from the unpressurised
areas of the building via the
fire floor.
This can be either a natural or fan
powered method.
Escape chute
system: Vertical escaping chute
Inclined chute
Single entry chute
Multiple entry chute
Residential chute
Vertical
chute:
Inclined chute
• prefer to slide to safety, rather than escape vertically.
Single
entry
chute &
multiple
entry
chute
Residential chute
• Weighing 13kgs / 28lbs the
frame can be carried from one
room to another, or from one
balcony to another on the
same level.
Hanging rope fire
escape:
Fire escaping stairs
A fire escaping stair is a special kind of emergency exit,
usually mounted to the outside of a building or occasionally inside but separate from the main areas of the building.
Escaping stairs..
• Drop ladder
Counterbalanced Stairs
• Gooseneck ladder
THANK YOU…