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 SPECIFICATIONS OF PARTS OF BUILDINGS - CHAPTER -VI

Table – 14
AREA AND DIMENSION OF VENTILATION SHAFT

Height of buildings in m.
Cross sectional area of ventilation shaft in sq.m.
Minimum side of shaft in m.
Up to 12
2.8
1.2
Up to 18
4.0
1.5
Up to 24
5.4
1.8

In ventilation shafts, in high rise building mechanical system shall be installed. Further such ventilation shafts shall be adequately accessible for maintenance.

6.12.3 In residential hotels, where attached toilets are provided with mechanical ventilation system installed as per aforesaid Regulation the Competent Authority may relax the size of the ventilation shaft.

6.13 PARAPET:

Parapet walls and handrails provided on the edges of roof terraces, balcony etc. shall have a clear height not less than 1.15 m. from the finished floor level and not more than 1.30 m. above the unfinished floor level.

6.14. EXIT REQUIREMENT:

6.14.1 The following general requirements shall apply to exits:

6.14.1.1 Any building meant for human occupation shall be provided with exits sufficient to permit safe escape of occupants in case of fire or other emergencies. An exit may be doorway, corridor, passage leading to an internal staircase or external staircase, ramps or a verandah and/or terraces that have access to the street or to the roof of a building. An exit may also include a horizontal exit leading to an adjoining building at the same level.

6.14.1.2 In every part of the building except those, which are not accessible for general public use, exits shall comply with the minimum requirements of this part. Requisite number and size of exits shall be provided, based on the population in each room and floor based on the occupant load capacity of exits, travel distance and height of buildings as per these Regulations.

6.14.1.3 Non residential component in a building partially having residential use shall have independent exit.

6.14.1.4 All exits shall provide continuous means of egress to the exterior of a building or to an exterior open space leading to a street.

6.14.1.5 Exits shall be clearly visible and the routes to reach the exit shall be clearly marked and sign posted to guide the people to the floor concerned;

6.14.1.6 All exit ways shall be properly illuminated.

6.14.1.7 All exits shall be free of obstructions. Exits shall be so located that the total travel distance on the floor shall not exceed 22.5 m. for residential, educational, institutional and hazardous occupancies and 30 m. for assembly, business, mercantile, industrial and storage occupancies. Whenever more than one exit is required for a floor of a building, exits shall be placed as remote from each other as possible. All the exits shall be accessible from the entire floor area at all floor levels.

6.14.1.8 Fire fighting equipment where provided along with the exits shall be suitably located and clearly marked but must not obstruct the exit way and yet there should be clear indication about its location from either side of the exit way.

6.14.1.9 Alarm devices shall be installed for special buildings above 16 m. in height in conformity with Regulation 14 of Appendix XVIII to ensure prompt evacuation of the population concerned through the exits.

6.14.1.10 Exits shall be so arranged that they may be reached without having to pass through another occupied unit except in the case of residential buildings.

6.14.1.11 Exits for all public assembly and institutional buildings shall have provision of ramp with handrails at 75 cm height to facilitate movement of physically handicapped persons.

6.14.1.12 No building shall be altered so as to reduce the number, width of exits to less than that required.

Note 1: The travel distance to an exit from dead end of a corridor shall not exceed half the distance specified above.

Note 2: Lifts and escalators shall not be considered as exits.

6.14.2 Occupant load –

The population in rooms, areas of floors shall be calculated based on the occupant load given below.

TABLE - 15
OCCUPANT LOAD

 Sr. No.
Group of Occupancy
Occupant Load as Gross Area in sq.m. /person. *
1
Residential
12.5
2
Educational
4.0
3
Institutional
15.0
4.
Assembly
 
(i) With Fixed or Loose Seats and Dance floors.
0.6 **
(ii) Without seating facilities, including dining rooms.
1.5 ***
5
Mercantile
 
I) Street Floor and Sales basement
3.0
Ii) Upper Sale Floors
 6.0
6
Business and Industrial
10.0
7
Storage
30.0
8
Hazardous
10.0

* The gross area shall mean plinth area or covered area.

** Occupant load in dormitory portions of homes for the aged, orphanages, insane asylums, etc. where a living accommodation is provided, shall be calculated at not less than 7.5 sq.m. gross area/person.

*** The gross area shall include in addition to the main assembly room or spaces, any occupied connecting room or spaces 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. Area under corridors, toilets, etc shall not be taken into account while computing the occupant load.

6.14.3 Capacity of exits -

6.14.3.1 The capacity of exits (doors and stairways) indicating the number of persons that could be safely evacuated through a unit exit width of 50 cm. shall be as given below. 

                                       TABLE – 16 
                   OCCUPANT LOAD PER UNIT EXIT WIDTH

Sr. No.
Group of
Occupancy
Stairways
Occupant load
1.
Residential
25
75
2.
Educational
25
75
3.
Institutional
25
75
4.
Assembly
60
90
5.
Business
50
75
6.
Mercantile
50
75
7.
Industrial
50
75
8.
Storage
50
75
9.
Hazardous
25
40


6.14.3.2 For all special buildings where two staircases are required, at least one of them shall be on the external wall of building and shall open directly to the exterior, interior open space or to any open place of safety. It shall preferably be of an enclosed type.


6.15 DOORWAY:

6.15.1 Every exit doorway shall open into an enclosed stairway, a horizontal exit, or a corridor or passageway providing continuous and protected means of egress.

6.15.2 No exit doorway shall be less than 100 cm. in width. Doorways shall not be less than 200 cm. in height. Doorways for bathrooms, water closet, stores etc. shall be not less than 75 cm. wide - (masonry opening) provided further that the clear opening between the frame shall not be less than 65 cm.

6.15.3 Exit doorways, including special security doors shall open outwards, that is, away from the room but shall not obstruct the travel along any exit corridor, landing etc. No door, when opened, shall reduce the required width of stairway or landing to less than 90 cm. Overhead or sliding doors shall not be installed.

6.15.4 Exit door shall not open immediately upon a flight of stairs. A landing of at least 1.5 m. width shall be provided in the stairway at each doorway. The level of landing shall be the same as that of the floor it serves.

6.15.5 Revolving Doors:

Revolving doors may be used as required exit only in business and mercantile occupancies. When revolving doors are considered as required exit way the following assumptions shall be made: -

I) Each revolving door shall be credited one half unit exit width, and

ii) Revolving doors shall not be located at the flight of a stairway. Any stairway served by a revolving door shall discharge through a lobby or foyer.

6.16 CORRIDOR:

(I) The minimum width of a corridor shall not be less than 1.0 m. in the case of 2 storeyed row housing residential building and in the case of other buildings, actual width shall be calculated based on the provisions of Table-17.

(ii) In case of more than one main staircase of the building, inter-connected by a corridor or other enclosed spaces, there shall be at least one smoke-stop door across the corridor or enclosed spaces between the doors in the enclosing walls of any two staircases.


6.17 STAIRCASE

6.17.1 Minimum width of the staircase -

6.17.1.1 For various occupancies, width of a stair shall be as under:

TABLE - 17
MINIMUM WIDTH OF COMMON STAIRWAYS/CORRIDORS FOR VARIOUS OCCUPANCIES.

Sr. No.
Type of Occupancy
Minimum width of staircase / stairway / corridor in m
Minimum width of landing / mid landing in m
1.
Residential Buildings -
 
 
(i) General
1.20
1.50
(ii) Row Housing and Bungalows (2 storeys)
0.75
0.75
(iii) Hotels
1.50
1.50
2.
Educational and Medical bldgs. -
2.00
2.00
3.
Institutional buildings -
2.00
2.00
4.
Assembly buildings
2.00
2.00
5.
Mercantile, business, industrial, storage, hazardous buildings.
1.50
1.50

6.17.1.2 Notwithstanding anything contained in the above table, if the length of the closed corridor/passage exceeds 7.5 m in the case of a residential building, then the width of the corridor/passage shall increase by 1/5th of the incremental length. Similarly, in the case of non-residential buildings, if the length of closed corridor/passage exceeds 12 m., then the width of the corridor/passage shall increase by 1/8th of the incremental length. Provided that the maximum width of such closed corridor shall not exceed 3.0m.
(Modified as per M-12)

6.17.2 Other requirements of staircase -

6.17.2.1 Common stairs shall be constructed of non-combustible materials throughout.

6.17.2.2 Interior stairs shall be constructed as a self-contained unit with at least one side adjacent to an external wall and shall be completely enclosed.

6.17.2.3 A staircase shall not be arranged around a lift shaft unless the latter is entirely enclosed by a material of fire resistance rating as that for the type of construction itself.

6.17.2.4 Hollow combustible construction shall not be permitted.

6.17.2.5 The minimum width of treads without nosing shall be 25 cm. for an internal staircase for residential buildings. In the case of other buildings, the minimum tread shall be 30 cm. The treads shall be constructed and maintained in a manner to prevent slipping.

6.17.2.6 The maximum height of riser shall be 19 cm. in residential buildings and 15 cm. in other buildings. They shall be limited to 12 per flight. For Housing Schemes for EWS and in narrow plots, the risers may be provided in one flight.

6.17.2.7 Handrails shall be provided with a minimum height of 90cm from the centre of the tread. In the case of public offices, assembly halls, hospitals, etc. an additional low rail shall be provided at a height of 75 cm.

6.17.2.8 The minimum headroom in a passage under the landing of a staircase and under the staircase shall be 2.2 m.

6.17.2.9 No room shall open directly to the flight of a stair.

6.17.2.10 External exit door of staircase enclosure at ground level shall open directly to the open spaces or shall be such as can be reached without passing through any door other than a door provided to/ from a draught lobby.

6.17.2.11 In the case of assembly, institutional, residential hotels, industrial and hazardous occupancies, the exit sign with arrow indicating the way to escape route shall be provided at a height of 1.5 m. from the floor level on the wall and shall be illuminated by electric light connected to corridor circuits or alternatively painted with fluorescent paint. All exit way marking signs should be flush with the wall and so designed that no mechanical damage shall occur to them due to moving of furniture and other heavy equipment. Further, all landings of floor shall have floor indication boards indicating the number of floor.

6.17.2.12 In the case of single staircase, it shall terminate at the ground floor level and the access to the basement shall be by a separate staircase. Whenever, a building is served by more than one staircase, one of the staircases may lead to basement level, provided the same is separated at ground level by either a ventilated lobby or a cut off screen wall without opening, having a fire resistance of not less than 2 hours with discharge points at two different ends or through enclosures. It shall also be cut off from the basement area at various basement levels by a protected and ventilated lobby/lobbies. The staircase shall be lighted and ventilated and the minimum size of openings on walls abutting open spaces shall be 0.3 sq.m. per landing.


6.18 LIFT:

6.18.1 At least one lift shall be provided in every building more than 16 m. in height.

6.18.2 Other requirements –

(a) The planning and design of lifts including their number, type and capacity depending on the occupancy of the building, the population on each floor based on the occupant load and the building height; shall be in accordance with Section 5 – Installation of Lifts and Escalators, National Building Code of India.

(b) At ground floor level, a grounding switch shall be provided to enable grounding the lift cars in an emergency.

(c) The lift machine room shall be separate and no other machinery shall be installed therein.

(d) The number of each floor shall be conspicuously painted in figures at least 15 cm. large on the wall opposite the lift / lifts opening or on other suitable surface so as to be distinctly visible from the lift cages.
(e) In high rise residential building; one of the lifts installed shall be freight lift.

6.18.3 Minimum one lift, preferably a stretcher lift should be provided in a hospital building exceeding three storeys.

6.19 PORCH / CANOPY:

A porch/canopy shall be at least 1.5 m. clear of the plot boundary. Area covered by porch upto a length of 5.50 m, parallel to the main entrance shall not be counted towards built up area. A parapet wall of maximum height of 0.25m. is permissible over a porch, and in case of a canopy it could be upto 1m.

6.20 GARAGE:

6.20.1 The garage shall be located in a plot as provided in Regulation 5.10.4.8 and shall not affect the access to the building.

6.20.2 The aggregate built up area of all the garages shall not exceed

(i) 10 % of the gross plot area, however, a minimum area of 20 sq.m. shall be permitted.

(ii) Area of a single garage shall not exceed 20 sq.m.


6.20.3 The maximum headroom in a garage and parking area shall be 2.4 m.

6.21 CABIN:

The size of cabins shall not be less than 3.0 sq.m. The minimum height of the cabin shall be 2.2 m.

6.22 CHIMNEY:

6.22.1 Chimneys shall conform to the requirements of IS 1645-1960.

6.22.2 They shall be built at least 0.9 m. above flat roofs, provided further that they shall project above the adjacent parapet wall. In the case of sloping roofs, the chimney top shall rise 0.6 m. above the ridge of the roof.

6.23 METER ROOM:

An independent and ventilated meter (service) room directly accessible from the outside shall be provided on ground floor and/or on upper floors, according to the requirements of the electric supply undertaking. The door to the room shall have fire resistance of not less than two hours.

6.24 RAMP:

In the case of parking spaces provided in the basement at least 2 ramps each of minimum 3-m. width and slope not more than 1:10 shall be provided, preferably at opposite ends. Such ramps may be permitted in marginal open spaces subject to clearance of 3.6 m.

6.25 LETTER BOX:

A letterbox of appropriate dimensions shall be provided on the ground floor residential and commercial buildings having G+2 and more storeys..

6.26 HANDRAIL:

Handrails shall be provided at a height of 90 cm. from the centre of the step of a staircase/ ramp surface. An additional rail shall also be provided at a height of 75 cm.


6.27 REFUGE AREA:

(a) In multi-storeyed and highrise buildings, at least one Refuge Area shall be provided on the floor immediately above 16 m.
(b) It shall be on the external walls as a cantilevered projection or in any manner.
(c) It shall have a minimum area of 15 sqm and a minimum width of 3.0 m.
(d) It shall not be counted in FSI.

6.28 SPECIAL AMENITIES FOR THE PHYSICALLY HANDICAPPED PERSONS:

Special facilities for physically handicapped persons as specified in Appendix XIX shall be provided in all buildings, either existing or proposed, to be used for public and/or semipublic offices, business/professional establishments, educational and medical purpose, recreational/amusement/community or cultural activities, stadiums or like uses or any public purpose where people gather for common activities.
(The regulation No. 6.28 above alongwith Appendix XIX thereunder have been replaced by new provisions and are excluded from sanction as EP-7)

6.29 STRUCTURAL DESIGN:

6.29.1. The structural design of foundations, elements made of masonry, timber, plain concrete, reinforced concrete, prestressed concrete and structural steel shall be carried out in accordance with Part VI Structural design, Section 1- loads, Section 2-Foundation, Concrete, Section 3 – Wood, Section 4 – Masonry, Section 5 – Concrete, Section 6 – Steel, of the National Building Code of India. The structural designer shall carry out various tests including soil test in case of high-rise buildings.

6.29.2. The structural design shall satisfy the requirement laid down for Seismic Zone-III. The structural designer shall have to certify accordingly.

6.30 QUALITY OF MATERIALS and WORKMANSHIP :

I. All material and workmanship shall be of good quality generally conforming to accepted standards of Public Works Department of Maharashtra and Indian Standard Specification and codes as included in Part V Building material and Part VII Construction practices and Safety of National Building Code of India.

II. All burrow pits dug in the course of construction and repair of buildings roads, embankments, etc. shall be deep and connected with each other in the formation of a drain directed towards the lowest level and properly stepped for discharge into a river stream, channel or drain and no person shall create any isolated burrow pit which is likely to cause accumulation of water leading to breeding of mosquitoes.

6.31 ALTERNATIVE MATERIALS, METHODS OF DESIGN AND CONSTRUCTION :

The provisions of these regulations are not intended to prevent the use of any material or method of design or construction not specifically prescribed by these regulations-provided such an alternative has been approved by a concerned authority.

The provisions of these regulations are also not intended to prevent their adoption for architectural planning and layout- conceived as an integrated development scheme.

The authority may approve any such alternative provided it is found that the proposed alternative is satisfactory and conforms to the provisions of the relevant parts regarding material, design and construction and that material and method of work offered is, for the purpose intended, at least equivalent to that prescribed in the regulations, in quality, strength, compatibility, effectiveness, fire and water resistance, durability and safety.

6.32 TESTS:

I. Whenever there is insufficient evidence of compliance with the provisions of these regulations or evidence that any material or method of design or construction does not conform to the requirements of these regulations or in order to substantiate claims for alternative material, design or methods of construction, the Competent Authority may require tests to be carried in advance as proof of compliance. These tests shall be made by an approved agency at the expense of the owner.

II. Test method shall be as specified by the regulation for the materials or design or construction in question. If there are no appropriate test methods specified in the regulations, the Competent Authority shall determine the test procedure. For methods of tests for building materials, reference shall be made to relevant Indian standards as given in the National Building Code of India.

III. The Competent Authority shall retain copies of the result of all such tests for a period of not less than two years after the acceptance of the alternative material.