More than 3,000 people die in fires each year, and another 17,500 are injured, according to 2011 statistics provided by the U.S. Fire Administration. The International Fire Code and local building codes provide guidance on building occupancy standards, which are designed to allow occupants to safely exit a building during an emergency. Understanding and obeying these standards and related fire codes can help you avoid a tragedy.
The occupancy level of a space, or the maximum number of people the space can safely accommodate, depends on a variety of factors. Primarily based on square footage, occupancy also depends on the number and location of exits, whether the building has a sprinkler system, what the building is used for and whether hazardous materials are present.
To estimate the occupancy of a space, divide the square footage of the room by the square footage required per person. This square footage per person varies significantly depending on the type of building, and can be found in Section 1004 of the International Fire Code. For example, classrooms require 20 square feet per person, while retail establishments require 60 square feet per person. In cases where a space is used for multiple purposes, always observe the stricter, or lower occupancy level, of the two.
The route you must take to exit once you leave a space can further decrease occupancy levels. Narrow pathways or stairwells, long egress paths and other factors may lower occupancy loads. Even very large spaces with only a single exit cannot legally accommodate more than 50 people due to lack of alternate means of egress. For example, a 2000-square foot assembly room at a school could accommodate 100 students based on square footage alone. If that room only has a single exit, the International Building Code limits occupancy to 50 people to make it more likely that everyone in the room will have time to exit if a fire takes hold.
When determining fire safety and occupancy loads, your local fire marshal represents the ultimate authority and has the final say in all matters. Consult your fire marshal for help determining occupancy load or to determine how to make a structure safer for occupants during an emergency. Keep in mind that the International Fire Code is not law; it serves as the standard for local building codes throughout the United States, but many state and local governments maintain even stricter standards. Check your local codes for more information.