Chapter 14 Commercial Interior Design Applications 523 Copyright Goodheart-Willcox Co., Inc. D E S I G N E R M A T H S K I L L S Codes, Occupancy, and Fire Exits Daily people move in and out of supermarkets, hotels, malls, restaurants, medical facilities, entertainment venues, and even amusement parks with a sense of confidence, knowing that public spaces are regulated for health and safety by international building codes. Fire codes and safety regulations are the result of lessons learned from horrific commercial fi res resulting in staggering numbers of fatalities. Causes for these fatalities include fl ammable materials, toxic fumes, inoperable doors, blocked hallways and exits, props, faulty wiring, inappropriate working conditions, and projects completed without permits or inspections. Two critical design components when addressing safety to adequately serve the number of occupants in specific spaces include 1. establishing maximum occupancy limits 2. designing an appropriate emergency exit system— known as the means of egress Maximum occupancy limits can be determined from the International Building Codes (IBC). Its classification system categorizes spaces based on function (for example, airport terminals, bowling centers, courtrooms, day care, commercial kitchens, retail malls, warehouses and private residences). Using fl oor area allowances per occupant, known as Occupant Load, the IBC provides the following method for calculating maximum occupancy limits. Size of Space Function of Space Occupant Load Factor* Maximum Occupancy 1200 sq. ft. Library reading rooms 50 net** 1200 sq. ft. ÷ 50 net load = 60 occupants 2000 sq. ft. Assembly hall without fi xed seats (standing space) 5 net 2000 ÷ 5 = 400 occupants 2000 sq. ft. Airport terminal— baggage claim area 20 gross*** 2000 ÷ 20 = 100 occupants 13,448 sq. ft. Skating rinks, swimming pools (average public pool is 82 ft. × 164 ft. = 13,448 ft.) 50 gross 13,448 ÷ 50 gross = 692 occupants 512 sq. ft. Stages and platforms 15 net 512 ÷ 15 = 39 people 644 sq. ft. Assembly unconcentrated (with tables and chairs) 15 net 644 ÷ 15 = 43 people Once the designer calculates the maximum occupancy, the means of egress—the unobstructed exit system—must be addressed. For all portions of a building that can be occupied, design decisions are determined by the following three components of egress: ■ Exit access is the area leading occupants of a building to exits (for example, a corridor, aisle, pathway, stairwell, or ramp). On a plane, travelers are asked to stow all items securely under their seats or in overhead bins to keep the exit access—the space under a passenger’s feet and the aisle—free of interference. Elevators, escalators, and moving walks cannot be included in the egress system. ■ Exits are exterior exit doors at ground level, exit passage ways, exterior exit stairs, and/or exit ramps. ■ Exit discharge is the area that provides direct access to a lawn, courtyard, street, sidewalk, or open space, and must be large enough to accommodate the building occupants likely to use the exit route at any one time. The three components of egress apply to all portions of a building that people can occupy including spaces such as boiler rooms, locker rooms, and meeting rooms. No building element or object can obstruct the means of egress at any time. For example, a piano cannot temporarily block a backstage fi re exit. Likewise, stairwells cannot provide temporary storage for any reason. Proper maintenance of the egress system must occur for the life of the building. *Occupant Load Factor is the net fl oor area per occupant (sq. ft.). **Net is the actual workable space i.e., a classroom, offi ce, stage. ***Gross is the outside dimensions of a building minus the exterior walls, atriums, mechanical closets providing a refi nement in the occupant load determination. (Continued)