The International Building Code (IBC) is the basis for all aspects of structural design requirements and code guidelines that are used in national, state and local building codes. Part of this standard of codes applies to occupancy loads for the different classifications of buildings. These considerations are dictated by usage of the building, the size of the building and its various rooms and divisions, and the safe limits of occupying a building at any given time.
The limits on occupancy loads for the various types of uses of a building are divided into classifications by the IBC. One category is for rooms and structures for assembly of persons include fixed seating establishments such as theaters and music venues, eating and drinking establishments, churches and other meeting groups, and areas for viewing indoor and outdoor events. Other categories designate uses for office space, manufacturing, institutional entities, merchant stores, all types of residences, hazardous material storage and storage facilities for other materials.
Aspects of Occupancy
An occupancy load is dictated by the size of the room or structure and the number of persons who can safely occupy the area. The function of the room or structure will be a deciding factor as to the allowed occupancy load as well. These calculations are based on the practical application of available floor space for persons and necessary accoutrements in the area while leaving room for reasonable egress and access to fire escapes and other entries and exits.
General IBC Guidelines for Occupancy Loads
The basic formula for figuring occupancy loads is dividing the square footage of an area by the number of persons who will be in the area at any given time for the purposes intended. This general guideline is established by the IBC and is subdivided into specific usage factors. In some cases, these guidelines will be adjusted to allow for those rooms or structures that are to be used for a variety of assembly needs.
Other Variables in Occupancy Loads
Some IBC requirements for occupancy loads specifically address certain uses. These requirements are occasionally updated as new types of business formats become part of the public interest, yet basic IBC guidelines will apply regardless of the use. For instance, different types of entertainment venues must be identified as to occupancy loads, such as a bowling alley or a public swimming facility. The activity that will take place in this category of assembly area will affect the occupancy load requirements of the IBC.
Examples of IBC Occupancy Rules
The IBC occupancy requirements reflect the need for practical and safe usage for many different applications. One example of this might refer to occupancy loads of an art gallery. This type of venue would be considered a mercantile occupancy, since artwork is being displayed for commercial purposes. This would be reflected in the IBC requirement of 30 square feet of space per occupant. On the other hand, an artist's studio or workspace would be considered a business occupancy that would allow up to 100 square feet per occupant.