524 Interior Design Copyright Goodheart-Willcox Co., Inc. systems, dead-end corridors may not exceed 20 feet. In buildings with sprinkler systems, these corridors may not exceed 50 feet. The designer plans large circulation paths around escalators, elevator banks, and stairwells. Security and emergency systems, ADA, and codes for fi re safety must all factor into the design plan. Some of the issues that impact systems and circulation paths include ■ Number of end users. The public can be several hundred or thousands. ■ Wayfinding strategies. Upon entry of public building, the expectation is that a person can easily self-guide from point A to point B and back out again. ■ Safety and security. Safely and securely moving occupants through the space and offering effi ciency in customer service. ■ Health of end users. Use a design approach that incorporates physical activity into the design plan for building and neighborhoods. A designer must analyze the circulation needs and develop a design that enhances public safety and comfort of the end user. Some common strategies include ■ Common paths of egress travel, including analysis of the distance people will travel before they have an option to take another path to safety. ■ Egress corridors with a minimum of 44 inches and whether or not the space has sprinklers. For a commercial building with sprinklers, 44-inch wide corridors can serve fl oors up to 22,000 square feet. As square footage increases on each fl oor, wider corridor widths are a requirement. The higher the building, the wider the hallways must be at lower levels to address the volume of people exiting at the same time. ■ Most organizations require at least two exit doors from its space, although offi ce areas less than 3,000–5,000 square feet may provide only one exit door depending on code. D E S I G N E R M A T H S K I L L S Codes, Occupancy, and Fire Exits (Continued) According to the Occupational Safety & Health Administration (OSHA), “…more than two exit routes must be available in a workplace if the number of employees, the size of the building, its occupancy, or the arrangement of the workplace is such that all employees would not be able to evacuate safely during an emergency.” When designing the means of egress, a designer requires additional information about a specific property to determine the exact number of exits. The designer considers the number of fl oors, seating (fixed seats, benches, and booths), door direction, travel distance to an exit, and the distance between exits. Posting the maximum occupancy of an assembly area is a requirement. This avoids overcrowding which would compromise an evacuation. When designing a space with two or more exits, you must know the maximum distance of the space, and then calculate it based on whether a sprinkler system is present. To determine the maximum distance in a space (for example, in a cafeteria), you measure the furthest distance in the space (see diagram) then calculate it with or without a sprinkler system. If fi re or smoke blocks one exit, the occupants can safely move away from the hazardous conditions evacuating through the second exit. If there is no sprinkler system, divide the maximum distance of the space by two. 80’-0” ÷ 2 = 40’-0” distance between exits. If there is a sprinkler system, divide the maximum distance by three. 80’-0” ÷ 3 = 20’-7” distance between exits Additional detail information about the means of egress for specific commercial and residential buildings is available online by searching OSHA or the International Fire Code. 80’-0”