4. Types Of Building

A building is a structure with walls and a roof situated in a specific location more or less permanently. Over history, buildings have evolved in various sizes, forms, and applications based on ground conditions, climate, construction materials, aesthetic considerations, and specific human needs. In civil engineering, buildings are systematically classified based on their usage (occupancy), the method by which they transfer structural loads, and their overall height.

1. Classification Based on Occupancy and Usage

Buildings are primarily categorized according to the nature of their daily usage and the occupants they serve. National Building Code (NBC) classify buildings into 9 distinct occupancy groups.

Here is the comprehensive table detailing the sub-categorizations for each main occupancy group:

Main Group	Sub-Group	Type of Building / Characteristics
Group A: Residential Buildings	A-1	Lodging and rooming houses.
	A-2	One or two family private dwellings.
	A-3	Dormitories.
	A-4	Apartment houses.
	A-5	Hotels.
	A-6	Starred Hotels.
Group B: Educational Buildings	B-1	Schools up to senior secondary level.
	B-2	All others/training institutions.
Group C: Institutional Buildings	C-1	Hospitals and sanatoria.
	C-2	Custodial institutions.
	C-3	Penal and mental institutions.
Group D: Assembly Buildings	D-1	Buildings with stage and fixed seats over 1,000 persons.
	D-2	Buildings with stage and fixed seats up to 1,000 persons.
	D-3	Buildings without a permanent stage, accommodation for 300 or more persons, and no permanent seating arrangements.
	D-4	Buildings without a permanent stage, accommodation less than 300 persons, and no permanent seating arrangements.
	D-5	Temporary structures designed for assembly.
	D-6	Shopping malls with multiplexes and food courts.
	D-7	Underground and elevated mass rapid transit system.
Group E: Business Buildings	E-1	Offices, banks, professional establishments.
	E-2	Laboratories, outpatient clinics, research establishments, libraries, and test houses.
	E-3	Electronic data processing centres, computer installations, information technology parks, and call centres.
	E-4	Telephone exchanges.
	E-5	Broadcasting stations, T.V. stations, and air traffic control towers.
Group F: Mercantile Buildings	F-1	Shops, stores, departmental stores (area up to 500 m²).
	F-2	Shops, stores, departmental stores (area >500 m²).
	F-3	Underground shopping centres.
Group G: Industrial Buildings	G-1	Buildings used for low hazard industries.
	G-2	Buildings used for moderate hazard industries.
	G-3	Buildings used for high hazard industries.
Group H: Storage Buildings	None specified	General storage facilities; the referenced NBC summary does not list specific sub-divisions for this group.
Group J: Hazardous Buildings	None specified	Facilities handling highly combustible or explosive materials; the referenced NBC summary does not list specific sub-divisions for this group.

• Residential Buildings: Structures where people live and conduct their daily activities. Examples include houses, villas, flats, apartments, lodges, hostels, and hotels.
• Educational Buildings: Facilities dedicated to learning and educational purposes, such as schools, colleges, and libraries.
• Assembly Buildings: Spaces designed for large gatherings, entertainment, or religious purposes. Examples include cinemas, temples, and churches.
• Institutional Buildings: Facilities established for medical, physical, or mental health care and treatments, such as hospitals and sanatoria.
• Business Buildings: Structures utilized for conducting commercial activities and providing services, including banks and shops.
• Storage Buildings: Facilities specifically designed to safely store materials, goods, or agricultural products like wheat and vegetables. Examples include warehouses and cold storage units.
• Hazardous Buildings: Highly specialized structures built to store dangerous, toxic, or volatile substances, such as acids or uranium.

2. Classification Based on Structural Load Transfer

From a structural engineering perspective, the super structures of buildings are classified by how they safely transfer loads (like the weight of the roof, floors, and the structure itself) down to the foundation:

• Load Bearing Structures: In these buildings, the load from the roof and floors is transferred vertically downward directly through the masonry walls to the foundation. Beams and columns are generally not used to bear the primary structural loads. This method is most economical for residential buildings up to three stories (Ground + 2 floors) and is suited for buildings where room dimensions are relatively small.

• Framed Structures: In this modern construction type, a framework of reinforced cement concrete (R.C.C.) or steel columns, beams, and slabs is built first to carry all the loads. The walls are built afterward merely to partition the living spaces and only carry their own self-weight. Framed structures are essential when a building has many stories or when large, open, wall-free areas are required.

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3. Classification Based on Height (Tall Structures)

With advancements in engineering, buildings are also classified by their vertical scale:

• High-Rise Buildings: According to the National Building Code of India, any building with a height of 15 meters or more is classified as a high-rise, regardless of what it is used for.
• Skyscrapers: These are multi-story buildings that reach at least 100 meters (330 feet) in architectural height.
• Supertall and Mega-tall Skyscrapers: Buildings that exceed a height of 300 meters (984 feet) are classified as supertall skyscrapers, while those towering over 600 meters (1969 feet) earn the designation of mega-tall skyscrapers.