iN E P A L    N A T I O N A L    B U I L D I N G    C O D E   NBC  206:  2015  

  

  

  

  

ARCHITECTURAL DESIGN REQUIREMENTS

Government of Nepal
Ministry of Urban Development

Department of Urban Development and Building Construction
Babar Mahal, Kathmandu, NEPAL

2072

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PrefaceThis module of Nepal National Building Code covers general building design requirementsin accordance with the principles stated in the Bhawan Ain–2055 (Building Act). The
principal focus is on the safety of occupants in a building during Earthquakes, Fires andNatural Disasters. Due to the limited technical manpower in the country’s constructionindustry, the code has been simplified for the ease of use and implementation. It is hoped thatwith the development of manpower and modernization of construction processes, it will bepossible to release a more sophisticated set of building planning guidelines in future.
Principal input to this code came from :Mr. Purna P. Kadariya, DG, DUDBC
Mr. Kishore Thapa, DDG, DUDBC
Mr. Mani Ratna Tuladhar, Sr. Div. Engineer, DUDBC
Mr. Arun Dev Pant, Architect, SONA
Dr. Sudarshan Raj Tiwari, Institute of Engineering, TU
Mr. Gyanendra Devkota, Architect, SONA
Mr. Rajesh Thapa, Architect, SCAEF
Mr. Bharat Sharma, Architect, Ex. DDG, DUDBC
Mr. Devendra Gangol, President, SONA
Mr. Bibhuti Man Singh, Architect, SCAEF
Mr. Amrit Man Tuladhar, Engineer, DUDBC

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Preface for revised NBC206:2015 will be written

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Contents	  1. TERMINOLOGY ............................................................................................................................................... 1  
1.1 General Terms .............................................................................................................................................. 1  
1.2 Classification of Building.............................................................................................................................. 1  1.2.1 Based on Occupancy.............................................................................................................................. 2  1.2.2 Based on Storey & Height...................................................................................................................... 3  2. MEANS OF EXIT .............................................................................................................................................. 4  2.1 Occupant Load ............................................................................................................................................. 4  2.2 General Exit requirement .............................................................................................................................. 4  2.2.1 Exit Doors ............................................................................................................................................. 5  2.3 Corridors and Passageways ........................................................................................................................... 6  2.4 Staircase & Ramps........................................................................................................................................ 6  2.4.1 General Staircase Requirements ............................................................................................................. 7  3. COMPONENTS OF THE BUILDINGS.............................................................................................................. 8  3.1 Plinth............................................................................................................................................................ 8  3.2 Minimum Room Dimensions ........................................................................................................................ 8  3.2.1 Height ................................................................................................................................................... 8  3.2.2 Size ....................................................................................................................................................... 8  3.3 Light &Ventilations ...................................................................................................................................... 8  3.4 Lifts.............................................................................................................................................................. 9  3.5 Basements .................................................................................................................................................. 10  3.6 Parking ....................................................................................................................................................... 11  4. SPECIFIC REQUIREMENTS FOR MULTI STOREY BUILDINGS ................................................................ 11  4.1 Medium Rise: ............................................................................................................................................. 11  4.2 High Rise ................................................................................................................................................... 11  5. ACCESSIBILITY FOR DISABLED................................................................................................................. 12  5.1.1 Requirements for Wheelchair bound people ......................................................................................... 12  5.1 Category 1: Minimally Accessible............................................................................................................... 12  5.2 Category 2: Partially Accessible .................................................................................................................. 13  5.3 Category 3: Fully Accessible....................................................................................................................... 14  6. SUMMARY OF REQUIREMENTS BASED ON OCCUPANCY ..................................................................... 14  6.1 Residences.................................................................................................................................................. 14  6.2 Assembly.................................................................................................................................................... 15  6.3 Educational................................................................................................................................................. 15  6.4 Hospitals and Clinic .................................................................................................................................... 16  6.5 Commercials & Office ................................................................................................................................ 17  6.6 Industries & Storage ................................................................................................................................... 17  A. REFERENCES ................................................................................................................................................ 17  B. GENERAL CHECKLIST FOR NBC-206......................................................................................................... 18  

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1.  TERMINOLOGY
1.1  General Terms
1.1.1Building:
Any Structure constructed of whatever material, whether used as human habitation or not and which includes
foundation, plinth, walls, floors, roofs & building services. Temporary structures like tents, tarpaulin shelter
etc. shall not be considered as buildings.
1.1.2 Public Buildings:
Public Buildings refer to all the government, non-government or private buildings which are used for providing
services, facilities, products and opportunities to the general public
1.1.3BuildingHeight:
The Height of the building shall mean the vertical distance from the average level of the ground around to theterrace of the upper most floor in case of a flat roofed building, to the center of the highest sloped part in case ofbuildings with the slope greater than 30oand to the eaves level of the highest sloped part in case of building withslope less than 30o. Building height may exclude any structure to hold the water tank, lift cover, parapet or any
decorative elements.
1.1.4Plinth:
Plinth means part of the building above the normal ground level and below the ground floor level.
1.1.5PlinthArea:
Plinth Area refers to area occupied by the ground floor of the building. Plinth area also includes the area occupied
by any structural elements of the building even if they are present outside the main building. The Plinth Area may
not include the atrium area or any voids greater than 1.5m x 1.5m. It however includes external areas which arecovered by cantilevers and are part of the circulation of building.
1.1.6Built-Up area
Built-up area shall be the sum of all the floor areas in the building used for one or more occupancy type. The
Built-Up area shall include all the area of the building that comes under FAR as per local byelaws.
1.1.7 Habitable Rooms
A room occupied or designed for occupancy by one or more people for the purpose of study, living, sleeping,eating, and cooking. This excludes spaces that are not used frequently or for long periods like toilet, bathroom,
laundry, store, pantry, corridor, cellar and attic.
1.1.8 Floor Height
Floor height refers to height of the room measured from the surface of the floor to the lowest point of the ceiling.
1.1.9 Basement
The lower story or story of a building that are either completely below the average ground level or extending up to
1.2m above the ground level.
1.1.10 Refuge Area
An area of refuge is a particular designated location in a building designed to hold occupants during a fire or otheremergency, when evacuation may not be safe or possible. Occupants can wait there until the arrival of the rescue
team. They are necessary in high rise buildings with building height greater than 25m which is beyond the reachof normal fire brigade.
1.2  Classification of Building

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1.2.1  Based on Occupancy
All buildings shall be classified according to the use or the character of occupancy into one of the following
groups. This classification may be used by other codes as requiredGroup A: Residential
Group B: AssemblyGroup C: Educational
Group D: Hospitals & Clinic
Group E: Commercial
Group F: OfficeGroup G: Industries
Group H: Storage
Group A: Residential
This shall include any building in which sleeping accommodation is provided for normal residential purpose
with or without cooking or dining or both facilities. Indigenous and vernacular residential buildings and NBC
type C buildings may be allowed to exempt from these rules.
Residential Buildings are further divided into
Sub Group A1: General residenceThis shall include any private residential building which has sleeping accommodation for not more than 40
persons. Based on occupancy load [Table 1], this relates to residential buildings having built up area lessthan500sq.m, beyond which any residential buildings shall be classified under A4
Sub Group A2: Residential with limited commercial use
This may include Residential buildings; with plinth area less than 150 sq.m and where part of the building
has been used for commercial or office purpose.
Sub Group A3: Residential Apartments
This shall include any building or structure which provides residential units in a single building for three ormore families, living independently of each other.
Sub Group A4: Dormitories and Hotels
These shall include any buildings under single management in which sleeping accommodation is provided
with or without dining facilities for more than 10 persons. Any residential building with occupancy load
greater than 40 persons is required to fulfill the requirement of this group. All the hotels shall fulfill theminimum requirements for this group.
Group B: Assembly
Assembly building shall include any building or part of building, which is designed for gathering of 50 ormore people. These shall include, theatres, cinema halls, auditorium, party palaces, exhibition halls, museums,
gymnasiums, covered hall, conference and meeting halls (above 50 capacity) and other buildings or spaces
within buildings where more than 50 persons are expected to assemble. Assembly buildings shall be subdivided into 2 groups
Sub Group B1: Assembly buildings and spaces with capacity up to 500 people
Sub Group B2: Assembly buildings and spaces with capacity above 500 people
Group C: Educational
Educational building shall include any buildings used as school, college, training institutes intended for morethan 25 students at a time. Educational buildings shall be divided into two categories
Sub Group C1: Primary Schools (up to standard 5)
Sub Group C2: Secondary Schools (beyond standard 5)
Any class room with more than 50 students should be treated as an assembly unit and shall be provided meansof exit as such
Group D: Hospitals and Clinics
Group D shall include all medical and health institutions which are intended to house persons suffering fromphysical or mental illness disease or infirmity, or to provide care for infants or aged persons. Smaller clinics
with area less than 100sq.m where the patients are not expected to stay may be excluded from this. However
all public health post should fulfill the Category 2 of disabled accessibility requirements as specified in Part 5

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Hospitals and Clinics shall be divided into two categories
Sub Group D1: Medical Institutions with less than 25 beds
Sub Group D2: Medical Institutions with more than 25 beds
Group E: Commercial
Group E shall include all the buildings or the part of the buildings designated for commercial use which
includes uses such as shops, markets, sale of merchandise either wholesale or retail, malls, Departmental store.
Residential normal rise buildings with plinth area less than 150sq.m where part of the building has been used
for commercial use may be categorized under subgroup-A2 as Residential with limited commercial use
Group F: Offices
These shall include any building or part of building which is used for official or business use.
Residential normal rise buildings with plinth area less than 150sq.m where part of the building has been used
as offices may be may be categorized under subgroup-A2 as Residential with limited commercial use
Group G: Industries
Group G shall include any building or part of the building or structure in which products or material of all
kinds and properties are fabricated, assembled, manufactured or processed. Certain type of industries may be
more hazardous than other hence require a different fire safety measures. The categorization of the Industries
based on fire load [which is the measure of the maximum heat that would be released if all combustibles in agiven fire area burn shall be dictated by Fire safety code 107.
Group H: Storage
These shall include any buildings used primarily for the storage of goods, ware or merchandise, cars or
animals and which are non- hazardous. Storage buildings in general have lower occupancy in proportion toarea for most of the time.
Some store may house more hazardous than other hence require a different fire safety measures. The
categorization of the storage buildings and areas based on fire load [which is the measure of the maximum heatthat would be released if all combustibles in a given fire area, burn] shall be dictated by Fire safety code 107.
1.2.2  Based on Storey & HeightGroup S1: General Buildings
Criteria - 1 to 5 Stories or below 16m
General buildings include those whose height are within reach of fire fighters ladders and hose streams. The
height of the building is comfortable to travel without the use of lifts. This is by far the most common type ofbuilt form overall.
Group S2: Medium Rise
Criteria - 6 to 8 Stories or between 16m to below 25m
Medium Rise includes buildings whose heights are within the reach of fire hose streams. In the case of an
emergency, rescue thorough stairways by firefighter are possible.
Group S3: High Rise
Criteria -9 to 39 Stories or 25m to below 100m
High rise includes buildings that are beyond the reach of normal firefighting provision on the ground. In caseof emergency the rescue operation shall require the use of fire lifts in the upper floors.
Group S4: Skyscrapers
Criteria -40 Stories and above or above 100m
Skyscrapers require a new approach in terms of safety, design and technology used and have not been
experimented in Nepal till date hence are not covered by this code. It is expected that they be covered byseparate guidelines after appropriate research.

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2.  MEANS OF EXIT
This part of the code defines the requirement for various components which forms the part of the exit system of
the building. Exits shall be defined as a continuous and unobstructed means of egress to a public way. The meansof exit includes the following
A. Doors and openings– Exit Medium
B. Passageways and corridors
Exit Route
C. Stairways and ramps
The requirements are guided primarily by ease of evacuation but shall also address minimum level of function andaccessibility.
2.1  Occupant Load
The requirement of exit system is based on no of occupants in the building or at each floor level or at each
occupancy zone within the building. The designer should calculate occupant load as if all of the area is occupied
to determine the maximum possible no of occupants to be accommodated by the exit system.
Table 1 - Maximum Floor Area Allowances per Occupant  Max. area per occupant
Building Type
[Sq.m] - A
A.
Residence
A1
General
11.5
A2
Residential with limited commercial use
9
A3
Residential Apartments
18
A4
Dormitory& Hotels
4.5
B.
Assembly
Fixed seating
As per no of fixed seats
Without fixed seat
1.4 netC.
Educational
1.8 netD.
Hospitals& Clinics
14
E.
Commercial
Main floors & Basement
2.75
Areas on other floors
5.5
F.
Office& Industries
9
G.
Storage/ warehouse
28

Minimum Occupants per
100sq.m [example]
9
12
6
23
72
56
8
37
19
12
4

The occupant load of the building or area within the building can be calculated using the relation below.
Net	
  or	
  gross	
  areaOccupant	
  Load	  of	
  the	
  building	  or	
  area =Area	
  per	
  occupant	  §   In any case the allocated area per occupant shall not be more than that specified under table 1-A.The building
can however be designed for higher occupant load by allocating lesser area per occupant.
§   Fractional occupant for each use shall be rounded up to the next whole number.
§   In case an area is used for dual purpose, the value which gives max occupant load shall be considered. In caseof multiple occupancy use within the single building, the individual occupant load shall be calculated andadded up.
§   The words ‘gross’ and ‘net’ areas are specific to certain occupancy type. Gross floor areas include all the area
including the rest rooms, internal corridors and any subsidiary rooms while net areas include just the areas
where the occupants reside.
§   For calculation of the width of main doorways and corridors at exit level and the width of the stairways, theeffective occupant load shall be sum of occupant load of consecutive 4 floors which has the highest no ofoccupant.
2.2  General Exit requirement
A.   The maximum travel distance to exits or stairways from any point within the single floor level shall not be
more than 30m for all types of building except when external corridor of 15m or more is part of the route, inwhich this distance may be increased to 40m. However it may be noted that external corridor are not allowed5

as medium of passage in case of High rise buildings unless they are fully enclosed by a glazed medium inwhich case it is considered as enclosed.
B.   All exits shall be free of obstructions.
C.   Exits shall be arranged in a way that they may be reached without passing through another enclosed
occupiedarea except in case of residential and apartment buildings
D.   All exit components shall be properly illuminated as far as possible. Illuminated exit signs shall be requiredfor occupancy Groups B1, D2, high rise buildings and category 3 disabled accessible buildings.
2.2.1  Exit Doors
A.   No exit door, inclusive of frame, shall be less than 1m in width and 2.1m in height except in case ofresidences where the minimum size of exit door shall be 0.9m in width by 2m height. The width of doors ofrooms which do not form a part of general human habitation or exit medium such as toilets and verandah ispermitted to width of 0.75m.
B.   In case of Assembly and Educational buildings minimum of two doors shall be provided if the no ofoccupants in the room is greater than 50.
C.   Exit doorway of Assembly buildings shall be openable without a key from the inner side
D.   The doors shall not obstruct the passages and staircase landings when open.
E.   Exits for disabled shall be as specified under Part 5
F.   The width of the doorways shall be measured in multiple of 500mm and calculated using table 2.
The width of the exit doorways and openings from the occupancy area at each level should be based on theoccupancy load at that level and can be calculated using table 3. However it should not be smaller than as
specified under heading 2.3
The width of main doorways leading to exterior shall be based on the combined occupant load of floor where it ispresent and 4 floors above it [or below it in case of basements or if terrace is considered as exit area].
Table 2 - Exit Width Calculation TableA
Minimum
Width (m)Residences
GeneralApartments/
Dormitories
Assembly
Educational
Primary Schools
Secondary Schools
Hospitals and Clinics
Commercial
OfficeStoresB
Occupant per unit
500mm width - A

CNo of occupants when exit
medium width exceeds the min.
limit - B

0.9
1.0

75
75

135
`150

1.2

90

216

1.0
1.2
1.2
1.0
1.0
1.0

75
75
75
75
75
75

150
180
180
150
150
150

Steps for calculation of width of Doorways§   Determine the occupant load of the building, floor or the section where the doorway is to be provided§   If occupant load is not known, it can be calculated using table 1§   If the no of occupants is less than what is specified in column C of table 2 then use the minimum
standard widthas given under column A§   If the no of occupants exceed the figure then use the formula below to calculate the width of the exit
medium𝑂𝑐𝑐𝑢𝑝𝑎𝑛𝑡	
  𝐿𝑜𝑎𝑑	  𝑋	
  0.5
𝑅𝑒𝑞𝑢𝑖𝑟𝑒𝑑	
  𝑤𝑖𝑑𝑡ℎ	
  𝑜𝑓	
  𝑡ℎ𝑒	
  𝑒𝑥𝑖𝑡	  𝑚𝑒𝑑𝑖𝑢𝑚	
   =𝑂𝑐𝑐𝑢𝑝𝑎𝑛𝑡	
  𝑝𝑒𝑟	
  𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑	
  𝑢𝑛𝑖𝑡	  	
  [𝐵]§   The calculated exit width can divided into two or more exits given that the widths or each are not lessthan what is specified under table 2 A6§   For disabled accessible buildings or sections of the buildings, ensure that the width of the exit comply
to the standards under section 5
2.3  Corridors and Passageways
Corridors and Passageways connect door ways to staircase and ramps.
A.   Width of corridors and passageways at each floor shall be based on the occupant load of that floor and canbe calculated using table 3 but it should not be smaller than what is specified in column A of Table 3.
B.   Width of main corridor and passage way to which the staircase opens shall be based on the occupant loadof consecutive 4 floor which has the highest occupancy
2.4  Staircase & Ramps§   Capacities of stair ways and ramps at any level shall be based on the occupant load of 4 floors directly
above it, while not being smaller than what is specified under column A of Table 3. It is assumed that
accumulation of loads in the exit route at any level is not affected by the load from 5thlevel or higher due
to Time factor.
The width of the exit route shall be calculated from the table below.
Table 3 Width of the Corridors, passageways, Staircase and ramps
A
B
C
Occupancy Type
Minimum
Occupant per 500mm
No of occupants when
Width (m) width [For ramps add 10 stairway width exceeds
occupants]
the min. limit
Residences
General
0.92545Residencewithlimited1
30
60commercial use
Apartments/ Dormitories
1.2
25
60
Assembly
Below 500 capacity
1.5
60
180
Above 500 capacity260240
Educational
Primary Schools
1.2
25
60
Secondary Schools
1.5
25
75
Hospitals& Clinics
1.8
25
75
Stretcher & equipment accessible
2.2
Commercial
1.25
50
125
Medium/High rise
1.5
50
150
Office1.25
50
125Medium/High rise
1.5
50
150
Stores1.25
50
125
Steps for calculation of width of Exit Route§   For building up to 5 storeys width of staircases and ramps shall be based on occupant load of all upper
floors. For buildings above 5 storeys capacities of exit route at exit level shall be based on maximum
occupant load from consecutive 4 floors of the building.
§   If occupant loads are not known, it can be calculated using table 1§   If the no of occupants is less than what is specified in column C of table 3 then use the minimum standard
width directly§   If the no of occupants exceeds the figure then use the formula below to calculate the width of the exit route
𝑅𝑒𝑞𝑢𝑖𝑟𝑒𝑑	
  𝑤𝑖𝑑𝑡ℎ	
  𝑜𝑓	
  𝑡ℎ𝑒	
  𝐶𝑜𝑟𝑟𝑖𝑑𝑜𝑟𝑠, 𝑝𝑎𝑠𝑠𝑎𝑔𝑒𝑤𝑎𝑦𝑠, 𝑠𝑡𝑎𝑖𝑟𝑐𝑎𝑠𝑒	  &	
  𝑅𝑎𝑚𝑝𝑠	
  𝑂𝑐𝑐𝑢𝑝𝑎𝑛𝑡	
  𝐿𝑜𝑎𝑑 ∗ 0.5=
𝑂𝑐𝑐𝑢𝑝𝑎𝑛𝑡	
  𝑝𝑒𝑟	
  𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑	
  𝑢𝑛𝑖𝑡	  [𝐵]7§   The calculated exit route width can distributed into two exits given that the widths are not less thanwhat is specified under table 3 A
For reduced use staircases which are not part of the normal exit system such as accesses to lofts, attics andterraces, the minimum width shall be 600mm.
Fig. 1 Width of the exit route or the staircase at any point is calculated based on the occupant load of the upper
four floor

2.4.1  General Staircase Requirements§   For all buildings above 500sq.m in plinth area there shall be at least two staircases. Additional exit route
shall be provided for every 500sq.m of plinth area there on.
§   Specific Stairways requirement for medium rise and high-rise buildings are provided under respective
headings§   Any High rise building above 50m shall have one pressurized staircase as dictated by the ‘Fire safety
code’.
§   All secondary or fire escape staircase shall have at least one side facing towards exterior
All staircases except those that are meant for reduced use and not the part of exit system staircases such asaccesses to lofts, attics and terraces shall conform to following requirements.
Table 4 Staircase Details
Minimum Tread – A
Residences
Other Buildings
Maximum Riser– B
Residences
Other Buildings
Maximum no of risers per flight
Minimum Head room under the staircase - C
Height of the Handrail from center of the tread - D

250mm [10”]279mm [11”]190mm [7.4”]
175mm [6.9”]
152m [6’-6”]
900mm [3’]8

Fig. 2 General Staircase requirements

3.  COMPONENTS OF THE BUILDINGS
3.1  Plinth
Minimum plinth height shall be 450mm from the existing road level for all buildings. The road level can bedifficult entity to define as road and site may be in gradient. However, it should be understood that, the main
goal of this rule is to ensure that the entry to the building remains above the road level as there is a tendencyof road level increasing when they are maintained overtime.
Parking and Garage may have no plinth.
3.2  Minimum Room Dimensions
3.2.1  Height
For Residential building
The height of all rooms for human habitation shall not be less than 2.4m measured from the surface of thefloor to the lowest point of the ceiling [bottom of slab]
In the case of pitched roof, the average height of rooms shall not be less than 2.4m.
The minimum clear head room under a beam or any such structure including after installation of false ceilingshall be 2.1m.
The height of the bathroom or water closet shall not be less than 2m
For Office and Commercial building the minimum floor height shall be 2.9m
Floor heights for Assembly, Hospitals, Educational and Industrial buildings shall not be less than 3.2m for
Hill &Mountain region and 3.6m for Terai region.
3.2.2  Size
The minimum size of the room shall not be less than the following
Min Dimension
A. Minimum habitable room Size
2.0m
B. Kitchen
1.8m
C. Toilet cubicle / water closet
0.9 mBath Room
1.2m
Combined water closet with bath room
1.2 m

Minimum Area
6 sq.m
5 sq.m
1.2 sq.m
1.8 sq.
2.8 sq.m3.3  Light &Ventilations
All habitable rooms shall have the provision to admit natural light and ventilation.
Minimum area of openings (excluding internal doors) for a habitable room towards exterior or into an open
verandah shall be as follows.

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General Openings Requirements
A. Min. area of openings for natural light

B.

C.

KitchenRecommended
1/10th of the room area for hilly
regions
1/8thof the room area for otherregions
25% more
1/8th of the roomthanarea for hilly regions
minimum
1/6th of the room
permitted
area normallyth
1/16 of the room area

Reference Opening
size required for
4mX4m room
1.0 X 1.5
1.32 X 1.5
1.32 X 1.5
1.75 X 1.5

Min. area of General
0.6 X 1.5
openingfor requirement
natural ventilation
Hospitals: Patient 1/8th of the room area
1.32 X 1.5
rooms & Schools
No portion of the room shall be considered naturally lighted if it is more than 7.5mm from the opening
assumed for lighting that portion.
Minimum size of internal courtyard from which admission of light is permitted for a habitable room shall be
3m X 3m for normal rise building. For buildings higher than 5 stories the size of courtyard shall increase by
0.5m or equivalent area for every additional floor or 4m [whichever is less]These requirements may be relaxed for building occupancy type other than Residence, Hospitals andAcademic if the artificial lighting and ventilations are installed to satisfy the needs.
3.4  Lifts
Lifts indicates appliance designed to transport persons or material in a vertical direction.
A.   Lift Provision requirement§  Provision of Lift(s) shall be made for all the buildings above 5 stories or 16m in height.
§  Provision of at least two lifts shall be made for high rise building [above 8 stories or 25m in height]. At
least one of the lift shall be fire lift that can be used by fire fighter for rescue and access in case of
emergency.
§  If lifts are provided, at least one of the lifts within the buildings under category 2 and 3 of ‘Disabled
Accessibility’ shall be accessible to the people on the wheel chairs. It may be noted however thatprovision of lifts for buildings under category 2 is not mandatory while in case of category 3, ramps may
substitute for lifts.
B.   Lift Size and Capacity requirement§  Minimum width of the Category 3 disabled accessible lift car shall be 1200mm X 1400mm while it shallhave minimum clear opening of 800mm§  Minimum width of Hospital lift car shall be 1200mm X 2400mmwhile having a minimum clear openingof 900mm§  A fireman’s lift shall have loading capacity of not less than 500kg [8 persons]. The lift car of the fire lift
shall have floor area not less than 1.44sq.m.
C.   Disabled Accessibility Requirements§  All lifts shall be accessible without disturbance from the parking and main approach of the building to thewheel chair bound people§  All disabled accessible lifts within the buildings shall emit audible sound to ease the travel of visually
impaired people.
§  Height of the controls from the lift floor level shall be at most 1200mm for all disabled accessible lifts.
D.   Fire Safety Requirements§  Shafts for all lifts shall be enclosed by walls having fire resistance of two hours

10§  The fire lift shall have fire protection and control mechanism as specified under ‘Fire safety code – 107’E.   Electrical Installation Requirement§  The electric supply for the fire lifts and Hospital lifts shall be on a separate supply line from the supply
mains. In case of failure of normal electric supply, it shall automatically trip over to an alternate powersource§  All lifts in case of power failure shall stall with the door open at the nearest floor to enable the passenger
to exit.
Fig. 3 Lift car sizes

Min. dimensions of disabled accessible Lift
A
1250 mm
B
1400mmC
800mm

Min. dimension of Hospital liftsA
1200 mmB
2400mmC
900mm

3.5  Basements
Basements are the lower story or storey of a building that are either completely below the average groundlevel or extending up to 1.2m above the average ground level. Any floor above 1.2m level shall be considered
as Semi-basement floor.
A.   Basic Requirements§   Basement floor shall not be used for residential purpose§   The minimum height of the basement floor shall be 2.4m
§   Adequate arrangement shall be made such that surface drainage doesn’t enter the basement. The walls andfloors of the basement shall be water tight.
B.   Ventilation Requirements§   Each basement shall be separately ventilated. Vents with cross sectional areas not less 2.5% of the floorarea spread preferably around the perimeter of the basement shall be provided through stall boards,
pavement light or through shafts [in case of double basements]§   Each basement above 200sq.m shall have minimum of one each system of air inlets and smoke outlet
served through mechanical system. Additional vent system shall be provided for every 200sq.m of plinth
area there on.
C.   Safety Requirements§   The staircase of the basement shall have fire resistance value of not less than 2hours.

11§   As specified under section 2.2 maximum travel distances to the stairway or exit shall not be more than
30m beyond which another means of exit shall be provided. Ramps can be considered as one of the meansof access.
3.6  Parking
These basic parking requirements shall be applicable to areas where vehicular transport is available and isassociated with off street parking§   The minimum height clearance for indoor parking space shall not be less than 2.2m.
§   For common parking, area allocated for each car shall not be less than 2.5m X 4.5m.

Minimum area for common parking
A
2500 mm
B
4500 mm§   Parking area allocated for each bike and scooter shall not be less than 1.25 sq.m while the same for thecycle shall not be less than 1 sq.m§   The gradient of ramp leading to parking space for occupancy type other than A1 and A2 shall not be morethan 1:5.
4.  SPECIFIC REQUIREMENTS FOR MULTI STOREY BUILDINGS
Under Part 1.2.2 The Multi storey buildings have been categorized into 4 groups. Besides all the above
mentioned requirements the Medium rise and High Rise building need to follow additional requirement as
specified below
4.1  Medium Rise:
These includes buildings between 6 to 8 Storey or between 16m to 25m
A. Lift
All midrise buildings shall be provided with lift.
B. Staircase
In all midrise buildings, the main staircase shall be of enclosed type separated for theoccupancy area by fire/smoke check door as dictated by fire code 107
All midrise buildings shall have provision of emergency or secondary staircase
which shall has at least one side open to exterior
Spiral staircase shall not be permitted as means of exit
C. Parapet
Minimum height of Parapet shall be 1m excluding finishing
4.2  High Rise
These includes buildings between 9 to 39 storey or 25m to 100m
A. Lift
In all high rise buildings minimum of two lifts shall be provided. At least one of thelift shall be fire lift that can be used by fire fighter for rescue and access in case of
emergency. The requirement of fire lifts have been briefly covered under Section3.4
B. Staircase
All High Rise buildings shall have the provision of secondary or emergency staircase

12

regardless of occupancy type which shall have at least one side open to exterior
All High Rise buildings above 50m shall have at least one staircase which should bepressurized and fire proof as dictated by fire safety code 107.
External staircases for high-rise buildings are not recommended because of vertigo
effect on people. The external staircases shall not be used on the buildings above
50m
C. Restrictions Buildings under Subgroup A1 & A2 [Individual Residences and residences withlimited commercial use] are not allowed
School buildings & Medical institutions under sub group D2 shall not be allowed
D. Refuge Area Refuge area of at least 10m2 or area equivalent to 0.2m2 per occupant shall be
provided on the 10th storey or the storey at 25m level whichever comes first. The
same shall be provided after every 4 stories or 15m interval whichever comes first.
The no of occupant shall be calculated considering the occupant load of 2 storeys
above and below the refuse area.
As far as possible the refuge area shall be in central area adjoining the main fire lift
or fire staircase and shall have at least one wall as external face of the building. The
refuge area shall be as specified under ‘Fire Safety Code-106’
E. Parapet
Minimum parapet height of shall be of 1.2m excluding finishing
5.  ACCESSIBILITY FOR DISABLED
The main goal of this section is to make all or part of the public buildings and facilities used by the publicaccessible to and functional for the physically challenged people of the society.
The major portion of accessibility for disabled covers wheel chair bound people. It is assumed that by making
the buildings accessible for such people, they are automatically accessible to the other differently able people
5.1.1  Requirements for Wheelchair bound people
The average size of the Standard manual wheel chairis 640mm-700mm X 900-1100mm. To measuredoor clearance, we add 50mm to each side to leaveroom for hands. Which means doorways designed foruse by disabled people shall have at least 800 mm
clear opening while the recommended size is 900
mm.Any reference to disabled accessible doorways
and entrance under category 1, 2 and 3 shall meetthis requirement.
In general to rotate 1 wheel chair full 180º minimum
space required is 1800mm in diameter. This is thestandard space required for fully wheel chair
accessible public facilities including Public toilets,
hospitals, ATM counters
Accessibility requirements for the disabled have beenaddressed by categorizing the buildings into three
categories each of which are required to fulfill set ofprovisions.

Fig. 4 Standard wheelchair and doorway sizeA
640-700mm
B
900-1100mm
C
800mm

5.1  Category 1: Minimally Accessible§   All government & semi-government public buildings and dormitories with plinth area below 100sq.m.

Required
Provisions§   At least one entrance of category 1 public building shall be accessible to thewheelchair bound people and he should be able to access the reception area and any
public service or facilities provided by the building. The person shall also be able toaccess at least one of the toilets. As such, any public service units, the reception area

13

A.

Ramps

B.

Sanitary
Facilities

and at least one of the toilets shall be located on the Ground floor or the floor thataccessible from approach.
§   Minimum gradient of1:8 [7 degrees]for the difference in height not more than
450mm§   Minimum gradient of 1:12 [5 degrees]for the difference in height more than 450mm§   Shall have level platforms for every1.5m of vertical rise. The level platform shall not
be less than 1.2m in length and the same width as the ramp.
§   Minimum width of ramp shall be 1m§   Shall have at least 1 toilet with Commode§   Shall have door with minimum clear opening of 800mm

5.2  Category 2: Partially Accessible§   All government and semi-government buildings with plinth area between 100sq.m& 500sq.m§   All forms of Health posts and Hospitals under sub group D1 [less than 25 beds]§   Commercial &Office buildings with plinth area between250sq.m & 500sq.m§   All secondary level school (more than class 5)§   To all assembly buildings with occupancy higher than 500 person
Required§  At least one primary entrance to a building shall be usable by the physically
Provisions
disabled and the disabled person should be able to access the reception area, groundfloor and the toilet.Although provision of lift is not compulsory for category 2
buildings, if provided, it should be accessible to person on wheel chair. As such, inabsence of lift all the public oriented services, reception area and at least one
disabled accessible toilet shall be provided on the ground floor or the floor that isaccessible from approach.
§  Assembly area above 500 person capacity [either as an individual building or as apart of other building] shall be accessible to the wheel chair bound people.
A. Ramps§  Minimum gradient of 1:8 [7 degrees]for the difference in height not more than
450mm
§  Minimum gradient of 1:12 [5 degrees]for the difference in height more than450mm
§  Should have level platforms for 1.5m of vertical rise. The level platform shall not
be less than 1.2m in length and the same width as the ramp.
§  Level platforms should be provided at tops and changes of directions§  Minimum width of ramp shall be 1m§  Handrails shall be provided if total rise exceeds 1m and should be positioned
between 850mm and 1m above the surface of such ramp.
§  Should have non-slippery surface
B. Openings§  Shall have flush threshold or at maximum threshold limit shall not exceed 12mm
§  Minimum clear width in openings: 800mm§  Minimum clear width in main openings 900mm§  The control or handle to the door at major doors should be placed between 9001200mm from the floor
C. Sanitary§  Should have at least 1 water closet for the wheel chaired bound person that is at
Facilities
minimum§   900mm wide§   1600mm deep§   Shall have Commode§   Shall have door with minimum clear opening of 800mm
The water closet can be unisex
D. Cinema Hall/ §  Every halls above capacity of 500 should be able to accommodate min of 3 wheel
Auditoriums
chaired person for every 500 people
E. Lifts§  The minimum required size of disabled accessible lift are provided under part 2.2.4§  All lifts shall have audible sound to enable easy movement for the visually
impaired.
§  Height of the controls from the floor level of the lift car shall be at most 1066mm

145.3  Category 3: Fully Accessible§   All Hospital under Sub-Group D2 [more than 25 beds]
Fig. 5 International sign for§   All public building with plinth above 500sq.m
disabled accessibility. Such signs§   Commercial & Office buildings with plinth area above 500sq.m
Besides the requirement under part 4.1.2, all habitable part of the shall be used in important area ofbuilding should be fully accessible to the disabled either through lifts or fully accessible buildings underramps. The lifts shall meet the minimum standard for disabled category 3
accessibility as described under heading 3.4
Other requirement includes§   For every 20 toilet compartments, there should be 1 full disabled
accessible toilet. It is to be noted that the disabled accessible toilet
can be unisex. All the Sanitary fixtures shall be as guided by NBC
Code.
§   Symbol indicating disabled accessibility [fig 11] shall be in place atlift, toilets, main exits, parking areas. This symbol should be incontrasting colour and properly illuminated so that it can be easily identified visually impaired people.
§   Lift should fulfill the minimum requirements for disabled accessibility as specified under heading 3.4 C
6.  SUMMARY OF REQUIREMENTS BASED ON OCCUPANCYThis section intended as a quick reference for individual building category and in most cases refers to previous
sections. It may however contain requirements which have not been specified in previous section.
6.1  Residences
S. No.
1.

2.

3.

Elements ofbuilding
Occupancyload

Particulardimensional aspects
Maximum area per
Occupant

Exit

Maximum distance
to exits or stairways
within single floor
Minimum size of the
Doorway
Width of thecorridors
Staircase width
Staircase Designs
PlinthMinimum Room
Dimensions
Light &Ventilations
Lifts
Basements

Componentsof BuildingStandard

Reference

General Residence
11.5 sq.m
Residence with limited com. Use
9 sq.mApartments
18 sq.m
Dormitories
6 sq.m
30m
40m for external corridor

2.1

0.9m X 2m or as per Table 2

2.2.1

As per Table 3

2.3

As per Table 3
Shall confirm with 2.4.1
Min. 450mm from existing road level
Refer 3.2

2.4

Refer 3.3
As per midrise & high rise requirements
Refer 3.5

2.2

3.1

3.4 & 4.

15

6.2  Assembly
S. No.
1.
2.

3.

5.

Elements ofbuilding
Occupancyload
EgressComponentsof Building

Accessibility
for Disabled

Particulardimensional aspects
Maximum area per
Occupant
Maximum distance toexits or stairways
within single floor
Doorway
Width of the Corridors
Staircase & Ramp
width
Staircase Designs
Minimum Floor
HeightParking Requirements
Provisions for disabled
Mandatory forcapacity above 500

Standard

Reference

1.4 sq.m net

2.1

30m
40m for external corridor

2.2

As per Table 2
As per Table 3
As per Table 3

2.2.1
2.3
2.4

Shall confirm with 2.4.1
3.2m at any point for Hills & Mountains
3.6m for Terai region
Min. 1 car park for every 25 persons
Min. 1 bike park for every 10 persons
Provision for 3 wheel chaired person forevery 500 people
Shall fulfill the requirement of category 2

3.6
Refer
local
byelaws
5.

6.3  Educational
S. No.
1.
2.

Elements ofbuilding
Occupancyload
EgressParticular dimensional aspects

2.1

Maximum distance to exits orstairways within single floor
Width of the Doorway

30m
40m for external corridor
As per Table 2
No door shutter shall exceed 1.2m
in width
As per Table 3
As per Table 3

2.2

PlinthMinimum Height of the room

4.

Specificrequirement

Reference

1.8 sq.m net

Staircase Designs
Componentsof Building

OthersMaximum area per Occupant

Width of the Corridors
Staircase width3.

Primary
Schools

Light &Ventilations
Minimum
For individualarea perseats
student
For bench seats
Maximum Distance between
black board and Last row ofbenches
Minimum Distance between
black board and the first row
Sanitary Units

2.2.1
2.3
2.4

Shall confirm with 2.4.1
Min. 450mm from existing roadlevel
2.75 m
3.2m for Hills &mountains
3.6m for Terai
Refer 3.3None
1.2 sq.m
1 sq.m7m

1 sq.mnone

2m

NBC 208 Table B10

3.1
3.2.1

16

5.

Accessibility For schools with students
for Disabled

none

Shall fulfill therequirement of
category 2

5.2

Recommended areas and lighting requirements for various units
S. No.
1.

Unit
Library

Minimum Standard
Lighting [lux]Mandatory for every school with 500 or more100
students
Minimum Capacity
10% of total students
Area per student
2.4 sq.m per student
2.
Science Lab
4 sq.m per student
200
Other Laboratory 2.4 sq.m per student
Art Room
2.7 sq.m per student
100
3.
Teacher’s Room 1.8 sq.m per student
4.
Boarding
Dormitories
2.8 sq.m per bed in
Accommodation
double bunk
Dining Hall
1 sq.m per student
70
Kitchen & Annexes.36 sq.m per student
80
Urinals / Toilets
1 per 15 students
Wash Basin
1 per 20 students
Showers
1 per 20 students
Referenced from “Guideline or Architecture Design & Approval of School/College”

Remark6.4  Hospitals and Clinic
S. No.
1.
2.

Elements ofbuilding
Occupancyload
EgressParticulardimensional aspects
Maximum area per
Occupant[Sq.m]
Maximum distance toexits or stairways
within single floor
Doorway

Width of the Corridors
Staircase width
Staircase Designs
3.

Componentsof Building

PlinthMinimum Height of
the room
Light &Ventilations
Lifts

4.

Accessibility
for Disabled

Less than 25 beds

More than 25 beds

Reference

14 sq.m

14 sq.m

2.1

30m
40m for external corridor

2.2

Width as per Table 2
Doors of Operation suite and Delivery suite
shall be two leaf type with min. width of
1.5 and shall have self-closing devices
As per Table 3
As per Table 3
Shall confirm with 2.4.1

2.2.1

Min. 450mm from existing road level
3.2m for Hills & mountains
3.6m for Terai
Min area of opening for natural ventilation
shall be1/6th of the room area
Other requirements shall confirm with 3.3
Min size of patient lift car: 1.2m X 2.4m
Shall fulfill the
Shall fulfill therequirement of
requirement of
category 2
category 3

3.1
3.2.1

2.3
2.4

3.3
3.4
5.

17

6.5  Commercials & Office
S. No. Elements ofParticular dimensional aspects
building
1.
Occupancy load Maximum floor area per
Main floor &Occupant[Sq.m]
Basement
Other floors
2.
EgressMaximum distance to exits or stairways
within single floor
Width of the Doorway
Width of the Corridors
Staircase width
Staircase Designs
3.
Components of Minimum Height of the room
Building
Light &Ventilations
Basement
Parking Requirement
4.
Accessibility for
DisabledCommercials

Offices

Reference

2.75 sq.m

9 sq.m

2.1

5.5 sq.m
30m
40m for external corridor
As per Table 2
As per Table 3
As per Table 3
Shall confirm with 2.4.1
2.9m
Refer 2.2.3
Refer 3.5
Refer 3.6
Refer 5.0

2.2
2.2.1
2.3
2.4
3.2.1

6.6  Industries & Storage
S. No. Elements ofParticular dimensionalbuilding
aspects1.
Occupancy load Maximum floor area per
Occupant[Sq.m]
2.
EgressMaximum distance to exits orstairways within single floor
Width of the Doorway
Width of the Corridors
Staircase width
Staircase Designs
3.

4.

Components of Minimum Height of the room
Building
Light &Ventilations
Basement
Accessibility for
Disabled

Industries

Storage

Reference

9 sq.m28 sq.m

2.1

30m
40m for external corridor
As per Table 2
No door shutter shall exceed 1.2m inwidth
As per Table 3
As per Table 3

2.2
2.2.1
2.3
2.4

Shall confirm with 2.4.1
3.2m for Hills & mountains
3.6m for Terai
Refer 2.2.3
Refer 3.5
None

A. REFERENCES§   National Building Code of India - 2005
§   International Building Code - 2009§   Building Codes Illustrated, Francis D.KChing/Steven R Winkel§   Bye laws for municipalities & urbanizing VDCs within Ktm Valley-2064§   Neuferd Architect’s Data, Third Edition

3.2.1

B. GENERAL CHECKLIST FOR NBC-206
1.
2.

3
3.1
3.2
3.3

3.4
3.5
3.6
4.
5.

BUILDING ELEMENT
CLASSIFICATION OF BUILDING
Building Purpose
Sub Group
MEANS OF EXIT
Effective Occupant Load for exit calculation
Max. travel distance to exit point in each floor (m)Min. width of exit door including frame (mm)Min. height of the exit door including floor (mm)No of staircase and Ramps
Total Width of the Stair case / Ramps (mm)Tread of Stair case (in mm)
Riser of Stair case (in mm)
Max. no of riser on one single flight (Nos)
Height of the Hand Rail (in mm)
COMPONENT OF BUILDING
Average Plinth height (mm)Room Height (m)Light & Ventilation
Min ratio of opening area for natural light (O) to area of habitableroom (A) – (O/A)
Min ratio of opening area for natural ventilation (O) to area of
habitable room(A) – (O/A)
Lifts
Presence of fire lift
Size of Lift car (m)Basements
Percentage of vent in basement
Parking
Parking area allocated for each car (L X B) (mm)Gradient of ramp for vehicle use
BUILDING CATEGORY BASED ON HEIGHT
Height of parapet wall or balcony handrail (m)Provision of fire escape and fire safety
DISABLED ACCESSIBILITY CATEGORY
No of floors accessible to wheel chair bound people
Max. gradient of ramp
Min. width of ramp (m)As per submitted Design

Yes

No

Yes
No
None / 1 / 2 / 3

Remarks