Last edited 25 Nov 2020

International Building Code (IBC)

Building codes are regulations that set out the standards to which buildings and other structures must conform. The International Building Code (IBC) is one of the codes established in the US by the International Code Council (ICC) and is applied by most of the country’s jurisdictions as well as internationally, although it can be amended to reflect local conditions and legislation.

IBC can be applied to most types of new buildings and is intended to ensure efficient and flexible building designs that protect health and safety and encourage the use of technological advances.

It requires that buildings and structures are classified under two categories:

Use and occupancy.
Type of construction.

Under use and occupancy there are several groups and subgroups that define a building’s specific use and are numbered based on the perceived risk the building poses to its occupants (the lower the number, the higher the risk). They are defined as follows:

OCCUPANCY GROUP	SUBGROUPS	USES
Assembly	A-1 (theatres, halls for performing arts) A-2 (restaurants) A-3 (worship and other recreation) A-4 (indoor arena) A-5 (stadiums)	Places used for people gathering.
Business	B	Places used for providing services (e.g. banks, government buildings, police stations, offices).
Educational	E	Schools and day care centres.
Factory	F1 and F2	Places used for manufacturing, packaging, repairing, etc.
High Hazard	H-1, H-2, H-3, H-4, and H-5	Places involving hazardous materials (production, storage, etc.).
Institutional	I-1, I-2, I-3, and I-4	Places where people are unable to leave without assistance (e.g. hospitals, care homes, prisons),
Mercantile	M	Commercial (e.g. shops, department stores, etc.).
Residential	R-1, R-2, R-3, and R-4	Places providing overnight accommodation (e.g. houses, hotels, apartments, hostels, etc.).
Storage	S-1 and S-2	Places where things are stored (e.g. warehouses, car parks, garages, etc.).
Utility and miscellaneous	U	Accessory structures and others (e.g. towers, barns, cooling towers, stables, tanks, retaining walls, etc.).

Buildings can also be classified as a mixed occupancy type if they are occupied by more than one group type, and the different parts must conform to the codes for those areas. For example, a shopping centre with an underground car park will need to conform to both Group M and Group S.

The type of construction identifies the type of materials utilised for constructing the building or structure and classifies the level of combustibility and fire resistance associated with its elements (including primary structural frame, exterior and interior load-bearing and non-load-bearing walls, floor and roof). These are categorised as follows:

Types I and II: Building elements are made of noncombustible materials.
Type III: Exterior walls are made of noncombustible materials, the interior elements are made of any permissible material.
Type IV: Exterior walls are made of noncombustible materials, interior elements are made of, or incorporate, timber.
Type V: Structural elements comprise any permissible materials (A: Fire-resistance rated construction. B: Non fire-resistance rated construction).