Chapter 3 of the 2006 IBC simplified:
Chapter 3 of the code considers the risk to occupants of buildings as well as the probability of property loss. For the most part, the level of risk to occupants within a building is dependent on the number of occupants, the density of such occupants, their age, their capability of self preservation and their familiarity with, and control over, the conditions to which they are subjected.
With regard to protection against property loss, the code considers not only the internal hazards but also exposures to and from adjacent buildings and the combined hazard of buildings in a neighborhood.
Regulations are based on previous experience with adjustments for current technology. In developing regulations, consideration is given to the rate of fire spread, its intensity and duration. The code recognizes the performance that may be expected for materials common in today's marketplace and recognizes materials and methods of construction that are economically feasible. Finally, the code considers the facilities that are necessary to operate and maintain a building, which cannot impinge on the health and general welfare of a community's citizens. The bulk of the requirements in the balance of the code are greatly dependent on the proper application of this chapter.
"¢ Proper occupancy classification is a critical decision in determining code compliance.
"¢ Uses are classified by the code into categories of like hazards, based on the risk to occupants of the building as well as the probability of property loss.
"¢ Group A occupancies include rooms and buildings with an occupant load of 50 or more, utilized for the gathering together of persons for civic, social or religious functions; recreation, food or drink consumption; or similar activities.
"¢ The hazards unique to assembly uses are based primarily on the large occupant loads and the concentration of occupants into very small areas.
"¢ Business uses, such as offices, are classified as Group B occupancies and are considered moderate-hazard occupancies.
"¢ Group E occupancies are limited to schools for students through 12th grade and most day-care operations.
"¢ Manufacturing occupancies, classified as Group F, are defined based upon whether or not the materials being produced are combustible or noncombustible.
"¢ Group H occupancies are heavily regulated because of the quantities of hazardous materials present in use or storage.
"¢ Where amounts of hazardous materials are limited in control areas to below the maximum allowable quantities, the occupancy need not be considered a Group H.
"¢ Both physical hazards and health hazards are addressed under the requirements for Group H occupancies.
"¢ Institutional occupancies, classified as Group I, are facilities where individuals are under supervision and care because of physical limitations of health or age, or that house individuals whose personal liberties are restricted.
"¢ Group M occupancies include both sales rooms and motor fuel-dispensing facilities.
"¢ Residential Group R occupancies are partially regulated based upon occupant load or number of units, as well as the occupants' familiarity with their surroundings.
"¢ Group S occupancies for storage are viewed in a manner consistent with Group F manufacturing uses.
"¢ Group U occupancies are utility in nature and are seldom, if ever, occupied.