National Building Code of India

What to remember

• The National Building Code of India (NBC) is published by the Bureau of Indian Standards (BIS). It is a model code for building design, construction, fire safety, services and maintenance.
• The current edition is NBC 2016, in two volumes and 13 parts (Part 0 to Part 12). Earlier editions came in 1970, 1983 and 2005.
• NBC is recommendatory. It becomes binding when a state or local body adopts it in its own building rules.

1. Nature and history of the Code

The NBC gives a single set of technical rules so that buildings are safe, healthy and well planned. It was first published in 1970 and revised in 1983, 2005 and 2016. It is prepared by a BIS committee of architects, engineers, planners and government departments. It sets minimum standards. Local bodies add their own rules in building bye-laws or building rules, for example the Andhra Pradesh Building Rules, and these follow the Code in many matters. The Code refers to many Indian Standards (IS codes) for detailed design.

2. Parts of NBC 2016

Volume 1 contains Parts 0 to 6 and Volume 2 contains Parts 7 to 12. Part 3 is the one most used by planning staff for plot, setback and room rules. Part 4 is for fire safety.

3. Classification of buildings by occupancy

Buildings are also grouped by height. High-rise buildings are those of 15 m height or more (the usual NBC meaning), and they need stricter fire and lift norms.

4. General building requirements (Part 3)

Typical minimum values are given here. Treat them as standard design values; the local rules may differ.

Other points: every habitable room needs windows or openings for light and cross ventilation; the building must keep the required setbacks; buildings must be accessible for persons with disabilities (ramps, wide doors, accessible toilets); stairs need handrails and a rise and tread that are comfortable (for houses about 190 mm rise and 250 mm tread).

5. Fire and life safety (Part 4)

Fire safety means preventing a fire, limiting its spread and letting people escape.

• Types of construction (Type 1 to Type 4) are based on how long the structure resists fire.
• Means of egress: exits, staircases, corridors, refuge areas; exit routes must be clear and marked.
• Travel distance to an exit is limited by occupancy.
• Fire fighting systems: hydrants, wet riser, down-comer, sprinklers, smoke detectors, alarms, fire pumps and water tanks.
• Fire lift and staircase: required in high-rise buildings; the fire staircase should be enclosed.
• Open space around buildings for fire tenders to reach.

6. Structural design and materials (Parts 5 and 6)

Part 6 covers loads, foundations and structures in concrete, steel, masonry and timber. Key Indian Standards:

Types of loads. Dead load (weight of the structure), imposed or live load (people, furniture), wind load, earthquake load, snow load (cold regions). Unit weight of reinforced concrete is taken as 25 kN per cubic metre. A typical imposed load for residential rooms is 2 kN per sq m.

Concrete grade. M20 means a concrete with 20 N per sq mm characteristic compressive strength at 28 days (150 mm cube). M20 is the common minimum for reinforced concrete. Nominal mixes: M15 = 1:2:4, M20 = 1:1.5:3, M25 = 1:1:2 (cement : sand : coarse aggregate).

Worked example 1. A slab 5 m x 4 m and 150 mm thick. Self weight per sq m = 0.15 x 25 = 3.75 kN per sq m. Total dead load = 3.75 x 20 = 75 kN.

Worked example 2. The same slab carries an imposed load of 2 kN per sq m. Total imposed load = 2 x 20 = 40 kN.

Worked example 3. Cement for M20 (1:1.5:3) in terms of parts: total parts = 1 + 1.5 + 3 = 5.5. Cement share = 1/5.5 of dry volume.

Seismic zones of India are marked from the lowest to the highest risk in IS 1893, and structures in higher zones need stricter detailing. Building materials in Part 5 include bricks, cement, stone, timber, steel, glass and new materials, which should meet the relevant IS specification.

7. Services and other parts

• Part 8: electrical wiring, lighting, ventilation, air conditioning, lifts, escalators, acoustics.
• Part 9: water supply, drainage, sanitation, solid waste, rainwater and gas piping.
• Part 7: safety at construction sites, scaffolding, excavation, demolition and protective gear.
• Part 10: tree planting, parks, signs and hoardings.
• Part 11: sustainability, energy and water saving, green buildings.
• Part 12: operation, repair and maintenance of buildings.

8. Permits and responsibilities (Part 2)

No building is to be built, changed or demolished without a building permit from the local authority. The owner applies with drawings signed by a registered architect or engineer. The authority checks the plan against the rules, may inspect at key stages (such as plinth level) and gives an occupancy certificate when the work is complete and safe. Owners must use sound materials and follow the sanctioned plan. Professionals are responsible for correct design and supervision. Ward-level staff help the municipality by field checks of work in progress.

Exam traps

• NBC is published by BIS, not by a ministry or municipality.
• NBC is a model code; it binds only when adopted in local rules.
• Part 3 is for development control; Part 4 is for fire; Part 6 is for structures.
• Group C is Institutional and Group D is Assembly; do not swap them.
• High-rise means 15 m or more; it is a height limit, not a count of floors.
• Fire fighting for electrical fires uses CO2 or dry powder, not water.
• IS 456 is concrete; IS 800 is steel; IS 1893 is earthquake.
• A habitable room is not the same as a kitchen, bathroom or WC.

One-liners

• 1. NBC is published by the Bureau of Indian Standards.
• 2. NBC was first published in 1970.
• 3. NBC 2016 has 13 parts, numbered 0 to 12.
• 4. Part 4 deals with fire and life safety.
• 5. Part 6 deals with structural design.
• 6. Part 9 deals with plumbing services.
• 7. Group A is residential occupancy.
• 8. High-rise buildings are 15 m or more in height.
• 9. A habitable room needs at least 9.5 sq m of area.
• 10. Minimum height of a habitable room is 2.75 m.
• 11. IS 1893 gives earthquake-resistant design criteria.
• 12. Ramps for the disabled should not be steeper than 1 in 12.

Practice questions

1. The National Building Code of India is published by the

   1. Central Public Works Department
   2. Town and Country Planning Organisation
   3. Indian Roads Congress
   4. Bureau of Indian Standards
   Answer

   D. Bureau of Indian Standards

   NBC is a BIS publication.

2. The National Building Code was first published in

   1. 2016
   2. 1970
   3. 1947
   4. 1991
   Answer

   B. 1970

   First edition 1970; revised 1983, 2005 and 2016.

3. The latest edition of the NBC referred to here was issued in

   1. 1983
   2. 2022
   3. 2016
   4. 2005
   Answer

   C. 2016

   NBC 2016 is the edition with 13 parts.

4. NBC 2016 is divided into how many parts (numbered from 0)?

   1. 20
   2. 10
   3. 9
   4. 13
   Answer

   D. 13

   Parts 0 to 12 make 13 parts.

5. In NBC 2016, fire and life safety is dealt with in

   1. Part 1
   2. Part 4
   3. Part 8
   4. Part 11
   Answer

   B. Part 4

   Part 4 is Fire and Life Safety.

6. In NBC 2016, structural design is dealt with in

   1. Part 2
   2. Part 5
   3. Part 6
   4. Part 9
   Answer

   C. Part 6

   Part 6 is Structural Design.

7. Development control rules and general building requirements are in

   1. Part 12
   2. Part 10
   3. Part 7
   4. Part 3
   Answer

   D. Part 3

   Part 3 covers rules like setbacks and room sizes.

8. Plumbing services are covered in NBC Part

   1. 3
   2. 9
   3. 6
   4. 11
   Answer

   B. 9

   Part 9 is Plumbing Services.

9. The approach to sustainability is in NBC Part

   1. 4
   2. 11
   3. 8
   4. 2
   Answer

   B. 11

   Part 11 covers sustainability.

10. Administrative provisions such as permits and duties of owners are in NBC Part

    1. 1
    2. 5
    3. 2
    4. 12
    Answer

    C. 2

    Part 2 is Administrative Provisions.

11. Under NBC occupancy classification, Group A is

    1. Residential
    2. Assembly
    3. Business
    4. Storage
    Answer

    A. Residential

    A = Residential.

12. Under NBC, a cinema hall belongs to

    1. Group G (Industrial)
    2. Group F (Mercantile)
    3. Group B (Educational)
    4. Group D (Assembly)
    Answer

    D. Group D (Assembly)

    Cinemas are assembly buildings.

13. Under NBC, a hospital belongs to

    1. Group H (Storage)
    2. Group A (Residential)
    3. Group C (Institutional)
    4. Group E (Business)
    Answer

    C. Group C (Institutional)

    Hospitals are institutional occupancies.

14. Under NBC, shops and malls belong to

    1. Group J (Hazardous)
    2. Group E (Business)
    3. Group G (Industrial)
    4. Group F (Mercantile)
    Answer

    D. Group F (Mercantile)

    F = Mercantile; E = Business (offices).

15. Under NBC, a high-rise building is generally one of height

    1. 5 m or more
    2. 8 m or more
    3. 15 m or more
    4. 30 m only
    Answer

    C. 15 m or more

    15 m and above is the usual meaning.

16. A habitable room should have a minimum area of

    1. 9.5 sq m
    2. 4.5 sq m
    3. 15 sq m
    4. 1.8 sq m
    Answer

    A. 9.5 sq m

    Typical NBC minimum for a habitable room.

17. The typical minimum height of a habitable room is

    1. 1.5 m
    2. 2.75 m
    3. 3.5 m
    4. 2.0 m
    Answer

    B. 2.75 m

    2.75 m is the typical minimum.

18. The typical minimum area of a kitchen is

    1. 9.5 sq m
    2. 1.1 sq m
    3. 12 sq m
    4. 4.5 sq m
    Answer

    D. 4.5 sq m

    Kitchen minimum 4.5 sq m, width 1.5 m.

19. The typical minimum area of a water closet (WC) is

    1. 1.1 sq m
    2. 9.5 sq m
    3. 4.5 sq m
    4. 0.5 sq m
    Answer

    A. 1.1 sq m

    WC minimum 1.1 sq m, width 1.0 m.

20. Ramps for persons with disabilities should not be steeper than

    1. 1 in 4
    2. 1 in 12
    3. 1 in 6
    4. 1 in 2
    Answer

    B. 1 in 12

    The standard maximum slope is 1:12.

21. Which Indian Standard covers plain and reinforced concrete?

    1. IS 456
    2. IS 800
    3. IS 1893
    4. IS 875
    Answer

    A. IS 456

    IS 456 is the concrete code.

22. Which Indian Standard covers general construction in steel?

    1. IS 1893
    2. IS 13920
    3. IS 456
    4. IS 800
    Answer

    D. IS 800

    IS 800 is the steel code.

23. Earthquake-resistant design criteria are given in

    1. IS 800
    2. IS 456
    3. IS 1893
    4. IS 875
    Answer

    C. IS 1893

    IS 1893 is the seismic code.

24. The code for loads other than earthquake (dead, imposed, wind, snow) is

    1. IS 456
    2. IS 875
    3. IS 1893
    4. IS 13920
    Answer

    B. IS 875

    IS 875 covers these loads.

25. M20 concrete has a characteristic compressive strength of

    1. 20 N per sq mm at 28 days
    2. 200 N per sq mm
    3. 20 kN per sq m at 7 days
    4. 2 N per sq mm
    Answer

    A. 20 N per sq mm at 28 days

    The number is strength in N/sq mm at 28 days.

26. The nominal mix of M20 concrete (cement : sand : aggregate) is

    1. 1 : 3 : 6
    2. 1 : 2 : 4
    3. 1 : 1.5 : 3
    4. 1 : 1 : 2
    Answer

    C. 1 : 1.5 : 3

    M20 = 1:1.5:3; M15 = 1:2:4; M25 = 1:1:2.

27. The unit weight of reinforced concrete is taken as

    1. 50 kN per cubic metre
    2. 10 kN per cubic metre
    3. 2.5 kN per cubic metre
    4. 25 kN per cubic metre
    Answer

    D. 25 kN per cubic metre

    RCC is about 25 kN per cubic metre.

28. A slab 5 m x 4 m and 150 mm thick is made of RCC (25 kN per cubic metre). Its total self weight is

    1. 37.5 kN
    2. 75 kN
    3. 750 kN
    4. 15 kN
    Answer

    B. 75 kN

    0.15 x 25 x 20 = 75 kN.

29. A floor of 6 m x 5 m carries an imposed load of 2 kN per sq m. The total imposed load is

    1. 60 kN
    2. 600 kN
    3. 12 kN
    4. 30 kN
    Answer

    A. 60 kN

    2 x 30 = 60 kN.

30. A slab 4 m x 3 m has thickness 100 mm. Its self weight using 25 kN per cubic metre is

    1. 300 kN
    2. 12 kN
    3. 30 kN
    4. 3 kN
    Answer

    C. 30 kN

    0.1 x 25 x 12 = 30 kN.

31. For a live electrical fire, which extinguishing medium should NOT be used?

    1. Clean agent gas
    2. Dry powder
    3. Carbon dioxide
    4. Water
    Answer

    D. Water

    Water conducts electricity.

32. Consider the statements. 1. NBC is published by the Bureau of Indian Standards. 2. NBC applies by itself in every town without adoption by local rules. Which is/are correct?

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    NBC is a model code; it binds when adopted.

33. Consider the statements. 1. IS 456 covers reinforced concrete. 2. IS 800 covers steel construction. Which is/are correct?

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both codes are correctly matched.

34. Consider the statements. 1. Part 4 of NBC 2016 deals with fire and life safety. 2. Part 6 of NBC 2016 deals with building materials. Which is/are correct?

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Part 6 is structural design; Part 5 is materials.

35. Consider the statements. 1. High-rise buildings need stricter fire norms. 2. High-rise is defined by the number of rooms in a building. Which is/are correct?

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    High-rise is defined by height, usually 15 m or more.

36. Consider the statements. 1. Group D covers assembly buildings. 2. Group E covers educational buildings. Which is/are correct?

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Educational is Group B; E is Business.

37. Consider the statements. 1. Dead load is the weight of the structure itself. 2. Imposed load includes people and furniture. Which is/are correct?

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both definitions are correct.

38. Consider the statements. 1. NBC sets minimum standards. 2. Local bodies may add their own building rules. Which is/are correct?

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    NBC is a minimum model; local rules are added.

39. Consider the statements. 1. Volume 1 of NBC 2016 has Parts 0 to 6. 2. Volume 2 of NBC 2016 has Parts 7 to 12. Which is/are correct?

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    The split is Parts 0-6 and 7-12.

40. Consider the statements. 1. IS 1893 is the code for earthquake-resistant design. 2. IS 1893 is the code for steel design. Which is/are correct?

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    IS 800 is steel; IS 1893 is earthquake.

41. Match the NBC part with its subject. P. Part 4 Q. Part 6 R. Part 9 1. Plumbing services 2. Fire and life safety 3. Structural design

    1. P-3, Q-1, R-2
    2. P-2, Q-3, R-1
    3. P-1, Q-2, R-3
    4. P-2, Q-1, R-3
    Answer

    B. P-2, Q-3, R-1

    Part 4 fire; Part 6 structural; Part 9 plumbing.

42. Match the occupancy with its group. P. Residential Q. Educational R. Storage 1. Group B 2. Group H 3. Group A

    1. P-2, Q-1, R-3
    2. P-1, Q-3, R-2
    3. P-3, Q-2, R-1
    4. P-3, Q-1, R-2
    Answer

    D. P-3, Q-1, R-2

    Residential A; Educational B; Storage H.

43. Match the IS code with its subject. P. IS 456 Q. IS 875 R. IS 13920 1. Loads 2. Ductile detailing for earthquakes 3. Concrete

    1. P-3, Q-2, R-1
    2. P-1, Q-3, R-2
    3. P-2, Q-1, R-3
    4. P-3, Q-1, R-2
    Answer

    D. P-3, Q-1, R-2

    IS 456 concrete; IS 875 loads; IS 13920 ductile detailing.

44. Which part of NBC 2016 deals with safety at construction sites, scaffolding and excavation?

    1. Part 1
    2. Part 7
    3. Part 10
    4. Part 12
    Answer

    B. Part 7

    Part 7 is construction management, practices and safety.

45. The Code is a

    1. Central Act with penal powers in all towns
    2. tax law for property
    3. court judgment on land disputes
    4. model code that local bodies adopt in their building rules
    Answer

    D. model code that local bodies adopt in their building rules

    NBC is recommendatory until adopted.