CODE OF PRACTICE FOR FIRE SAFETY OF BUILDINGS (GENERAL): EXIT
REQUIREMENTS AND PERSONAL HAZARD IS 1644: 1988 (Reaffirmed 2002)
1. SCOPE
1.1
This
standard covers requirements regarding fire safety of buildings with respect to
exit requirements and personal hazard.
2. EXIT REQUIREMENTS
2.1
Ample
provision for escape of population of a building when on fire is vital and all
routes should be constructed to ensure that the population reaches a place of
safety in the shortest period of time without undue hindrance by smoke, fumes,
debris and the like.
Every
building meant for human occupancy should be provided with exits sufficient to
permit safe escape of occupants, in case of fire or other emergency.
2.2 Types of Exits
2.2.1
An exit
may be a doorway, a corridor or passageway(s) to an internal staircase, or
external staircase, or to a verandah or terrace(s) which have access to the
street, or roof of a building, or a refuge area. An exit may also include a
horizontal exit leading to an adjoining building at the same level.
2.2.2
Lifts and
escalators should not be considered as exits.
2.3 General
2.3.1
In every
building, exits should comply with the minimum requirements except those not
accessible for general public use.
2.3.2
All exits
should be free of obstructions.
2.3.3
No
building should so altered as to reduce the number, width or protection of
exits to less than that required.
2.3.4
Exits
should be clearly visible and the routes to reach the exit should be clearly marked
and sign posted to guide the population of the floor concerned. Signs should be
painted with illuminated paint.
Note—This provision should
not apply to A-2 and A-4 occupancies up to 15 m in height (see 2.7.3 and 2.7.5).
2.3.5
Where
necessary, adequate and reliable illumination should be provided for exits.
2.3.6
Fire
check doors [ see IS : 3614 (Part 1)-1966* ] should at
appropriate places along the escape routes to prevent spread of fire and smoke
and particularly at the entrance to lifts and stairs where a ‘funnel or flue
effect’ may be created, including an upward spread of fire.
2.3.7
All exits
should provide continuous means of access to the exterior of a building or to
an exterior open space leading to a street.
2.3.8
Exits
should be so arranged that they may be reached without passing through another
occupied unit.
2.4
Occupant Load—For determining the exits requirement, the number of persons
within any floor area or the occupant load should be based on the actual number
of occupants, but in no case less than that specified in Table 1.
2.4.1
Mezzanine and Balcony—The occupant load of a mezzanine floor and balcony discharging to
a floor below should be added to that floor occupancy load thus established.
*Specification
for fire-check doors; Part 1 Plate, metal covered and rolling type.
TABLE 1 OCCUPANT LOAD (Clause 2.4)
|
Sl. No
|
Group of
Occupancy (see IS : 1641-1988*)
|
Occupant Load,
Floor Area in m3/Person
|
1.
|
Residential
|
(A)
|
12·5
|
2.
|
Educational
|
(B)
|
4
|
3.
|
Institutional
|
(C)
|
15†
|
4.
|
Assembly:
|
(D)
|
|
|
a)
|
With fixed or loose seats
and dance floors
|
|
0·6†
|
|
b)
|
Without seating
facilities including dining rooms
|
|
1·5‡
|
5.
|
Mercantile:
|
(F)
|
|
|
a)
|
street floor and sales
basement
|
|
3
|
|
b)
|
upper sale floors
|
|
3
|
6.
|
Business and industrial
|
(E and G)
|
10
|
7.
|
Storage
|
(H)
|
30
|
8.
|
Hazardous
|
(J)
|
10
|
* Code of practice for
the safety of buildings (general): General principles of fire grading and
classifications (first revision).
† Occupant load in dormitory portions of homes for the aged, orphanages,
insane asylums etc, where sleeping accommodation is provided, should be
calculated at not less than 7·5 m2 gross floor area/person.
‡ The gross floor area should include, in addition to the main assembly room
or space, any occupied connecting room or space in the same storey or in the
storeys above or below where entrance is common to such rooms and spaces and
they are available for use by the occupants of the assembly place. No
deductions should be made in the gross area for corridors, closets or other
subdivisions; the area should include all space serving the particular
assembly occupancy.
|
2.5 Capacity of Exits
2.5.1
The unit
of exit width, used to measure the capacity of any exit, should be 50 cm. A
clear width of 25 cm should be counted as an additional half unit. Clear widths
less than 25 cm should not be counted for exit width.
2.5.2
Occupants
per unit exit width should be in accordance with Table 2.
2.5.3
Horizontal Exit Allowance—When horizontal exit is provided in buildings of mercantile,
storage, industrial, business and assembly occupancies, the capacity per storey
per unit width of exit of stairways in Table 2 may be increased by 50 percent;
and in buildings of institutional occupancy, it may be increased by 100
percent.
2.6 Arrangement of Exits
2.6.1
Exits
should be so located that the travel distance on floor should not exceed the
distance given in Table 3.
2.6.2
The
travel distance to an exit from the dead end of a corridor should not exceed
half the distance specified in Table 3, except in educational, assemby and
institutional occupancies in which case it should not exceed 6 m.
TABLE 2 OCCUPANTS PER
UNIT EXIT WIDTH
(Clauses 2.5.2 and 2.5.3)
|
Sl No.
|
Group Of
Occupancy (See IS : 1641-1988*)
|
Number Of
Occupancy
|
|
|
Stairways
|
Ramps
|
Doors
|
|
|
(1)
|
(2)
|
(3)
|
(4)
|
(5)
|
|
|
1.
|
Residential (A)
|
25
|
50
|
75
|
|
|
2.
|
Educational (B)
|
25
|
50
|
75
|
|
|
3.
|
Institutional (C)
|
25
|
50
|
75
|
|
|
4.
|
Assembly (D)
|
40
|
50
|
60
|
|
|
5.
|
Business (E)
|
50
|
60
|
75
|
|
|
6.
|
Mercantile (F)
|
50
|
60
|
75
|
|
|
7.
|
Industrial (G)
|
50
|
60
|
75
|
|
|
8.
|
Storage (H)
|
50
|
60
|
75
|
|
|
9.
|
Hazardous (J)
|
25
|
30
|
40
|
|
|
*Code of practice for
safety of buildings (general): General principles of fire grading and
classification (first revision).
|
|
|
2.6.3
Whenever
more than one exit is required for any room, space or floor of a building,
exits should be placed as remote from each other as possible and should be
arranged to provide direct access in separate directions from any point in the
area served.
TABLE 3 TRAVEL DISTANCE
FOR OCCUPANCY AND TYPE OF CONSTRUCTION
(Clauses 2.6.1 and 2.6.2)
|
Sl No.
|
Group of
Occupancy (see IS : 1641-1988*)
|
Maximum Travel
Construction (see IS : 1642-1988 †)
|
|
|
Type 1 and 2
|
Type 3 and 4
|
(1)
|
(2)
|
(3)
|
(4)
|
|
|
m
|
m
|
1.
|
Residential (A)
|
22 5
|
22·5
|
2.
|
Educational (B)
|
22·5
|
22·5
|
3.
|
Institutional (C)
|
22·5
|
22·5
|
4.
|
Assembly (D)
|
30·0
|
30·0
|
5.
|
Business (E)
|
30·0
|
30·0
|
6.
|
Mercantile (F)
|
30·0
|
30·0
|
7.
|
Industrial (G)
|
45·0
|
30·0
|
8.
|
Storage (H)
|
30·0
|
30·0
|
9.
|
Hazardous (J)
|
22·5
|
22·5
|
*Code of practice for
fire safety of builders (general): General principles of fire grading and
classification (first revision).
†Code of practice for fire safety of buildings (general): Details of
construction (first revision).
|
2.7 Number of Exists
2.7.1
General Requirement—All buildings which are more than 15 m in height and all
buildings used as educational (B), assembly (D), institutional (F), industrial
(G), Storage (H), and hazardous (J) occupancies and mixed occupancies with any
of the aforesaid occupancies, having area more than 500 m2 on
each floor should have a minimum two staircases. They should be of enclosed
type; at least one of them should be on external walls of buildings and should
open directly to the exterior, interior open space or to an open place of
safety. Further, the provision, or otherwise of alternative staircase should be
subject to the requirements of travel distance being complied with.
2.7.2
Rooming Houses of Residential Buildings (A-1)—Every sleeping room above
the street floor should have access to two separate means of exit, at least one
of which should consist of an enclosed interior stairway or an exterior
stairway, or a fire escape or horizontal exit, all so arranged as to provide a
safe path of travel to the outside of the building without traversing any
corridor or space exposed to an unprotected vertical opening. Any sleeping room
below the street floor should have direct access to the outside of the
building.
2.7.3
One or Two Family Private Dwellings or Residential Building (A-2)
2.7.3.1
For more
than two rooms, every occupied room excluding areas used solely for storage,
should have at least two means of exit, at least one of which should be a door
or a stairway providing a means of unobstructed travel to the outside of the
building or street or grade level and not more than one of which may be a
window. No room or space should be occupied which is accessible only be a
ladder, folding stairs or through a trap door.
2.7.3.2
All
locking devices which would impede or prohibit exit, such as chain type bolts,
limited opening sliding type locks and burglar locks which are not disengaged
easily by quick-releasing catches, should be prohibited. All closet door
latches should be such that even children may open the doors from inside. All
bathroom door locks or fasteners should be designed to permit the opening of
the locked or closed door from the outside in an emergency without the use of a
special key. Every below-street-level sleeping room should have direct access
to the outside of the building.
2.7.4
Dormitories (A-3)—All dormitories, except those mentioned
in 2.7.6 should have exits so arranged that from any sleeping
room or open dormitory sleeping area, there should be access to two separate
and distinct exits in different directions with no common path of travel unless
the room or space is subject to occupancy by not more than 10 persons and has a
door opening directly to the outside of the building at street or grade level,
or to an outside stairway in which case one means of exit may be accepted.
2.7.5 Apartment House (A-4)
2.7.5.1
Every
individual living unit should comply with the requirements for occupancy
subdivision A-2 in respect of exit (see 2.7.3).
2.7.5.2
Every
living unit should have access to at least two separate exits which are remote from
each other and are reached by travel in different directions except that a
common path of travel may be permitted for the first 6 m (that is, a dead-end
corridor up to 6 m long may be permitted) provided that single exit may be
permitted under any of the conditions given in 2.7.5.3.
2.7.5.3
Any
building not more than two storeys in height with no basement, or in case there
is a basement and with street floor level not more than 2·5 m above ground at
any point next to the building, excluding driveways, not more than 10 percent
of the perimeter should be subject to the condition that the access to the
basement is only from the exterior of the building if the basement contains a
heating plant, group storage, incinerator room or paint shop or other hazardous
occupancy.
2.7.5.4
At least
half of required exits should discharge direct to the outside of the buildings;
any other exit should be the same as required for the hotels (see 2.7.6).
2.7.6 Hotels (A-5)
2.7.6.1
Not less
than two exits, as remote from each other as practicable, should be accessible
from every floor, including basements occupied for hotel purposes, except as a
single exit as permitted in 2.7.6.2 below. Exits and ways of
access thereto should be so arranged that they are accessible in at least two
different directions from every point in any open area, or from any room door.
2.7.6.2
Any room
or section with an outside door at street or grade level may have such outside
door as a single exit provided no part of the room or area is more than 15 m
from the door measured along the natural path of travel.
2.7.6.3
Where
stairways or other exits serve two or more upper floors, the same stairway or
other exit required to serve any one upper floor may also serve other upper
floors except that no inside open stair-way or ramp may serve as a required
egress facility from more than one floor.
Note—Under this provision,
if the second and third floors were each required to have three stairways, the
second floor may use the stairways serving the third floor so that the total
number of stairways required is three, and not six.
2.7.7 Basement Exits for Residential Buildings (A)
2.7.7.1
Basements
occupied for hotel purposes should have exits arranged in accordance with 2.7.6
2.7.7.2
Basement
exits should be sufficient to provide for the capacity of the basement as
determined in accordance with 2.3 and in no case should there
be less than two independent basement exits.
2.7.7.3
Basements
or sub-basements not open to the public and used only for heating equipment,
storage and service operations (other than kitchens which are considered part
of the hotel occupancy) should have exits appropriate to the actual occupancy,
in accordance with applicable provisions or in case of mixed occupancy where
there may be doubt as to which other section is applicable, such basements
should have exits determined on the basis of lesser exit capacity.
2.7.8 Educational (B)
2.7.8.1
At least
two separate exits are available in every floor area. Exits should be as remote
from each other as practicable and so arranged that there are no pockets or
dead ends of appreciable size in which occupants may be trapped.
2.7.8.2
Every
room with a capacity of over 100 persons in area should have at least two
doorways as remote from each other as practicable. Such doorways should provide
access to separate exits but may open upon a common corridor leading to
separate exits in opposite directions.
2.7.8.3
Exterior
doors should be operated by bars or some other panic hardware device except
that doors leading from classroom directly to the outside may be equipped with
the same type of lock as is used on classroom doors leading to corridor with no
provision whatsoever for locking against egress from the classroom.
2.7.9 Institutional (C)
2.7.9.1
In buildings
or sections occupied by bedridden patients where the floor area is over 280 m2,
facilities should be provided to move patients in hospital beds to the other
side of a smoke barrier from any part of such building or section not directly
served by approved horizontal exits or exits from the first floor (Floor 2) of
a building to the outside.
2.7.9.2
Not less
than two exits of one or more of the following types should be provided for
every floor, including basement, of every building or section:
- Doors leading directly outside the
building,
- Stairways,
- Ramps, and
- Horizontal exits.
2.7.9.3
All
required exits which serve as egress from hospital or infirmary sections should
be not less than 150 cm in clear width, including patient bedroom doors, to
permit transportat on of patients on beds, litters or mattresses. The minimum
widths of corridors serving patients bedrooms in building should be 240 cm.
2.7.9.4
Revolving
doors should not be counted as required exits and should not be installed,
except in situations, such as revolving doors at a main entrance where they are
not subject to emergency exit use by patients.
2.7.9.5
Elevators
constitute a desirable supplementary facility but are not counted as required
exits.
2.7.9.6
Each
storey in which 35 or more patients are housed should be divided into at least
two compartments by smoke barriers and the Authority may require storeys
housing a lesser number of patients to be divided into compartments when, in
its judgement, such division is essential for the protection of the patients.
2.7.9.7
Doors in
smoke barriers should be so installed that these may normally be kept in open
position but will close automatically or may be released manually to
self-closing action. Corridor door openings in smoke barriers should not be
less than 150 cm in width. Provision should also be made for double swing
single/double leaf type door.
2.7.9.8
Exits and
other features for penal and mental institutions, and custodial institutions
should be the same as specified for hospitals, in so far as applicable.
Reliable means should be provided to permit the prompt release of inmates from
any locked section in case of fire or other emergency.
2.7.9.9
Wherever
any inmates are confined in any locked rooms or spaces, adequate guards or other
personnel should be continuously on duty or immediately available to provide
for release of inmates or for such other action as may be indicated in case of
fire or other emergency.
2.7.9.10
No
building constructed in whole or in part of combustible materials should be
used to combine inmates in cells or sleeping quarters unless automatic
sprinkler protection is provided.
2.7.9.11
All
buildings or sections of buildings penal and mental institutions used for
manufacturing, storage or office purposes should have exits in accordance with
the provisions of occupancies.
2.7.10 Assembly Buildings (D)
2.7.10.1
Every
place of assembly, every tier or balcony, and every individual room used as a
place of assembly should have exits sufficient to provide for the total
capacity thereof as determined in accordance with 2.7.7.
2.7.10.2
Every
place of assembly of subdivision D-l should have at least four separate exits
as remote from each other as practicable.
2.7.10.3
Every
place of assembly of subdivision D-2 should have at least two separate exits
remote from each other as practicable and if of capacity over 600, at three
exits should be provided with each exit not less than of 2 unit widths.
2.7.10.4
Every
place of assembly of subdivisions D-3, D-4 and D-5 should have at least two
means of exit, consisting of separate exits or doors leading to corridor or
other spaces giving access to two separate and independent exits in different
directions, except that for places of assembly having a capacity of less than
100 persons, one 2-unit doorway may be permitted in rooms where no part of the
room is more than 15 m from the doorway, measured along the line of travel, and
the doorway leads directly outside the building at grade level or leads to a
corridor or other space giving access to two separate and independent exits.
2.7.10.5
Clear
aisles not less than 1·2 m in width should be formed at right angles to the
line of seating in such number and manner that no seat should be more than
seven seats away from an aisle. Rows of seats opening on to an aisle at one end
only should have not more than seven seats. Under the conditions where all
these aisles do not directly meet the exit doors, cross-aisles should be
provided parallel to the line of seating so as to provide direct access to the
exit, provided that not more than one cross-aisle for every 10 rows should be
required. The width of cross aisles should be a minimum of 1 m. Steps should
not be placed in aisles to overcome differences in levels unless the gradient
exceeds 1 in 10.
2.7.10.6
The
fascia of boxes, balconies and galleries should have substantial railings not
less than 65 cm high above the floor. The railings at the end aisles extending
to the fascial should be not less than 75 cm high for the width of the aisle or
90 cm high at the foot of steps.
2.7.10.7
Cross-aisles
except where the backs of seats on the front of the aisle project 60 cm or more
above the floor of the aisle, should be provided with railings not less than 90
cm high.
2.7.10.8
No
turnstiles or other devices to restrict the movement of persons should be
installed in any place of assembly in such a manner as to interfere in any way
with the required exit facilities.
2.7.10.9
In
theatres and similar places of public assembly where persons are admitted to
the building at a time when seats are not available for them and are allowed to
wait in a lobby or similar space until seats are available, such use of lobby
or similar space should not encroach upon the required clear width of exits.
Such waiting should be restricted to areas separated from the required exitways
by substantial permanent partitions or fixed rigid railing not less than 105 cm
high. Exits should be provided for such waiting spaces on the basis of one
person for each 0·3 m3 of waiting space area. Such exits should
be in addition to the exits specified for the main auditorium area and should
conform in construction and arrangement to the general rules of exits given
above.
2.7.10.10
No
display or exhibit should be so installed or operated as to interfere in any
way with access to any required exit, or with any required exit sign. All
displays or exhibits of combustible material or construction and all booths and
temporary construction in connection with it should be so limited in
combustibility or protected as to avoid any undue hazard of fire which might
endanger occupants before they have opportunity to use the available exits.
2.7.10.11
No
mirrors should be placed in or adjacent to any exitway in such a manner as to
confuse the direction of the exit.
2.7.10.12
Places of
assembly in buildings of other occupancy may use exits common to the place of
assembly and other occupancy. Provided the assembly area and other occupancy
are considered separately, each has exits sufficient to meet the requirements.
2.7.10.13
Exits
should be sufficient for simultaneous occupancy of both the places of assembly
and other parts of the building, unless the conditions are such that
simultaneous occupancy will not occur.
2.7.10.14
For any
place of assembly under subdivision D-1, at least half the required means of
exits should lead directly outdoors or through exitways completely separated
from exits serving other parts of the building.
2.7.11 Business (E)
2.7.11.1
In the
case of mezzanines or balconies open to the floor below, or other unprotected
vertical openings between floors, the population of the mazzanine or other
subsidiary floor level should be added to that of the main floor for the
purpose of determining the required exits, provided, however, that in no case
should the total number of exits, units be less than that required if all the
vertical openings were enclosed.
2.7.11.2
Not less
than two exits should be provided for every floor, including basements occupied
for office purposes or uses incidental thereto.
2.7.12 Mercantile (F)
2.7.12.1
In the
case of mezzanines or balconies open to the floor below, or other unprotected
vertical openings between floors, the population or area of the mezzanine or
other subsidiary floor level should be added to that of the main floor for the
purpose of determining the required exits, provided, however, that in no case
should the total number of exits units be less than that required if all
vertical openings were enclosed.
2.7.12.2
At least
two separate exits should be accessible from every part of every floor,
including basements; such exits should be as remote from each other as
practicable and so arranged as to be reached by different paths of travel in
different directions except that a common path of travel may be permitted for
the first 15 m from any point.
2.7.13 Industrial (G)
2.7.13.1
Not less
than two exits should be provided for every floor or section, including
basements used for industrial purposes or uses incidental thereto.
2.7.13.2
In
buildings used for aircraft assembly or other occupancy requiring undivided
floor areas so large that the distance from points within the area to the
nearest outside walls where exit doors could be provided are in excess of 45 m,
requirements for distance to exits may be satisfied by providing stairs leading
to exit tunnels or to overhead passageways. In cases where such arrangements
are not practicable, permit other exit arrangements for one storey buildings
with distance in excess of the maximum distances specified in 2.6.
If completely automatic sprinkler protection is provided and if the heights of
ceiling curtain boards and roof ventilation are such as to minimize the
possibility that employees will be overtaken by the spread of fire or smoke
within 180 cm of the floor level before they have time to reach exits,
provided, however, that in no case may the distance of travel to reach the
nearest exit exceed 120 m where smoke venting is required as a condition for
permitting distances of travel to exits in excess of the maximum otherwise
allowed.
2.7.13.3
Basements
used only for storage, heating and other service equipment, and not subject to
industrial occupancy should have exits in accordance with the requirements of
Group H occupancies.
2.7.13.4
The
following exceptions should apply to special purpose industrial occupancies:
- Exits need be provided only for
the persons actually employed; spaces not subject to human occupancy
because of the presence of machinery or equipment may be excluded from
consideration.
- Where unprotected vertical
openings are necessary to manufacturing operations, these may be permitted
beyond the limits specified for industrial occupancy provided every floor
level has direct access to one or more enclosed stairways or other exits
protected against obstruction by any fire in the open areas connected by
the unprotected vertical openings or smoke therefrom.
2.7.13.5
The
following exceptions should apply to high hazard industrial occupancies:
- Exits should be so located that it
will not be necessary to travel more than 22· 5 m from any point to reach
the nearest exit.
- From every point in every floor
area, there should at least be two exits accessible in different
directions; where floor areas are divided into rooms, there should be at
least two ways of escape from every room, however small, except toilet
rooms, so located that the points of access thereto are out of or suitably
shielded from areas of high hazard.
- In addition to types of exits for
upper floors specified for Group G occupancies, slide escapes may be used
as required exits for both new and existing buildings.
2.7.14 Storage (H)
2.7.14.1
Every
building or structure used for storage, and every section thereof considered
separately, should have access to at least one exit so arranged and located as
to provide a suitable means of escape for any person employed therein and in
any room or space exceeding 1 400 m2 gross area, or where more
than 10 persons may be normally present, at least two separate means of exit
shall be available, as remote from each other as practicable.
2.7.14.2
Every
storage area should have access to at least one means of exit which can be
readily opened. This should not be subject to locking so long as any persons
are inside and should not depend on power operation.
2.7.14.3
The
following special provisions should apply to parking garages of closed or open
type, above or below ground but not to mechanical parking facilities where
automobiles move into and out of storage mechanically which are not normally
occupied by persons and thus require no exit facilities. Where repair
operations are conducted, the exits should comply with the requirements of
Group G occupancies in addition to compliance with the following:
- Where both parking and repair
operations are conducted in the same building, the entire building should
comply with the requirements for Group G occupancies unless the parking
and repair sections are effectively separated by separation walls.
- Every floor of every closed
parking garage should have access to at least two separate means of exit
so arranged that from any point in the garage, the paths of travel to the
two means of exit should be in different directions, except that a common
path of travel may be permitted for the first 15 m from any point.
- On the street floor, at least two
separate exit doors should be provided except that any opening for the
passage of automobiles may serve as a means of exit provided no door or
shutter is installed thereon. Street floor exits in closed garages should
be so arranged that no point in the area is more than 30 m from the
nearest exit, or 45 m in the case of garages protected by automatic
sprinklers, distance being measured along the natural path of travel.
- On floors above the street, at least
two means of exit should be provided, one of which should be an enclosed
stairway. The other means of egress may be a second exit of any of the
types, or in a ramp type garage with open ramps not subject to closure,
the ramp may serve as the second means of exit.
- Upper floor exits in closed
garages should be so arranged that no point in the area should be more
than 30 m from the nearest exit other than a ramp on the same floor level,
or 45 m in the case of garages protected by automatic sprinklers.
- On floors below the street (either
basement or outside underground garages), at least two exits should be
provided, not counting any automobile ramps except that for garages
extending only one floor level below the street, a ramp leading direct to
the outside may constitute one required means of exit. In garages below
street level, exits should be so arranged that no part of the area should
be more than 30 m from the nearest stair exit.
- If any gasoline pumps are located
within any closed parking garage, exits should be so located that travel
away from the gasoline pump in any direction should lead to an exit, with
no dead-end in which the occupants might be trapped by fire or explosion
at any gasoline pump. Such exit should lead to the outside of the building
on the same level, or downstairs; no upward travel should be permitted
unless direct outside exits are available from the floor and any floor
below (as in the case of a basement garage where the grade is one storey
or more lower at the rear than at the street).
2.7.14.4
Exits
from aircraft hangars (storage or servicing areas) should be provided at
intervals of not more than 45 m on all exterior walls of aircrafts hangars.
There should be a minimum of two exits serving each aircraft storage
or servicing area. Horizontal exits through interior fire walls should be
provided at intervals of not more than 30 m. ‘Dwarf or’ ‘smash’ doors in doors
accommodating aircraft may be used to comply with these requirements. All doors
designated as exits should be kept unlocked in the direction of exit travel
while the area is occupied.
2.7.14.5
Exits
from mezzanine floors in aircraft storage or servicing area should be so
arranged that the maximum travel to reach the nearest exit from any point on
the mezzanine should not exceed 22’5 m. Such exits should lead directly to a
properly enclosed stairwell discharging directly to the exterior or to a
suitably cut-off area or to outside fire escape stairs.
2.7.14.6
The
following provisions should apply to grain elevators:
- There should at least be one stair
tower from basement to first floor and from first floor to top floor of
the workhouse enclosed in a dust-tight non-combustible shaft;
- Non-combustible doors of
self-closing type should be provided at each floor landing;
- An exterior fire escape of the
stair or basket ladder type should be provided from the roof of the
workhouse to the ground level or to the roof of an adjoining annexe with
access from all floors above the first; and
- An exterior fire escape of either
the stair or basket ladder type should be provided from the roof of each
storage annexe to the ground level.
2.7.14.7
Every
area used for storage of hazardous commodities should have an exit within 22·5
m of any point in the area where persons may be present or 30 m where automatic
sprinkler protection is provided.
2.7.15
Hazardous (J)—Same as in 2.7.13.5.
2.8 Doorways
2.8.1
Every
exit doorway should open into an enclosed stairway, or horizontal exit of a
corridor, or passageway providing continuous and protected means of egress.
2.8.2
No exit
doorway should be less than 100 cm in width. Doorways should be not less than
200 cm in height.
2.8.3
Exit
doorways should open outwards, that is, away from the room but should not
obstruct the travel along any exit. No door, when opened, should reduce the
required width of stairway or landing to less than 90 cm; overhead or sliding
door should not be installed.
Note—In the case of
buildings where there is a central corridor, the doors of rooms should open
inwards to permit smooth flow of traffic in the corridor.
2.8.4
Exit door
should not open immediately upon a flight of stairs, a landing equal to at
least the width of the door should be provided in the stairway at each doorway;
the level of landing should be the same as that of the floor which it serves.
2.8.5
Exit
doorways should be openable from the side which they serve without the use of a
key.
2.8.6 Revolving Doors
2.8.6.1
Revolving
doors should not be used as required exits except in residential, business and
mercantile occupancies but should not constitute more than half the total
required door width. In mercantile buildings where there is possibility of
congregation of a large number of people (more than 200), revolving doors
should not be permitted.
2.8.6.2
Where the
revolving door provided are completely made of glass (plate glass), a red
circle or emblem or logo at 1·5 m level above sill should be painted on the
glass. The thickness of the glass should not be not less than 12 mm.
2.9 Corridors and
Passageways
2.9.1
Exit
corridors and passageways should be of width not less than the aggregate
required width of exit doorways leading from them in the direction of travel to
the exterior.
2.9.2
Where
stairways discharge through corridors and passageways, the height of corridors
and passageways should be not less than 2·4 m.
2.10 Internal Staircases
2.10.1
Interior
stairs should be constructed of non-combustible materials throughout.
2.10.2
Interior
staircase should be constructed as a self-contained unit with an external wall
constituting at least one of its sides and should be completely enclosed.
2.10.3
A
staircase should not be arranged round a lift shaft unless the latter is
totally enclosed by a material of fire-resistance rating as that for the type
of construction itself.
2.10.4
Hollow
combustible construction should not be permitted.
2.10.5
No gas
piping should be laid in the stairway.
2.10.6
Notwithstanding
the detailed provision for exits given above the following minimum width should
be provided for staircases:
a)
|
Residential buildings
(dwellings)
|
1·0 m
|
Note—For row housing with
2 storeys, the width should be 0·75 m.
|
b)
|
Residential hotel
buildings
|
1·5 m
|
c)
|
Assembly buildings like
auditorium, theatres and cinemas
|
1·5 m
|
d)
|
Educational buildings:
|
|
|
i) Up to 24 m in height
|
1·5 m
|
|
ii) More than 24 m in
height
|
2·0 m
|
e)
|
Institutional buildings
like hospitals:
|
|
|
i) Up to 10 beds
|
1·5 m
|
|
ii) More than 10 beds
|
2·0 m
|
f)
|
All other buildings
|
1·5 m
|
2.10.7
The
minimum width of tread without nosing should be 25 cm for internal staircase of
residential buildings. This should be 30 cm for assembly, educational,
institutional, business and other buildings. The treads should be constructed
and maintained in a manner to prevent slipping.
2.10.8
The
maximum height of riser should be 19 cm for residential buildings and 15 cm for
other buildings and the number should be limited to 15 per flight.
2.10.9
Hand
rails should be provided at a minimum height of 100 cm and not exceeding 120 cm
to be measured from the base of the middle of the treads to the top of the hand
rails. Further, the gap between the two verticals should not exceed 30 cm. This
gap should be reduced to 15 cm where children are likely to use the staircase.
2.10.10
The
number of people in between floor landings in staircase should not be less than
the population on each floor for the purpose of design of staircase.
2.11 Fire Escapes or
External Stairs
2.11.1
Fire
escapes should not be taken into account in calculating the evacuation time of
a building.
2.11.2
All fire
escapes should be directly connected to the ground.
2.11.3
Entrance
to the fire escape should be separate and remote from the internal staircase.
2.11.4
Care
should be taken to ensure that the wall opening or window opens on to or close
to a fire escape.
2.11.5
The route
to the fire escape should be free of obstructions at all times.
2.11.6
The fire
escape should be constructed of non-combustible materials, and any doorway
leading to the fire escape should have the required fire resistance.
2.11.7
No
staircase, used as a fire escape, should be inclined at an angle greater than
45° to the horizontal.
2.11.8
Fire
escape stairs should have straight flight not less than 75 cm wide with 20 cm
treads and risers not more than 19 cm. The number of risers should be limited
to 15 per flight.
2.11.9
Hand
rails should be of a height not less than 100 cm and not exceeding 120 cm.
2.11.10
Spiral Fire Escape—The use of spiral staircase should be limited to occupant load
and to a building not exceeding 9 m in height unless they are connected to
platforms, such as balconies and terraces to allow escapees to pause.
2.11.11
Spiral
fire escape should be not less than 150 cm in diameter and should be designed
to give adequate headroom.
2.12
Roof Exit—In all buildings over three storeys in height where the slope of
the roof is less than 20 degrees, direct access to the roofs should be provided
from the street by means of a stairway. Where roofs are used as roof gardens or
for other habitable purposes, sufficient stairways should be extended to them
to provide necessary exit facilities required for such an occupancy.
Note—This does not apply to
A-2 and A-4 occupancies up to 15 m height.
2.13 Horizontal Exits
2.13.1
The width
of horizontal exit should be the same as for the exit doorways (see 2.8).
2.13.2
A
horizontal exit should be equipped with at least one fire door of self-closing
type.
2.13.3
Floor
area on the opposite or refuge side of a horizontal exit should be sufficient
to accommodate occupants of the floor areas served, allowing not less than 0·3
m2/person. The refuge area into which a horizontal exit leads should
be provided with exits adequate to meet the requirements given in this
standard. At least one of the exits should lead directly to the exterior of
building or to a street.
2.13.4
Where
there is a difference in level between connected areas for horizontal exits,
ramps, not more than 1 in 10 in slope should be provided; steps should not be
used.
2.13.5
Doors in
horizontal exits should be openable at all times from both sides.
2.14
Fire Tower—Fire towers are the preferred type of escape route for storeyed
buildings and their application should be considered as the safest route for
escape. Their number, location and size should depend on the building
concerned, and its associated escape routes.
2.14.1
In every
mercantile, industrial, business, assembly buildings other than theatres,
institutional and residential buildings, over 6 storeys or 25 m in height, at
least one required means of egress should be a fire tower.
2.14.2
The
enclosure of fire towers should be constructed of walls with a 4 h
fire-resistance rating without openings other than the exit doorways with
platform, landings and balconies of not less than 3 h fire-resistance rating.
2.15 Ramps
2.15.1
Ramps
should comply with all the applicable requirements for stairways regarding
enclosure, capacity and limiting dimensions except where specified for special
uses and occupancies.
2.15.2
The slope
of a ramp should not exceed 1 in 10. In certain cases, steeper slopes may be
permitted but in no case greater than 1 in 8.
2.15.3
For all
slopes exceeding 1 in 10 and wherever the use is such as to involve danger of
slipping, the ramp should be surfaced with approved non-slipping material.
