NBC 2016:2016 Part 1 is the Indian Standard (BIS) for national building code of india 2016 - definitions. Part 1 of NBC 2016 is the definitions volume. It collects the technical vocabulary referenced by the remaining twelve Parts so that a term used in Part 4 (fire safety) carries the same meaning when it appears in Part 6 (structural design) or Part 9 (plumbing). The Part itself contains no design rules — it is a reference glossary. Definitions cover building classifications, occupancy groups, heights and floor levels, open spaces, setbacks, structural elements, and service systems. For any Part-specific term that is not found here, the individual Part may carry its own local definitions section.
Consolidates the terms and definitions used throughout all Parts of NBC 2016, ensuring consistent interpretation of technical language across planning, design, construction, and facility management provisions.
NBC Part 1 carries the master definitions. Numerical thresholds shown here are the values referenced by other Parts; verify exact clause locations in the latest amendment.
| Reference | Value | Clause |
|---|---|---|
| Habitable room — defined min area (single-room dwelling)— definition references Part 3 Cl. 5.1.1 | 9.5 m² | Part 3, Cl. 12.3.1 |
| Habitable room — defined min width | 2.4 m | Part 3, Cl. 12.3.1 |
| High-rise building — height threshold— or above 4 storeys; triggers Part 4 fire requirements | ≥15 m | Part 2, Cl. 3.1.66 |
| Low-rise building — height ceiling | ≤15 m / G+4 | |
| Mezzanine floor — max area (% of room below) | ≤ 1/3 of room area | Part 3, Cl. 12.11 |
| Mezzanine — min clear height above and below | 2.2 m each | Part 3, Cl. 12.11 |
| Loft — max area (% of room) | ≤ 25% of room area | Part 3, Cl. 12.10 |
| Loft — min clear height | 1.5 m (min) – 1.75 m | Part 3, Cl. 12.10 |
| Basement — min clear height | 2.4 m | Part 3, Cl. 12.12.1 |
| Plinth — defined as height above— min plinth height set by Part 3 (450 mm) | Surrounding ground level | Part 2, Cl. 3.1.99 |
| Storey — typical floor-to-floor reference | ≥ 2.75 m floor-to-ceiling (habitable) | Part 3, Cl. 12.3.1 |
| Building line / control line — setback origin | Measured from plot boundary | Cl. 3.1.22 |
| Floor Area Ratio (FAR / FSI) — definition— numerical FAR set by State DCR | Built-up area ÷ plot area | Cl. 3.1.50 |
| Ground coverage — definition | Plinth-level built area ÷ plot area (%) | Part 3, Cl. 2.31 |
| Staircase riser & tread (residential)— Stricter norms apply to public/assembly buildings (150mm riser, 300mm tread). | ≤ 190 mm (riser), ≥ 250 mm (tread) | Part 3, Cl. 4.8.3 |
| Ramp slope for accessibility— For ramps intended for use by persons with disabilities. | 1:12 (max gradient) | Part 3, Annex C-4.1 |
| Standard car parking space size— Excludes driveways and maneuvering areas. | 2.5 m x 5.0 m (min) | Part 3, Cl. 7.2.1 |
| Natural ventilation opening area— Refers to aggregate openable area for habitable rooms. | ≥ 12.5% of floor area (1/8th) | Part 8, Sec 1, Cl. 5.2.1.1 |
| Minimum WC compartment area— For a compartment containing only a water-closet. | 1.1 m² (with 0.9 m min width) | Part 3, Cl. 4.10.1 |
| Travel distance to fire exit— Example for educational buildings (Group B) with a single escape path. Varies by occupancy. | 22.5 m (max) | Part 4, Table 7 |
| Mandatory lift/elevator provision height— Lifts are required in all buildings exceeding this height. | > 15 m building height | Part 3, Cl. 4.14.1 |
| Minimum corridor or passage width— For residential buildings. Wider corridors required for other building types. | 1.0 m | Part 3, Cl. 4.7.1 |
| Parameter | IS Value | International | Source |
|---|---|---|---|
| High-Rise Building Definition Threshold | Building height ≥ 15 m | Building with an occupied floor > 75 ft (≈ 23 m) above lowest level of fire dept. vehicle access | IBC 2024 |
| Mandatory Refuge Area Requirement | Yes, for buildings > 24m, at 24m and then every 15m. Area is 0.3 m²/person or 15 m² min. | No specific prescriptive requirement; addressed by other means like evacuation elevators or additional stairwells. | IBC 2024 |
| Min. Corridor Width (Institutional/Hospitals) | 2.0 m for non-ambulatory patients; 2.4 m if for stretcher movement | 96 inches (≈ 2.44 m) in new healthcare occupancies | NFPA 101:2024 |
| Max. Travel Distance (Business Occupancy, Sprinklered) | 45 m | 300 ft (≈ 91 m) | NFPA 101:2024 |
| Fire Resistance of Exit Stair Enclosure (High-Rise) | 2 hours | 2 hours | IBC 2024 |
| Automatic Sprinkler Trigger (New Hotels) | Mandatory if height > 15 m | Required in all new hotels, regardless of height (with few exceptions for small buildings) | NFPA 101:2024 |
| Ramp Slope (Means of Egress) | Maximum 1 in 10 (10%) | Maximum 1 in 12 (≈ 8.3%) | IBC 2024 |