MEANS OF EGRESS

Section 1001 Administration

Section 1002 Definitions

Section 1003 General Means of Egress

Section 1004 Occupant Load

Section 1005 Means of Egress Sizing

Section 1006 Number of Exits and Exit Access Doorways

Section 1007 Exit and Exit Access Doorway Configuration

Section 1008 Means of Egress Illumination

Section 1009 Accessible Means of Egress

Section 1010 Doors, Gates, and Turnstiles

Section 1011 Stairways

Section 1012 Ramps

Section 1013 Exit Signs

Section 1014 Handrails

Section 1015 Guards

Section 1016 Exit Access

Section 1017 Exit Access Travel Distance

Section 1018 Aisles

Section 1019 Exit Access Stairways and Ramps

Section 1020 Corridors

Section 1021 Egress Balconies

Section 1022 Exits

Section 1023 Interior Exit Stairways and Ramps

Section 1024 Exit Passageways

Section 1025 Luminous Egress Path Markings

Section 1026 Horizontal Exits

Section 1027 Exterior Exit Stairways and Ramps

Section 1028 Exit Discharge

Section 1029 Assembly

Section 1030 Emergency Escape and Rescue

Key Points

This chapter establishes the basic approach to determining a safe exiting system for all occupancies. It addresses all portions of the egress system and includes design requirements as well as provisions regulating individual components, which may be used within the egress system. The chapter specifies the methods of calculating the occupant load that are used as the basis of designing the system and, thereafter, discusses the appropriate criteria for the number of exits, location of exits, width or capacity of the egress system, and the arrangement of the system. This arrangement is treated in terms of remoteness and accessibility of the egress system. The accessibility is handled both in terms of the system’s usability by building occupants and in terms of it being available within a certain maximum distance of travel. After having dealt with general issues that affect the overall system or multiple zones of the system defined as the exit access, exit, and exit discharge, the chapter then establishes the design requirements and components that may be used to meet those requirements for each of the three separate zones.

In interpreting and applying the various provisions of this chapter, it would help to understand the four fundamental concepts on which safe exiting from buildings is based:

1.   A safe egress system for all building occupants must be provided.

2.   Throughout the system, every component and element that building occupants will encounter in seeking egress from the building must be under the control of the person wishing to exit.

3.   Once a building occupant reaches a certain degree or level of safety, as that occupant proceeds through the exiting system, that level of safety is not thereafter reduced until the occupant has arrived at the exit discharge, public way, or eventual safe place.

4.   Once the exit system is subject to a certain maximum demand in terms of the number of persons, that system must thereafter (throughout the remainder of the system) be capable of accommodating that maximum number of persons.

Egress for individuals with physical disabilities is to be provided under the provisions of this chapter, primarily through the design of an accessible means of egress system. Because many of the elements composing the egress system (doors, landings, ramps, etc.) may also form part of the accessible routes as required by Chapter 11, such requirements must be referenced where applicable.

Section 1001 Administration

This section requires that every building or portion thereof comply with provisions of Chapter 10. In dealing with portions of buildings, it is important to understand that the code intends this chapter to apply to all portions that are occupiable by people at any time. Therefore, areas such as storage rooms and equipment rooms, although often unoccupied, will still be regulated under the provisions of the chapter.

In order to provide an approved means of egress at all times, it is critical that the exiting system be maintained appropriately. Section 1031 of the International Fire Code® (IFC®) regulates maintenance of the means of egress for the life span of the building. Should there be alterations or modifications to any portion of the building, Section 1001.2 mandates that the number of existing exits not be reduced, nor the capacity or width of the means of egress be decreased, below that level required by the IBC. Section 1104 of the IFC also provides a limited number of specific provisions addressing the means of egress in existing buildings.

A reference to the IFC provisions addressing fire safety, evacuation, and lockdown plans recognizes the need to provide consistent and effective fire- and life-safety operations during emergency conditions. Section 404 of the IFC requires the fire-safety and evacuation plans in those occupancies and building types as set forth in Section 403. These plans are required to include or address a number of different types of issues that may affect the egress of occupants from the building. Along with other items, these include the identification of potential hazards, exits, primary and secondary egress routes, and occupant assembly points, as well as establishing procedures for assisted rescue for people who are unable to use the general means of egress unassisted.

Section 1002 Definitions

Section 1002 lists a number of defined terms that are especially important to this chapter. As with most other terms defined in the code, the terms identified in Section 1002.1 are specific to the IBC and typically differ from their ordinarily accepted meanings. Further information on many of these means of egress terms is found in Chapter 2 as part of the discussion of those specific terms defined in the IBC.

Section 1003 General Means of Egress

The requirements and topics addressed in this section are used as basic provisions and are to be applied throughout the entire egress path as applicable. Examples of the types of general issues that are found here include ceiling height, protruding objects, floor surface, elevation change, and egress continuity. For consistency purposes, the provisions for ceiling height and protruding objects are identical to the accessibility criteria of ICC A117.1.

1003.2   Ceiling height.   In order to provide an exit path that maintains a reasonable amount of headroom clearance for the occupants, this section requires the means of egress to have a minimum ceiling height of 7 feet 6 inches (2,286 mm). The intent of the provision is to address all potential paths of exit travel that can be created based on multiple directions of egress and the layout of the room or space insofar as furniture, equipment, and fixtures are concerned. Any portion of the floor area of the building that can reasonably be considered a possible exit path should be provided with a minimum 7-foot 6-inch (2,286-mm) clear height, unless reduced by exceptions permitted for sloped ceilings, dwelling and sleeping units in residential occupancies, stairway and ramp headroom, door height, and protruding objects. Additional exceptions reduce the minimum required clear height to 7 feet 0 inches (2,134 mm) in parking garage vehicular and pedestrian traffic areas as well as above and below floors considered as mezzanines.

1003.3   Protruding objects.   Limitations are placed on the permitted projection of protruding objects for two purposes. First, to maintain an egress path that is essentially free of obstacles. Second, to provide a circulation path that is usable by all occupants, including those individuals with sight-related disabilities. For this reason, provisions regulate the accessibility concerns regarding protruding objects as well as the egress concerns. Note that projections into the required egress width and the minimum clear width of accessible routes are also limited by other provisions of the code.

1003.3.1   Headroom.   Consistent with the allowance for stair headroom and doorway height to be reduced below the required egress height of 7 feet 6 inches (2,286 mm), other portions of the egress system may likewise be reduced to a minimum height of 80 inches (2,032 mm). The reduction for signage, sprinklers, decorative features, structural members, and other protruding objects is limited to 50 percent of the ceiling area of the egress path. See Figure 1003-1. Though projections at an 80-inch (2,032-mm) height are not unusual to building occupants, it is necessary to maintain a majority of the egress system at 7 feet 6 inches (2,286 mm) or higher. Passage through a doorway may be further reduced in height to 78 inches (1,981 mm) at the door closer or stop. This reduction at doors is also permitted for accessibility purposes by Section 307.4 of ICC A117.1. Where a vertical clearance of 80 inches (2,032 mm) cannot be achieved, the reduced-height portion of such floor area cannot be used as a portion of the means of egress system. It is also necessary to provide some type of barrier that will prohibit the occupant from approaching the area of reduced height. This is of particular importance where the occupant is sight impaired, with no method other than a barrier to identify the presence of an overhead protruding object. The mandated barrier is to be installed so that the leading edge is no more than 27 inches (686 mm) above the walking surface, as shown in Figure 1003-2. By limiting the height of the barrier edge, it will be located in a manner so that a sight-impaired individual using a long cane will detect the presence of an obstruction and maneuver to avoid the hazard.

Figure 1003-1   Means of egress headroom.

Figure 1003-2   Reduced vertical clearance.

1003.3.2   Post-mounted objects.   Free-standing objects mounted on a post or pylon that are located along or adjacent to the walking surface are potential hazards, particularly to a sight-impaired individual. Objects such as signs, directories, or telephones that are mounted on posts or pylons are, therefore, limited to an overhang of 4 inches (102 mm) maximum if located more than 27 inches (686 mm), but not more than 80 inches (2,032 mm), above the floor level. By limiting the overhang to 4 inches (102 mm), a cane will hit the post or pylon prior to the individual impacting the mounted object. See Figure 1003-3. Free-standing objects mounted at or below 27 inches (686 mm) will fall within the cane-detection zone, and objects mounted at 80 inches (2,032 mm) or higher are sufficiently above the walking surface. Similar concerns are addressed where the obstruction is mounted between posts located more than 12 inches (305 mm) apart. Unless the lowest edge of the obstruction is at least 80 inches (2,030 mm) above the walking surface, it must be located within the cane recognition area extending from the walking surface to a height of 27 inches (686 mm).

Figure 1003-3   Post-mounted protruding objects.

1003.3.3   Horizontal projections.   Consistent with the other provisions for protruding objects, horizontal projections such as structural elements, fixtures, furnishings, and equipment are considered hazardous where they fall outside of the area where cane detection can identify them. Visually impaired individuals cannot detect overhanging objects when walking alongside them. Because proper cane techniques keep people some distance from the edge of a walking surface or from walls, a slight overhang of no more than 4 inches (102 mm) is not considered hazardous. An example of this provision is illustrated in Figure 1003-4. An exception permits handrails to protrude up to 4½ inches (114 mm).

Figure 1003-4   Limits of protruding objects.

Although the provisions of this section, as well as those in Sections 1003.3.1 and 1003.3.2, are primarily based on clearances established for accessibility purposes, their value to all users of any circulation path is considerable. Projections into the means of egress potentially could result in a reduced travel flow, resulting in longer evacuation times during emergency conditions. In addition, injuries are possible to individuals who fail to pay proper attention to where they are going.

1003.4   Floor surface.   As evidenced by the requirements for ceiling height and protruding objects, the potential for exit travel to be impeded by obstructions is addressed throughout Chapter 10. Various provisions attempt to eliminate the opportunity for hazards along the exit path to slow travel. This section recognizes one area that is often taken for granted when it comes to egress—the walking surface of the means of egress. It is typically assumed that a walking surface that provides adequate circulation, and often accessibility, throughout a building will be acceptable for egress purposes as well. Although this is usually true, it is stated in the code that the egress path should have a walking surface that is slip resistant and securely attached so there is no tripping or slipping hazard that would result in an obstruction of the exiting process. Although the regulation of floor surfacing materials is typically recognized for interior walking surfaces, the provision is also applicable to exterior egress paths. The performance criteria of this code section provide a basis for determining the appropriateness of any questionable exit discharge elements.

1003.5   Elevation change.   The code is concerned that along the means of egress there is no change in elevation along the path of exit travel that is not readily apparent to persons seeking to exit under emergency conditions. Therefore, along the means of egress, any change in elevation of less than 12 inches (305 mm) must be accomplished by means of a ramp or other sloping surface. A single riser or a pair of risers is not permitted. See Figure 1003-5. Steps used to achieve minor differences in elevation frequently go unnoticed and as a consequence can cause missteps or accidents.

Figure 1003-5   Longitudinal section through corridor or other exit path.

This limitation on the method for a change of elevation, however, does not apply in certain locations. Where exterior doors are not required to be accessible by Chapter 11, a single step of 7 inches (179 mm) or less in height is permitted by Exception 1 at such exterior doors in Groups F, H, R-2, R-3, S, and U. See Figure 1003-6. A second exception allows, under specific conditions, a stair with a single riser or with two risers and a tread at those locations not required to be accessible by Chapter 11. In this case, the risers and treads must comply with Section 1011.5, the tread depth must be at least 13 inches (330 mm), and a minimum of one complying handrail must be provided within 30 inches (762 mm) of the centerline of the normal path of egress travel on the stair. See Figure 1003-7. A third exception applies to seating areas not required to be accessible. Risers and treads may be used on an aisle serving the seating where a complying handrail is provided.

Figure 1003-6   Single step at exterior door.

Figure 1003-7   Elevation change.

1003.6   Means of egress continuity.   This section emphasizes that wherever the code imposes minimum widths on components in an exiting system, such widths are to be clear, usable, and unobstructed. Nothing may project into these required capacities and minimum widths so as to reduce the usability of the full dimension, unless the code specifically and expressly states that a projection is permitted. Two notable examples of permitted projections are doors, either during the course of their swing or in the fully open position, and handrails. The limitations on the amount of such projections are specified within the appropriate sections of the chapter. Additionally, this section places into code language one of the four basic concepts that were previously discussed—that once the exit system is subject to a certain maximum demand in terms of number of persons, that system must thereafter be capable of accommodating that maximum number of persons.

1003.7   Elevators, escalators, and moving walks.   For a variety of reasons, elevators, escalators, and moving walks are not to be used to satisfy any of the means of egress for a building. These building components are intended for circulation purposes and do not conform with the detailed egress requirements found in Chapter 10. The only exception is for elevators used as an accessible means of egress as addressed in Section 1009.4.

Section 1004 Occupant Load

1004.1   Design occupant load.   This section prescribes a series of methods for determining the occupant load that will be used as the basis for the design of the egress system. The basic concept is that the building must be provided with a safe exiting system for all persons anticipated in the building. The process for determining an appropriate occupant load is based on the anticipated density of the area under consideration. Because the density factor is already established by the code for the expected use, variations in occupant load are simply a function of the floor area assigned to that use. It is apparent that in many situations the occupant load as calculated is conservative in nature. This is appropriate because of the extent that the means of egress provides for life-safety concerns. The egress system should be designed to accommodate the worst-case scenario, based on a reasonable assumption of the building’s use.

1004.1.1   Cumulative occupant loads.   This provision mandates that the occupant loads are to be cumulative as the occupants egress through intervening spaces. Under the conditions of Section 1014.2, the path of travel through the intervening space must be discernable to allow for a continuous and obvious egress path. Egress travel is permitted to pass through complying adjoining rooms provided the design occupant load is increased to account for those potential occupants who are assigned to that specific egress path. See Figure 1004-1. Another common application occurs as users of the means of egress merge at aisles, corridors, or stairways, as shown in Figure 1004-2. Where alternative means of egress are provided, only the number of occupants assigned to each of the egress paths is used in the cumulative occupant load determination. See Figure 1004-3. Where significant occupant loads are anticipated such that a room or space requires at least two means of egress, the provisions of Section 1005.5 must also be considered for the proper distribution of the occupant load capacity.

Figure 1004-1   Combination occupant loads.

Figure 1004-2   Number of combination.

Figure 1004-3   Assignment of occupant load.

The practice of accumulating occupants along the means of egress also applies vertically where travel from a mezzanine level or a story leads into a room on an adjacent level, rather than directly into an enclosure for an interior exit stairway. Where travel occurs within the exit access portion of the means of egress system, occupant loads are to be cumulative vertically as well as horizontally. An example is shown in Figure 1004-4.

Figure 1004-4   Vertical accumulation of occupant load.

Where the means of egress occurs on interior exit stairways, Section 1005.3.1 indicates that the capacity of the exitways be based on the individual occupant loads of each story. In other words, the number of persons for which the capacity of the stairway is designed is not based on any cumulative total number of persons, but rather on the required capacity of the exits at each particular floor. In no case, however, shall exit capacity decrease along the path of egress travel. A more in-depth discussion of this issue is found in Section 1005.1 and is illustrated in Figure 1005-2. Where exiting occurs from a mezzanine, the provisions of Section 1004.1.1.2 apply rather than those of Section 1005.3.1. Section 1004.1.1.2 is also applicable where exit access stairways serve adjacent stories or floor levels.

Figure 1005-2   Reduction in actual width.

1004.1.2   Areas without fixed seating.   The vast majority of buildings contain uses that do not use fixed seating. Unlike auditoriums, theaters, and similar spaces, in most instances the maximum probable number of occupants may not be known. Therefore, the code provides a formula for determining an occupant load that constitutes the minimum number of persons for which the exiting system must be designed. As a consequence, the code refers to the number obtained by the formula as the design occupant load. Egress systems for all buildings or building spaces must be designed to accommodate at least this minimum number. Basic examples of the use of Table 1004.1.2 are illustrated in Figure 1004-5.

Figure 1004-5   Design occupant load.

As the person responsible for interpreting and enforcing the code, the building official will be called on to make decisions regarding the categories listed in Table 1004.1.2. Although Table 1004.1.2 contains occupant load factors that will serve the code user under most conditions, there will be occasions when either the table does not have an occupant load factor appropriate for the intended use or the occupant load factor contained in the table will not have a realistic application. In such instances, the building official has the authority to establish an appropriate occupant load factor or an appropriate occupant load for those special circumstances and those special buildings.

It may be meaningful to point out that the first column of Table 1004.1.2 is headed “Function of Space.” The categories listed in the first column are not the specific groups identified in Chapter 3 for the purpose of assigning an occupancy classification but are the basic generic uses of building spaces. It has been pointed out in the discussion of the various occupancy groups that it is possible to have a classroom classified as a Group E occupancy, a Group B occupancy, or, possibly, a Group A occupancy. In terms of occupant density, however, a classroom is a classroom, and it is reasonable to expect the same density of use in a classroom regardless of the occupancy group in which that classroom might be classified. Therefore, the table specifies that when considering classroom use, one must assume there is at least one person present for each 20 square feet (1.86 m²) of floor area.

In specifying how the occupant load is to be determined, the code intends that it is to be assumed that all portions of a building are fully occupied at the same time. It may be recognized, however, that in limited instances not all portions of the building are, in fact, fully occupied simultaneously. An example of this approach for support uses might include conference rooms in various occupancies or minor assembly areas such as lunch rooms in office buildings or break rooms in factories. It is important to note that the code does not provide for a method to address such conditions; thus, full occupancy should always be assumed. Only under rare and unusual circumstances should the building official ever consider reducing the design occupant load because of the nonsimultaneous use concept. In such situations, he or she must determine that there are support spaces that ordinarily are used only by persons who at other times occupy the main areas of the building; therefore, it is not necessary to accumulate the occupant load of the separate spaces when calculating the total occupant load of the floor or building. It is always necessary, however, to provide each individual space of the building with egress as if that individual space were fully and completely occupied.

Another type of support area that must be considered in occupant-load calculation includes corridors, closets, toilet rooms, and mechanical rooms. These uses are typical of most buildings and are to be included by definition in the gross floor area of the building. A quick review of Table 1004.1.2 will show that most of the uses listed are to be evaluated based on gross floor area, with no reduction for corridors and the like. However, a few of the listings indicate the use of the net floor area in the calculation of the occupant load. An example would be the determination of an occupant load in a school building. The building official should calculate the occupant load in such buildings using only the administrative, classroom, and assembly areas. It is generally assumed that when corridors, restrooms, and other miscellaneous spaces are occupied, they are occupied by the same people who are at other times occupying the primary use spaces.

The occupant load that can be expected in different buildings depends on two primary factors—the nature of the use of the building space and the amount of space devoted to that particular use. Different types of building uses have a variety of characteristics. Of primary importance is the density characteristic. Therefore, in calculating the occupant load of different uses, by means of the formula, the minimum number of persons that must be assumed to occupy a building or portion thereof is determined by dividing the area devoted to the use by that density characteristic or occupant load factor. The second column of Table 1004.1.2 prescribes the occupant load factor to be used with respective corresponding uses listed in the first column. The occupant load factor does not represent the amount of area that is required to be afforded each occupant. The IBC does not limit, except through the provisions of Section 1004.2, the maximum occupant load on an area basis. Rather, the occupant load factor is that unit of area for which there must be assumed to be at least one person present. For example, when the code prescribes an occupant load factor of 100 gross for business use, it is not saying that each person in an office must be provided with at least 100 square feet (9.29 m²) of working space. Rather, it is saying that, for egress purposes, at least one person must be assumed to be present for each 100 square feet (9.29 m²) of floor area in the business use. It is important to note that the floor area to be used in the application of Table 1004.1.2, both net and gross, is to include counters and showcases in retail stores, furniture in dwellings and offices, equipment in hospitals and factories, and similar furnishings. The floor areas occupied by furniture, equipment, and furnishings are taken into account in the occupant load factors listed in the table.

The numbers contained in the second column of Table 1004.1.2 represent those density factors that approximate the probable densities that can usually be expected in areas devoted to the respective functions listed. For this purpose, the occupant load factors are really a means of estimating the probable maximum density in the varying function areas. They have been developed over a period of years and, for the most part, have been found to consistently represent the occupant/furnishing densities that one might expect in building spaces devoted to the respective uses. See Application Examples 1004-1 and 1004-2 for two methods of occupant load determination.

The exception to this section allows for a reduction in the calculated design occupant load on a very limited case-by-case basis. The building official is granted authority for the discretionary approval of lesser design occupant loads than those established by calculation. Although the provision allows the building official to be accommodating by recognizing the merits of the specific project, its use should be limited to very unique situations such as extremely large manufacturing or warehousing operations. See Application Example 1004-3. Where the exception is enacted in order to reduce the occupant load, the building official will typically impose specific conditions to help ensure compliance. It is critical that the reasoning for the occupant load reduction be justified and documented.

1004.2   Increased occupant load.   The provisions of Section 1004.1.2 specify the method to be used in determining the anticipated occupant load for areas without fixed seating. The occupant load determined by this method is the minimum number of persons for which the exiting system must be designed. The provisions do not, as previously pointed out, intend that the maximum permitted occupant load be regulated or controlled on a floor-area basis other than in the manner described by this section.

Application Example 1004-1

Application Example 1004-2

Application Example 1004-3

The provisions of this section specify how the maximum permitted occupant load in a building or portion of the building is to be determined. Here, the approach is taken that the occupant load determined as previously provided may be increased where the entire egress system is adequate, in all of its parts, to accommodate the increased number. In no case, however, shall the occupant load be established using an occupant load factor of less than 7 square feet (0.65 m²) of floor space per person. See Application Example 1004-4.

Application Example 1004-4

In order to analyze any increased occupant load, the building official must carefully review all aspects of the arrangement of space as well as the details of the total egress system, not only from the immediate space but continuously through all other building spaces that might intervene. In many cases, a diagram will be required indicating the approved furnishing and equipment layout.

Although it is critical that the building’s means of egress system be designed to accommodate the increased occupant load, all other code requirements that are based on the number of occupants must also be reviewed based on the increased number. For example, if it is intended to increase the calculated occupant load of 258 in a Group A-3 conference facility to 340 occupants, all code requirements shall be applied based on the occupant load of 340. This would include the provisions of Section 903.2.1.3 that require an automatic sprinkler system, those of Section 907.2.1 mandating a manual fire alarm system, and the main exit requirements of Section 1029.2. An additional occupant-load-based provision that must be considered is that for plumbing fixtures.

1004.3   Posting of occupant load.   Where a room or space is to be used as an assembly occupancy, this section requires the posting of a sign indicating the maximum permitted occupant load. This sign serves as a reminder to the occupants of the space, as well as building employees, that any larger occupant load would create an overcrowded condition. In order to be effective, the sign must be conspicuously located near the main exit of the room or space, and must be permanently maintained. An example of an occupant load sign is shown in Figure 1004-6. Where multiple uses causing varying occupant loads are anticipated, it is appropriate to designate the maximum occupant load for each use, as shown in Figure 1004-7.

Figure 1004-6   Occupant load sign.

Figure 1004-7   Posting of occupant load.

1004.4   Fixed seating.   The method of calculating occupant load discussed to this point—that is, the formula that divides an appropriate occupant load factor into the amount of space devoted to a specific function—is used when dealing with building spaces without fixed seating. Where fixed seats are installed, the code specifies that the occupant load be determined simply by counting the number of seats. Although the code does not define the term fixed seats, it is intended by this term that the seats provided are, in fact, fastened in position, not easily movable, and maintained in those fixed positions on a more or less permanent basis. A primary example of a fixed-seat facility would be a performance theater. In determining the occupant load for this type of facility, only the number of fixed seats is used because the code also requires that the space occupied by aisles may not be used for any purpose other than aisles and, therefore, may not be used for accommodating additional persons. The aisle system within a fixed-seating facility is, in fact, the exiting system for those fixed seats and, as such, must remain unobstructed. Therefore, the code does not assume any occupancy in the areas that make up the aisles.

Under varying circumstances, fixed-seating assembly spaces may include other assembly areas capable of being occupied. Such areas could include wheelchair spaces, waiting areas, and/or standing room. Performance areas and similar spaces would also be evaluated and assigned an appropriate occupant load. The occupant load of all such areas must be added to that established for the fixed seating in the calculation of the total occupant load. An example is shown in Figure 1004-8. The inclusion of these additional occupiable areas provides for a more accurate determination of the potential number of persons who could occupy the room or space.

Figure 1004-8   Occupant load determination for fixed seating.

In addition to those fixed-seating arrangements where the seating is provided by a chair-type seat, there will be those that use continuous seating surfaces such as benches and pews. When this type of seating is provided, it is necessary to assume at least one person present for each 18 inches (457 mm) of length of seating surface. Where seating is provided by use of booths, as is frequently done in restaurants, it must be assumed that there is a person present for each 24 inches (610 mm) of booth-seating surface. If the booth seating is curved, the code specifies that the booth length be measured at the backrest of the seating booth. Where seating is provided without dividing arms, such as for benches and booths, it is reasonable to base the occupant load individually to each bench or booth. Similarly, it is appropriate to round the calculated occupant load down to the lower value, as this section only regulates each full 18 inches or 24 inches of width. See Application Example 1004-5.

The method for determining occupant load in a small restaurant is depicted in Application Example 1004-6.

1004.5   Outdoor areas.   Occupiable yards, patios, and courts that are used by occupants of the building must be provided with egress in a manner consistent with indoor areas. This provision is applicable to outdoor areas, including building rooftops, that are occupied for a variety of uses, but is primarily applied to outdoor dining at restaurants and cafés. The building official shall assign an occupant load in accordance with the anticipated use of outdoor areas. If an area’s occupants need to pass through the building to exit, the cumulative total of the outdoor area and the building shall be used to determine the exiting requirements. This concept is consistent with the provisions of Section 1004.1.1. See Figure 1004-9.

Figure 1004-9   Outdoor areas.

Application Example 1004-5

Application Example 1004-6

Another example that is becoming more common is that of secured exterior areas serving nursing homes (Group I-2) or assisted living facilities (Group I-1, R-3, or R-4). Such exterior spaces are often provided to enhance the livability of the facilities by providing outdoor spaces where the patients or residents are free to roam without individual supervision. When evaluating these spaces for egress purposes, there are several issues to consider. If the secured yard is provided with a means of egress independent of the facility, the gates must comply with all of the requirements for egress doors. Electric locking systems, delayed egress devices, sensor release devices, or electromagnetic locking systems installed in accordance with Sections 1010.1.9.6 through 1010.1.9.9, as applicable, would be permitted as a means of addressing occupant safety for these areas. Without compliant gates, the means of egress must be designed for travel back through the facility. The facility must also egress independent of the secured yard unless all means of egress from the secured exterior area comply with the code.

The judgment of the building official is very important to the application of these provisions because the building official must determine exactly what occupant load should be considered and to what degree the area is accessible and usable by the building occupants in order to establish the egress requirements. Some cases that will require judgment include large spaces that might have a very limited anticipated occupant load such as areas that are primarily for the service of the building. Where a portion of the required means of egress for the outdoor area is provided independent of travel back through the building, or where all of such required egress must pass through the building, the applicable provisions would be similar to those for travel through intervening spaces. The distribution of the occupant load from the outdoor area will depend on how many exits are required and how many means of egress paths are available.

1004.6   Multiple occupancies.   In many buildings there are two or more occupancies. Quite often, one or more of the egress paths from an individual occupancy will merge with egress paths from other occupancies. Within each individual occupancy, the means of egress shall be designed for that specific occupancy. However, where portions of the means of egress serve two or more different occupancies, the more restrictive requirements of the occupancies involved shall be met. An example might be where a sizable assembly occupancy shares an exit path with a business use. The more restrictive requirement for panic hardware would be applicable for any doors encountered along the shared egress route.

Section 1005 Means of Egress Sizing

1005.1   General.   This section establishes the method for sizing the capacity of the egress system, and more specifically, the minimum required capacity of each individual component in that system. It also establishes the method for distributing egress capacity to various egress paths where multiple means of egress are provided.

There are two methods established by this section for the determination of the minimum required width/capacity of the means of egress all along the various egress paths. These methods are typically referred to as “component” width and “calculated” width. The greater width or capacity required for each egress element based on component width and calculated width is to be applied in the design of the means of egress system. Component width, addressed in Section 1005.2, is specified throughout the code based on the specific means of egress component under review. As an example, the minimum required component width of a corridor is based on Table 1020.2. Calculated width, addressed in Section 1005.3 as required capacity, is determined based on the appropriate formula as established in Section 1005.3.1 for stairways and Section 1005.3.2 for egress components other than stairways. It is important to note again that the greater required width as established by component width and calculated width is to be provided. See Application Example 1005-1.

Section 1029 provides special means of egress requirements for those rooms, spaces, and areas used for assembly purposes. Where an assembly use contains seats, tables, displays, equipment, or similar elements, the requirements set forth in Section 1029 for aisles and aisle accessways are to be applied in addition to the general means of egress requirements of Chapter 10.

Application Example 1005-1

1005.2   Minimum width based on component.   Egress components all have a minimum width established by other provisions in the code. It should be noted that where the component width is the appropriate method for determining egress width, in many situations the required component widths may lessen along the egress path. For example, in an office building with an occupant load of 68 persons, a corridor required to be at least 44 inches (1,118 mm) in width by Table 1020.2 may lead to an exit door with a minimum clear width of 32 inches (813 mm) as regulated by Section 1010.1.1. In this example, the minimum component widths for the corridor and the exit door provide for greater widths than the capacity required by Section 1005.3.2.

1005.3   Required capacity based on occupant load.   The formula for means of egress capacity based on occupant load is very succinct. It states that the total required capacity of the means of egress shall not be less than that obtained by multiplying the total occupant load served by an egress component by the appropriate factor as set forth in Section 1005.3.1 or 1005.3.2, as applicable. It should be noted that the calculation of egress capacity for aisles and aisle accessways in assembly occupancies is not regulated by this section, but rather is governed by Section 1029.6. Where an assembly space contains seats, tables, displays, equipment, or other fixtures or furnishings, it must comply with the means of egress provisions of Section 1029.

In designing the means of egress system, it is first necessary to determine the occupant load that must be accommodated through each individual portion of the system. The occupant load anticipated to be served by each individual component is the basis for sizing each component. The design occupant load is to be used when determining both the component width and the calculated width. Continuing to use a corridor as an example, Table 1020.2 requires a minimum component width of 44 inches (1,118 mm) where serving an occupant load of 50 or more, but only 36 inches (914 mm) where serving an occupant load less than 50. For calculated width (required capacity), multiplying the occupant load by the appropriate factor in Section 1005.3.1 or 1005.3.2 will result in the minimum required capacity in inches (mm) necessary to accommodate the occupant load. An example is shown in Application Example 1005-2.

Application Example 1005-2

It cannot be emphasized too strongly that when the code discusses width in terms of an egress system or component, it is referring to the clear, unobstructed, usable width afforded along the exit path by the individual components. Therefore, if it is determined, for example, that a means of egress must have a width of at least 3 feet (914 mm), it shall be arranged so that it is possible to pass a 36-inch-wide (914-mm) object through that egress path and each of its components. Unless the code specifically states that a projection is permitted into the required width by Section 1005.7, nothing may reduce the width of the component required to provide the necessary exit capacity.

Egress width in assembly spaces. As previously mentioned, where the provisions of Section 1029 are applicable for assembly uses, the egress width and capacity of aisles and aisle accessways shall be determined based on such provisions. The requirements of Section 1029 regulate all assembly spaces containing seats, tables, displays, equipment, or other material. Thus, it is typical that the egress capacity requirements of Section 1029.6 are to be followed rather than those of Section 1005.1. Section 1029.6 addresses egress capacity for assembly uses, based primarily on whether or not smoke-protected assembly seating is provided. A further discussion of this subject is provided in the analysis of Section 1029.

1005.3.1   Stairways.   This provision establishes the method for determining the required capacity of an egress stairway, based on the occupant load assigned to the stairway. As a basic requirement, the capacity of a stairway is based on the occupant load assigned to the stairway multiplied by 0.3 inches per occupant. Where the building is provided with both an automatic fire sprinkler system and an emergency voice/alarm communication system, a factor of 0.2 inches per occupant is to be used. The presence of these two fire-protection systems allows for a 33 percent reduction in the minimum required calculated egress capacity. Again, the minimum required component width must also be addressed. This reduction to 0.2 inches per occupant is not permitted in Group H and I-2 occupancies.

Provided the occupants are traveling in the same direction, there is no need to combine the loads from adjacent stories. The IBC assumes that in exiting multistory buildings there will be occupants feeding into the exit stairs at various stories. This approach recognizes that using the cumulative occupant load for vertical travel often results in stairway widths of significant size. The reduced sizes established by the floor-by-floor method may result in some increase in occupant evacuation time; however, the slower evacuation rate is deemed acceptable since the travel occurs within a fire-resistance-rated enclosure. This is in contrast to the methodology applied to horizontal travel where cumulative occupant loads must be addressed due to the fact that such travel is typically in unprotected portions of the exit access. The capacity factors are substantially higher for stairways than for horizontal egress components, primarily because the speed of exiting on a stair is substantially less than the speed of exiting on level or nearly level surfaces. On stairways there is a forced reduction in normal stride, as the length of stride on a stair must coincide with the stair’s run. A study of this difference shows that a stairway requires an increase in width of approximately 50 percent above that for horizontal travel in order to maintain equivalent flow rates.

At one time, building codes addressed a cascading effect when analyzing and determining the required width of stairs, but this concept is no longer applicable. The required width of a stair is calculated on a story-by-story application of the formula.

In the design of multistory buildings, it is quite common that different stories have different occupant loads. Thus, the occupant load calculated for each story must be considered. As a matter of fact, it is not uncommon for buildings to have assembly uses on the top story. As a consequence of that configuration, it is entirely possible that the top story of a building will have an occupant load greater than any other. Under such a condition, it will be necessary to calculate the required stairway capacity based only on the occupant load of the uppermost story. This required capacity must be maintained through the successive stories until it serves a greater occupant load from a lower story or until the occupants have reached the public way or ultimate safe place. Figure 1005-1 illustrates this requirement.

Figure 1005-1   Width of exits—multistory buildings.

It should be noted that the same concept of determining stairway width that is discussed above applies where building occupants exit upward through the stairway. This is the situation in buildings with basements and sub-basements. Occupants of those below-grade floors must exit up the stairway, onto the landing on the ground floor, and then out through the exterior exit door from that landing. The largest capacity calculated from any floor level will be the controlling factor of the exit at ground level, as well as the exit doorway from the stairway. Of course, it is possible that occupants on the ground floor will exit through an enclosure of an interior exit stairway. If so, the required capacity determined based on that condition may govern. However, the ground floor usually has adequate width of exits independent of any paths through the stairway enclosures. Thus, the occupant load of the ground floor is usually not an issue in the determination of the exterior exit doorway capacity from the stairway enclosure. In any case, the occupant load of the ground floor would not be added to any occupant load of floors above for determining egress capacity from the building. Where upper and lower floors converge at an intermediate level, see the discussion of Section 1005.6 on egress convergence.

1005.3.2   Other egress components.   A means of egress capacity factor of 0.2 inches per occupant applies to those egress components other than stairways, such as ramps, aisles, and corridors. The factor may be reduced in all occupancies other than Groups H and I-2, provided the building is fully sprinklered and provided with an emergency voice/alarm communication system. Where both of these fire-protection features are provided, the capacity factor may be reduced to 0.15 inches per occupant.

1005.4   Continuity.   As stated earlier, it is the width of the most restrictive component that establishes the capacity of the overall exit system. To ensure that a design does not reduce the capacity at some point throughout the remainder of the egress system, this section stipulates that the width and capacity may not be reduced and that the design must accommodate any accumulation of occupants along the path. Therefore, once the required width or capacity is determined for any story (in fact, from any room or other space), that required width or capacity must be maintained until the occupants have reached the public way or ultimate safe place. It is important to remember that because different factors are used to determine the requirements for stairways than for all other components, it is really the required capacity, not the minimum width, of the egress system that is not permitted to be reduced. An aisle, door, corridor, exit passageway, or other horizontal egress component located at the bottom of any stairway may generally be reduced in capacity from what is required for the stairway. See Application Example 1005-3. This is simply due to the capacity factor of the stairway being greater than the factor for other egress elements. It must again be mentioned that only the required width or capacity needs to be maintained. The actual width of the means of egress may be reduced throughout the travel path as long as the required width is provided. A common application of this concept is shown in Figure 1005-2.

1005.5   Distribution of minimum width and required capacity.   When the required egress capacity of the system has been determined by the use of one of the formulas, and the required number of exit access doorways or exits has been determined in accordance with the provisions of Section 1006, the required egress capacity can be divided among the number of required means of egress. In fact, where additional complying means of egress are provided above the number required by the code, they too can be used for distribution purposes. The manner of distribution shall be such that the loss of any one means of egress will not reduce the available capacity to less than 50 percent of that required. Thus, after the loss of one means of egress, at least one-half of the required capacity must be available. See Application Example 1005-4. It is the intent of this section that there be reasonable distribution of the egress capacity necessary to serve a given occupant load.

Application Example 1005-3

Application Example 1005-4

The primary reason for requiring multiple egress paths is the fact that in a fire or other emergency, it could be possible that at least one of the routes will be unavailable or blocked by fire. If the egress capacity was concentrated at one exit point, it could very easily be that path that affords the greatest portion of the egress capacity that would be lost. The resulting limitation on the occupants’ ability to exit a building or portion thereof is simply unacceptable. In addition, the presence of two or more means of egress allows for a distribution of occupants, which should provide for more efficient and orderly egress under emergency conditions. A third benefit of egress distribution is the potential reduction in the distance occupants must travel to reach an exit or exit access doorway.

1005.6   Egress convergence.   This section directly addresses those situations where occupants from floors above and below converge at an intermediate level, rather than traveling in the same direction, as discussed in Section 1005.3.1. The code states that the proper approach for this condition would be to add the occupant loads together—a method that is also used when converging aisles or merging corridors. In these cases, it can be assumed that the occupants arrive at the same point at the same time and, therefore, the capacity of the system must accommodate the sum of these converging floors. See Figure 1005-3. Although the code does not specify the approach to be taken where there are multiple floors both above and below the intermediate level of discharge, it is anticipated that the same methodology of convergence would be applied. For example, the occupant load assigned from a second-level basement would be added to the occupant load assigned from the third floor, resulting in a congregate occupant load converging at the discharge level. The minimum required egress capacity would be based on the highest of the occupant loads that have been established.

Figure 1005-3   Egress convergence.

1005.7   Encroachment.   Where doors open into the path of exit travel, they create obstructions that may slow or block egress. Therefore, the code limits the encroachment of doors into the required exit width. A door opening into a path of egress travel may not, during the course of its swing, reduce the width of the exit path by more than one-half of its required width. When fully open, the door may not project into the required width by more than 7 inches (178 mm). It is important to recognize that the provisions are based on the exitway’s required width, not its actual width.

Again, as discussed in connection with Section 1010.1.6 for doors swinging over a stairway landing, it might be better to think of the permitted obstruction of a door during the course of its swing from a positive viewpoint. So stated, each door, when swinging into an egress path such as an aisle or a corridor, must leave unobstructed at least one-half of the required width of the path of travel during the entire course of its swing. At least one-half of the required width must always be available for use by the building occupants. When the door is in its fully open position, the required egress width, minus 7 inches (178 mm), must be available. See Figure 1005-4.

Figure 1005-4   Egress obstruction due to door swing.

In applying the requirements for projections, the code imposes these limitations on a door-by-door basis. It is desirable that doors be arranged so as not to have two doors directly opposing each other on opposite sides of the exit path. Better design would avoid this arrangement. The intent of the code is that at least one-half of the required width of the exitway be available for use by the building occupant as illustrated in Figure 1005-5. The restrictions on door swing do not apply to doors within dwelling units and sleeping units of Groups R-2 and R-3.

Figure 1005-5   Doors swinging into egress path.

Where nonstructural projections other than doors, such as trim and similar decorative features, extend into the required width of a means of egress component, the limit on their projection into the required width of egress components is 1½ inches (38 mm) unless such projection is specifically prohibited by the code. In reviewing the provisions for aisles in Section 1018.1, corridors in Section 1020.3, and exit passageways in Section 1024.2, the encroachments established in this section are specifically permitted. Handrail projections are also permitted provided such projections do not extend beyond the limitations established in Section 1014.8. Of specific note is a reference to Section 407.4.3 regarding permissible projections into the required width of nursing home corridors.

Section 1006 Number of Exits and Exit Access Doorways

For the purposes of determining the minimum number of means of egress required to serve a building’s occupants, it is important to note that the code first looks at exiting from each individual room, space, or area within the building. The means of egress is then regulated for each story and any occupied roof.

1006.2.1   Egress based on occupant load and common path of egress travel distance.   It would seem obvious that every occupied portion of a building must be provided with access to at least one exit or exit access doorway. It is assumed that if buildings are occupied, then the occupants obviously have a method of entering the various building spaces. Therefore, that same entrance is available to serve as the means of egress. Under many conditions, however, the use of the entrance as the only egress point is insufficient. The basic reason for requiring at least two means of egress is that in a fire or other emergency, it is very possible that the entry door will be obstructed by the fire and, therefore, not be usable for egress purposes. A second exit or exit access doorway can provide an alternative route of travel for occupants of the room or area. However, it is often unreasonable to require multiple egress paths from small spaces or areas with limited occupant loads. It is also seldom beneficial because of the relatively close proximity in which such exits or exit access doorways must be located. Therefore, the code does not require a secondary egress location from all rooms, areas, or spaces where in compliance with Table 1006.2.1.

The IBC establishes two basic criteria for providing adequate egress for occupants from any space within the building. First, at least two exits or exit access doorways must be provided when the occupant load of the space exceeds the values set forth in Table 1006.2.1. Second, two or more egress doorways are required when the common path of egress travel exceeds the limitations also established in Table 1006.2.1. Only where both the design occupant load of the room, space, or mezzanine and the common path of egress travel distance set forth in Table 1006.2.1 are not exceeded is it permissible to have a single means of egress. See Application Examples 1006-1 and 1006-2.

As seen in Table 1006.2.1, the allowance for a single exit or exit access doorway from a space varies based on the occupancy designation of the space. The variations are caused by conditions associated with the specific uses that occur within the room or area. Factors that contribute to the differences in occupant load include the concentration of occupants, occupant mobility, and the presence of hazardous materials. There is a specific exception that allows a single means of egress from individual dwelling units within and from Group R-2 and R-3 occupancies in fully sprinklered buildings for occupant loads of 20 or less. An additional exception references the provisions of Section 407.4.3 for Group I-2 care suites.

In addition to the occupant load limitations imposed by Table 1006.2.1 for single exit rooms and spaces, the common path of egress travel distance is also strictly regulated. The definition of a common path of egress travel is found in Section 202. Described as “that portion of exit access travel distance from the most remote point within a story to that point where the occupants have separate access to two exits or exit access doorways,” a common path of egress travel is that portion of the exit system where no egress options are available to the occupant, and only ends once separate access is available to at least two exitways. The length of the common path is measured from the most remote point of a room or area to the nearest location where multiple exit paths to separate exits are available. See Figures 1006-1 and 1006-2.

Figure 1006-1   Common path of egress travel.

Figure 1006-2   Merging paths of travel.

Application Example 1006-1

Application Example 1006-2

As a general rule, the maximum length of a common path of egress travel is 75 feet (22,860 mm), as shown in Table 1006.2.1. Because of unique risks potentially encountered in a high-hazard occupancy, the common path of travel is limited to 25 feet (7,620 mm) in Groups H-1, H-2, and H-3. In certain occupancies and under specific conditions set forth in the table, an increase in the common path of travel to a distance of 100 feet (30,480 mm) or 125 feet (38,100 mm) is permitted. The method of measurement of the common path of egress travel should be consistent with that for measuring exit access travel distance as regulated in Section 1017. See the discussion of Section 1017.2 for further guidance. The most obvious example of a “common path” condition is a room with a single exit or exit access doorway. Although there are numerous paths that may lead to the doorway, eventually they all end up at the same point. Where two or more complying exits or exit access doorways are provided, common path conditions do not exist.

1006.2.2.1   Boiler, incinerator, and furnace rooms.   Depending on the capacity of the fuel-fired equipment located in a large boiler room or similar area, it may be necessary to provide a secondary egress doorway because of the potential hazards. At least two exit access doorways are required where the room exceeds 500 square feet (46 m²) and any single piece of fuel-fired equipment such as a furnace or boiler exceeds 400,000 Btu (422,000 KJ) input capacity. The requirement is based on the size of a single piece of equipment, not the aggregate total of all fuel-fired equipment in the room. Access to one of the two exit access doorways may be accomplished through the use of a ladder or an alternating stair device. As with other multiple-exit situations, the two doorways must be adequately separated, in this case by a horizontal distance no less than one-half the maximum overall diagonal.

1006.2.2.2   Refrigeration machinery rooms.   The International Mechanical Code ® (IMC®) mandates when refrigeration systems must be contained in a refrigeration machinery room. It can be based on the type of refrigerant, the amount of refrigerant, the type of equipment, or other factors. Once a refrigeration machinery room is required by the IMC, the IBC provides the exiting criteria. Where larger than 1,000 square feet (92.9 m²), the room must have at least two exit access doorways, accessed and separated in the same manner as described for boiler and furnace rooms. Egress doors from the room must be tight-fitting, self-closing, and swing in the direction of travel. Travel distance is also restricted to 150 feet (45,720 mm). It is evident that the presence of multiple exitways and a more limiting travel distance are necessary in order to address the hazards associated with areas containing refrigerants.

1006.2.2.3   Refrigerated rooms or spaces.   Considered a bit less of a concern than refrigerated machinery rooms, rooms or spaces that are refrigerated still pose somewhat of a hazard because of the refrigerants used in the system. The requirements for such rooms or spaces differ little from those for refrigeration machinery rooms, except that the less restrictive general travel distances apply if the room or space is sprinklered and egress is permitted through adjoining refrigerated rooms.

1006.3   Egress from stories or occupied roofs.   This section is a continuation of the provisions established in Section 1006.2 relating to the minimum number of exits or access to exits required throughout the means of egress system. Section 1006.2 is to be applied within rooms or spaces within a story and identifies those conditions under which one, two, three, and four means of egress are required from such rooms or spaces. Section 1006.3 regulates the minimum number of exits or access to exits required from each story of a building. The Section 1006.3.2 allowances for a single exit, as well as the requirements for multiple exits, are established for each individual story, as well as for any occupied roof.

As few as one exit may be permitted, based on occupancy classification, occupant load, and story location within the building. On the other hand, up to four exits may be required based primarily on the occupant load of the story. In all cases, once a minimum required number of exits or exit access stairways has been established by the code, that number cannot be reduced. It is possible to use a combination of interior/exterior exit stairways and exit access stairways for means of egress purposes. It is permissible that the means of egress from the second story of a building consist of all exit access stairways as regulated by Section 1019. However, above the second story, at least some portion of the required egress must be provided through the use of interior exit stairways and/or exterior exit stairways, as described in Sections 1023 and 1027, respectively.

Where two means of egress are required from a third story above grade plane or higher, this section only requires one interior exit stairway or ramp, or exterior stairway or ramp. The other required means of egress is permitted to be an exit access stairway complying with Section 1019. Vertical travel on an exit access stairway must be considered in the evaluation of travel distance and such travel is only available to a single adjacent story. The use of an exit access stairway as a required means of egress component is limited to one story of travel, at which point the occupants must use an interior exit stairway or other exit element. See the example in Figure 1006-3.

Figure 1006-3   Access to exits at adjacent levels.

1006.3.1   Egress based on occupant load.   As established in Table 1006.3.1, every story shall be provided with two exits, or access to at least two exits. This requirement is also applicable to occupied roofs. A single means of egress is only permitted under the conditions identified in Section 1006.3.2. Table 1006.3.1 indicates that, based solely on occupant load, three, or even four, exits may be required. Any story of a building that has an occupant load in excess of 500, up to and including 1,000, shall be provided with three exits, or access to at least three exits. Any story having an occupant load in excess of 1,000 must be provided with four exits, or access to not less than four exits. Under no circumstances does the IBC require more than four exits for any building or portion thereof based on the number of persons present. It must be noted, however, that additional exits will sometimes be required to satisfy the other egress requirements of Chapter 10. An additional interior exit stairway may also be required in high-rise buildings over 420 feet (128 m) in height per Section 403.5.2.

1006.3.2   Single exits.   As a general requirement expressed in Table 1006.3.1, every story and occupied roof shall be provided with two exits, or access to at least two exits. However, a single means of egress is permitted where the story or occupied roof is within the limits of Table 1006.3.2(1) or Table 1006.3.2(2) as permitted by Exception 1, or where one of the other four exceptions to this section specifically permits a single exit.

Although it is desirable that a minimum of two means of egress be provided to building occupants in order to provide for a more reliable and efficient evacuation process, the code recognizes that there are instances where the life-safety risk is so minimal that it is reasonable to permit a single means of egress. Under limited conditions, this allowance extends from a single-level basement to a three-story-above-grade-plane condition. Tables 1006.3.2(1) and 1006.3.2(2) identify those stories where a single exit, or access to a single exit, is permitted. The tables are based on varying criteria, including occupancy classification, number of stories above the grade plane, occupant load, number of dwelling units, and common path of egress travel distance. Examples illustrating the use of these tables are shown in Figure 1006-4. It should be noted that special consideration is given in Footnote b of Table 1006.3.2(2) for certain Group B, F, and S occupancies. Exception 4 recognizes that all Group R-3 and R-4 occupancies may have a single exit, while Exception 2 addresses stories at the exit discharge level complying with Section 1006.2.1 for spaces requiring only one means of egress.

Figure 1006-4   Stories with one exit.

Only one exit or access to a single exit is required from a story where permitted by Table 1006.3.2(1) or Table 1006.3.2(2), regardless of the number of means of egress required from other stories in the building. For example, a Group B occupancy on the second story of a multistory building is only required to have one exit, or access to one exit, from the story, provided its occupant load does not exceed 29 and the maximum common path of egress travel distance to an exit does not exceed 75 feet. The number of occupants and travel distances on the other stories do not affect the determination of the second story as a single-exit story. See Application Example 1006-3. Where applicable, other stories are also regulated independently as to the number of means of egress.

The two tables referenced by Exception 1 differ only in the occupancy classifications to which they are applicable. Table 1006.3.2(1) is only to be used for Group R-2 occupancies consisting of dwelling units, such as apartment buildings. The allowance for a single exit, or access to a single exit, is regulated based on the story’s relationship to grade plane, the number of dwelling units on the story, and the maximum common path of egress travel distance provided. Complying emergency escape and rescue openings must also be provided in all of the dwelling units. Table 1006.3.2(1) does not apply to dormitories, fraternity, sorority houses, and similar Group R-2 occupancies comprised of sleeping units. Table 1006.3.2(2) applies to all occupancies other than those specific Group R-2 occupancies addressed by Table 1006.3.2(1). A single means of egress from each story of such occupancies is regulated by the occupancy classification, number of occupants per story, maximum common path of egress travel distance, and the story’s relationship to grade plane.

1006.3.2.1   Mixed occupancies.   Where multiple tenants or occupancies are located on a specific story, they are to be regulated independently for single-exit determination. The provisions can be applied to specific portions of the story, rather than the story as a whole. As an example, the second story of a building houses two office tenants, each with its own independent means of egress. Each tenant would be permitted a single, but separate, means of egress provided each had an occupant load of less than 30 and a common path of egress travel distance not exceeding 75 feet. This portion-by-portion philosophy also applies to a mixed-occupancy condition, provided each of the individual occupancies does not exceed the limitations of Table 1006.3.2(2). See Figure 1006-5.

Figure 1006-5   Stories with one exit.

Application Example 1006-3

1006.3.2.2   Basements.   Also illustrated in Figure 1006-4 is a permitted condition for a basement where a single exit is permitted. Conditions of this section limit the basement to a single level below the first story. Both common path of egress travel distance and occupant load are also limited by Table 1006.3.2(1) or Table 1006.3.2(2) as applicable.

Section 1007 Exit and Exit Access Doorway Configuration

In addition to providing multiple means of egress, it is imperative that egress paths remain available and usable. To ensure that the required egress is sufficiently remote, the code imposes rather strict requirements relative to the location or arrangement of the different required exits or exit access doorways with respect to each other. The purpose here is to do all that is reasonably possible to ensure that if one means of egress should become obstructed, the others will remain available and will be usable by the building occupants. As a corollary, this approach assumes that because the remaining means of egress are still available, there will be sufficient time for the building occupants to use them to evacuate the building or the building space.

1007.1.1   Two exits or exit access doorways.   This remoteness rule in the IBC is sometimes referred to as the one-half diagonal rule. The one-half diagonal rule states that if two exits or exit access doorways are required, they shall be arranged and placed a distance apart equal to or greater than one-half of the maximum overall diagonal of the space, room, story, or building served. Such a minimum distance between the two means of egress, measured in a straight line, shall not be less than one-half of that maximum overall diagonal dimension. See Figure 1007-1 for examples of the application of this rule. It should be noted that, by definition, the term exit access doorway includes any point of egress where the occupant has a single access point that must be reached prior to continued travel to the egress door. See Figure 1007-2.

Figure 1007-1   Separation of exits or exit-access doorways.

Figure 1007-2   Egress separation.

The use of the one-half diagonal rule has been beneficial to code users for many years. It quantifies the code’s intent when the code requires that separate means of egress be remote. It does not leave the building official with a vague performance-type statement that can, in many instances, result in a situation where egress separation would be dictated more by the design or desired layout of the building rather than by a consideration for adequate and safe separation of the means of egress.

In applying the one-half diagonal rule to a building constructed around a central court with an egress system consisting of an open balcony that extends around the perimeter of the court, it is important to take the measurement of the diagonal from which the one-half diagonal dimension is derived at the proper locations. Refer to Figure 1007-3 for examples.

Figure 1007-3   Required egress separation.

Figure 1007-4 illustrates Exception 1 to the one-half diagonal rule for those buildings, such as core buildings, where the means of egress are sometimes arranged in rather close proximity. The code recognizes the benefits of such a floor arrangement and makes a specific exception in the event there is such a design. If the exits or exit access doorways are connected by a fire-resistance-rated corridor, the distance determined by one-half of the maximum overall diagonal of the space served may be measured along the shortest path of travel inside the corridor between the two exits. It is specific that the connecting corridor is to be of 1-hour fire-resistant construction.

Figure 1007-4   Core arrangement of interior exit stairways.

A second exception reduces the minimum length of the overall diagonal dimension between remote exits or exit access doorways in those buildings equipped throughout with automatic sprinkler systems. Because of the presence of sprinkler protection, the separation distance need only be one-third of the length of the overall diagonal dimension. The use of this exception results in a reduction of the required distance between exits or exit access doorways by 33⅓ percent. See Figure 1007-5.

Figure 1007-5   Exit separation—sprinklered building.

1007.1.1.1   Measurement point.   The code specifically indicates the manner in which the straight-line measurement should be taken. Three measurements methods are established to clearly indicate how to measure between doors, stairways, and ramps. Any point within the width of the exit or exit access doorway may be selected by the designer for measurement purposes. This will typically result in measuring between the far edge of one egress doorway opening and the far edge of the other egress doorway opening in order to allow the greatest design flexibility.

1007.1.2   Three or more exits or exit access doorways.   When more than two means of egress are required, the remoteness rule takes on more of a performance character. In such an instance, at least two of the required exits or exit access doorways shall be arranged to comply with the one-half diagonal rule (one-third in fully sprinklered buildings). The other means of egress must be arranged at a reasonable distance from the other egress points so that if any one of the required exits or exit access doorways becomes blocked by a fire or any other emergency, the others will be available. Obviously, this decision will require some very careful evaluation and judgment on the part of the building official. There may be a sufficient basis for applying that same rule when considering each possible pair of egress components in a multi-exit situation. The code is silent in this particular aspect, and proper code administration does require substantial, careful evaluation and judgment on the part of the building official in ensuring that the number of means of egress required is sufficiently remote so that it is not likely that the use of more than one access to exit will be lost in any fire incident. A similar evaluation should be done where more than two exit access stairways or ramps provide the required means of egress.

1007.1.3   Remoteness of exit access stairways or ramps.   Minimum separation distances between exit access stairways and ramps are required to be maintained for the entire length of travel on the stairway or ramp. See Figure 1007-6. This requirement prohibits stairway and ramp runs that meet the separation distance at the first riser or beginning of the slope from converging toward another stair or ramp such that the separation is reduced below the minimum distance as the occupant goes either up or down the stairway or ramp. It is reasonable to expect the egress separation distance to be maintained in order to ensure a fire cannot affect both of the egress paths, whether it is at the beginning of the stair or ramp or at any point until the egress travel is completed.

Figure 1007-6   Measurement points for exit access stairways.

Section 1008 Means of Egress Illumination

1008.2   Illumination required.   In order for the exit system to afford a safe path of travel and for the building occupant to be able to negotiate the system, it is necessary that the entire egress system be provided with a certain minimum amount of illumination. Without such lighting, it would be impossible for building occupants to identify and follow the appropriate path of travel. The lack of adequate illumination would also be the cause of various other concerns, such as an increase in evacuation time, a greater potential for injuries during the egress process, and most probably an increased level of panic to those individuals trying to exit the building. Therefore, the code requires that, except in a limited number of occupancies, the egress paths be illuminated throughout their entire length any time the building space served by the means of egress is occupied. The code intends that illumination be provided for those portions of the egress system that serve the parts of the building that are, in fact, occupied. Parts of the exiting system that would not be serving the occupants of the building need not, at that time, be illuminated. For obvious reasons, there are four exceptions that identify areas where continuous illumination during occupancy is not mandatory. Two exceptions address uses where sleeping is a common activity—dwelling units and sleeping units in Group R-1, R-2, and R-3 occupancies, and sleeping units in Group I occupancies. Another exception addresses utility structures designated as Group U, whereas a fourth exception exempts aisle accessways in Group A assembly uses.

It is mandated that the entire means of egress serving the occupants be illuminated. Therefore, the exit discharge—that portion of egress travel from the building to the public way—must also be provided with adequate illumination. Although there are often numerous light sources at a building’s exterior, such as lighting for landscaping, parking lots, city streets, and adjacent buildings, it is important that the illumination be effective and reliable for use under this provision. It should also be noted that the requirements of this section are simply for general illumination of the entire egress system, and are not the higher-level conditions for emergency lighting as mandated in Section 1008.3.

1008.2.1   Illumination level under normal power.   Such illumination must be capable of producing a light intensity of not less than 1 foot-candle (11 lux) at the walking surface throughout the entire path of travel through the system. One foot-candle (11 lux) of light on a surface is not a great deal of light. It is probably not sufficient light to enable a person to read. However, it is sufficient light to allow a person passing through the exit system to distinguish objects and to identify obstructions in the actual path of travel. The light cast by a full moon on a clear night might approximate the 1 foot-candle (11 lux) light level. When the amount of light intensity is in doubt, it may be necessary to measure it with a light meter.

An exception recognizes that such levels of illumination might interfere with presentations in such places as motion picture theaters and concert halls; therefore, the exception allows a reduction in such building uses to a level of not less than 0.2 foot-candle (2.15 lux). Such a reduced lighting level, however, is permitted only during a performance and would be brought up to the minimum 1 foot-candle (11 lux) level if a fire alarm system were activated. A second method permits the use of self-luminous marking of the steps, landings, and ramps in accordance with Section 1025.

1008.3   Emergency power for illumination.   Normally, the power for illumination of the egress path is provided by the premises’ wiring system. However, where the potential life-safety hazard is sufficiently great, it is considered inadequate to solely provide the illumination of the exit system by such a system. In these cases, it is necessary that emergency power—a completely separate source of power—automatically provide illumination of the exitways. In fundamental terms, separate sources of power are required in all occupancies in which two or more means of egress are required. Therefore, any space, area, room, corridor, exterior egress balcony, or other portion of the egress system requiring access to at least two exits or exit access doors is to be provided with emergency lighting. An example of this application is depicted in Figure 1008-1. Also included are exit stairways, both interior and exterior, and exterior landings at exit doors in buildings requiring a minimum of two means of egress. Several specific rooms and spaces, identified in Section 1008.3.3, must also be provided with emergency power for illumination purposes.

Figure 1008-1   Emergency power for egress illustration.

Where emergency power systems are required, they are to be supplied by storage batteries, unit equipment, or an on-site generator. It is the intent that this power source be automatically available even in the event of the total failure of the public utility system. Therefore, a separate, independent source is generally required. Installation of the emergency power system is regulated by referring to the requirements of NFPA 70.

The initial illumination provided by emergency power along the path of egress at floor level shall average at least 1 foot-candle (11 lux), with a minimum level of illumination required to be 0.1 foot-candle (1 lux). Illumination levels are permitted to decline over the required 90-minute duration of the emergency power source to an average of 0.6 foot-candle (6 lux) with a minimum at any point of 0.06 foot-candle (0.6 lux). Recognizing the variation in light levels throughout the exit path, only the average illumination level needs to be determined; however, an absolute minimum level of illumination must be attained. In no case shall the illumination uniformity ratio between the maximum light level and the minimum light level exceed 40 to 1.

Section 1009 Accessible Means of Egress

1009.1   Accessible means of egress required.   In addition to the access to buildings required by the provisions of Chapter 11, it is important that safe egress for physically disabled individuals is provided. Therefore, the code requires that accessible spaces be provided with accessible means of egress consisting of one or more of the following components as set forth in Section 1007.2:

1.   Accessible routes complying with Section 1104.

2.   Interior exit stairways complying with Sections 1009.3 and 1023.

3.   Exit access stairways complying with Sections 1009.3 and 1019.3 or 1019.4 (unless connecting levels in the same story).

4.   Exterior exit stairways complying with Sections 1009.3 and 1027 (where serving floor levels other than the level of exit discharge).

5.   Elevators complying with Section 1009.4.

6.   Platform lifts complying with Section 1009.5.

7.   Horizontal exits complying with Section 1026.

8.   Ramps complying with Section 1012.

9.   Areas of refuge complying with Section 1009.6.

10.   Exterior areas for assisted rescue complying with Section 1009.7 (where serving exits at the level of exit discharge).

At least one accessible means of egress must be provided from all accessible spaces. Where more than one means of egress is required from any accessible space, at least two accessible means of egress are required. An example to illustrate this provision is a large department store requiring multiple exits. Although the number of required exits from the store is addressed in Section 1006.3, only two accessible means of egress would be required from the accessible space. Therefore, the store might be required to provide three or more means of egress, but only two accessible means of egress need be provided.

Three exceptions reduce or eliminate the accessible means of egress requirements. Where a building is existing, it is not necessary to provide any accessible means of egress. In addition, only one accessible means of egress is required from accessible mezzanines, as well as from sloped-floor or stepped assembly spaces with limited travel to all wheelchair spaces.

1009.2   Continuity and components.   As previously mentioned in the discussion of Section 1009.1, the code recognizes various accessible elements as components of an accessible means of egress. The accessible egress travel is required to extend beyond the building itself to the public way, unless an alternative means of protection is provided. If the egress route from the building to the public way is not accessible, it is acceptable to provide a complying exterior area of assisted rescue rather than create an accessible exit discharge path. Addressed further in the discussion of Section 1009.7, the exterior area of assisted rescue performs in much the same manner as an area of refuge inside the building.

1009.2.1   Elevators required.   Unlike the general provision found in Section 1003.7 that specifically prohibits considering an elevator as an approved means of egress, this section requires an elevator for rescue purposes under certain conditions. In buildings where a required accessible floor is four or more stories above or below a level of exit discharge, ramps and stairs cannot adequately serve as egress for individuals with a mobility impairment. Therefore, at least one elevator must be provided as an accessible means of egress. The elevator is not required to conform with Section 1009.4 in sprinklered buildings on those floors provided with a conforming ramp or horizontal exit.

In the application of this provision, the second story of a typical building is considered the first story above the level of exit discharge. Accordingly, the building’s fifth story is typically viewed as four stories above the level of exit discharge. See the discussion of Section 202 for level of exit discharge and Figure 1009-1. Under such conditions, a minimum of one accessible means of egress must be a complying elevator.

Figure 1009-1   Elevator as accessible means of egress.

1009.3   Stairways.   Exit stairways are typically used as one or more of the required accessible means of egress in a multistory building. Increasing the width of stairs to 48 inches (1,219 mm) between the handrails allows for the minimum amount of space needed to assist persons with disabilities in the event of a building evacuation. The provisions for an area of refuge or, as specified in Exception 9, a horizontal exit address the increased time needed for egress. The last sentence of the section is intended to address exit access steps in assembly seating or split-level buildings where an individual awaiting assistance or rescue may be required to wait in the middle of a building and not be able to travel toward an exit. There is no intent to prohibit the use of exit access stairways as part of an accessible means of egress from mezzanines and balconies as established in Exception 1.

A number of other exceptions eliminate the general requirement for an area of refuge. Areas of refuge are not mandated at exit stairways serving open parking garages. In addition, areas of refuge are not mandated in Group R-2 occupancies and in smoke-protected assembly seating areas as regulated by Section 1029.6.2. Another two exceptions remove the requirement for at least 48 inches (1,219 mm) of clear width between handrails. The 48-inch (1,219-mm) width is not mandated in sprinklered buildings, nor is it required for stairways accessed from a horizontal exit. Exception 4 addresses exit access stairways, eliminating any area of refuge requirement where two-way communication is provided at elevator landings under the provisions of Section 1009.8.

The most commonly applied exception permits the omission of areas of refuge in buildings protected throughout by an automatic sprinkler system. The purpose of an area of refuge is to provide an area “where persons unable to use stairways can remain temporarily to await instructions or assistance during emergency evacuation.” Much of the reasoning in exempting fully sprinklered buildings from the requirement for areas of refuge comes from NISTIP 4770, a report issued by the National Institute of Standards and Technology (NIST) in 1992 titled Staging Areas for Persons with Mobility Impairments. The primary conclusion of the report was that the operation of a properly designed sprinkler system eliminates the life threat to all occupants regardless of their individual abilities and can provide superior protection for persons with disabilities as compared to staging areas. The ability of a properly designed and operational automatic sprinkler system to control a fire at its point of origin and to limit production of toxic products to a level that is not life threatening to all occupants of the building, including persons with disabilities, eliminates the need for areas of refuge.

1009.4   Elevators.   Although an elevator may be used as an accessible means of egress component in all multilevel facilities, it is only required as such in buildings regulated by Section 1009.2.1. Elevators used as accessible means of egress must comply with the operation and notification criteria of ASME A17.1, Section 2.27. In addition, standby power is required in order to maintain service during emergencies. The general requirement is that any elevator used as an accessible means of egress be accessed from an area of refuge or, as established in Exception 5, a horizontal exit. However, areas of refuge are not required in fully sprinklered buildings, open parking garages, smoke-protected assembly seating areas, and where elevators are not required to be protected by shaft enclosures. Additional information is provided in the discussion of Section 1009.3. In such cases, the elevator is still considered an accessible means of egress when in compliance with the other criteria of this section.

1009.5   Platform lifts.   Except in limited applications, a platform lift is specifically excluded as an acceptable element of a means of egress. The maintenance of the lift as well as the complexity and delay in using a platform lift are considered substantial obstacles in providing acceptable means of egress for persons in wheelchairs. Section 1109.8 specifically sets forth the few instances where platform lifts are permitted for access and, with the exception of Item 10, egress purposes. Where a complying platform lift is used as an accessible means of egress component, it must be provided with standby power, much in the same manner as an elevator used for the same purpose.

1009.6   Areas of refuge.   By definition, an area of refuge is an area “where persons unable to use stairways can remain temporarily to await instructions or assistance during emergency evacuation.” Unfortunately, the term temporary is not defined, so a number of provisions are applied to an area of refuge to increase the level of protection for anyone using it. These provisions include a size large enough to accommodate wheelchairs without reducing exit width, smoke barriers designed to minimize the intrusion of fire and smoke, two-way communications systems, and instructions on the use of the area under emergency conditions. The two-way communications system is intended to allow a user of the area of refuge to identify his or her location and needs to a central control point. Obviously, it is important that someone be available to answer the call for help when a two-way communications system is provided. The system shall have a timed automatic telephone dial-out capability to a monitoring location or 911 that can be used to notify the emergency services when the central control point is not constantly attended. Each area of refuge shall be identified by a sign with the international symbol of accessibility stating that it is an area of refuge.

1009.6.3   Size.   Each required area of refuge shall be sized to accommodate at least one wheelchair space not less than 30 inches by 48 inches (762 mm by 1,219 mm). Where the occupant load of the refuge area and the areas served by the refuge area exceeds 200, additional wheelchair spaces must be provided. Because wheelchair spaces are not permitted to reduce the required exit width and should be located so as to not interfere with access to and use of the fire department hose connections and valves, the designer needs to consider access to fire protection equipment and exit width when placing wheelchair spaces in the area of refuge.

1009.6.4   Separation.   The primary concern for individuals awaiting assistance in an area of refuge is the intrusion of smoke and toxic gases into the refuge area. Therefore, the code requires a physical separation between an area of refuge and the remainder of the building. The separation is to be a smoke barrier complying with the provisions of Section 709. The smoke barrier is not required where the area of refuge is located within an enclosure for an interior exit stairway due to the inherent protection provided by such an egress enclosure. It is also permissible to create an area of refuge through the use of a horizontal exit.

1009.6.5   Two-way communication.   Individuals awaiting assistance in an area of refuge must be provided with a communication means in order to contact a central control point. Where the central control point is not constantly attended, the area of refuge must be provided with a complying telephone with dial-out capability. Both audible and visible signals shall be provided. The requirements for such communication systems are established in Sections 1009.8.1 and 1009.8.2.

1009.7   Exterior area for assisted rescue.   Item 10 of Section 1009.2 identifies an exterior area for assisted rescue as an acceptable portion of an accessible means of egress provided it complies with this section. The primary use of an exterior area for assisted rescue is to provide an exterior refuge area for those occupants unable to complete their egress travel due to the lack of an exterior accessible route from the building to the public way. Where exterior steps or other inaccessible site elements are present between the building’s discharge level and the public way, it is permissible to use an exterior area for assisted rescue as an alternative to a fully accessible exterior path. Sized in accordance with Section 1009.6.3, the exterior area for assisted rescue must be separated from the interior of the building in a manner similar to that addressed for egress courts and exterior exit stairways. Where the exterior area for assisted rescue is located within 10 feet (3,048 mm) horizontally of the building’s interior, a minimum 1-hour fire-resistance-rated wall with any openings protected for at least ¾ hour shall be provided from the ground level to a point at least 10 feet (3,048 mm) above the floor level of the exterior area for assisted rescue. Such protection need only extend to the roof line if it is less than 10 feet (3,048 mm) vertically above the floor level of the exterior area for assisted rescue. See Figure 1009-2. The required extent of an exterior area for assisted rescue is not described in the code, requiring an individual evaluation where the size of the exterior area for assisted rescue becomes quite large. For an outdoor space to be considered an exterior refuge area, it must be at least 50-percent open so that toxic gases and smoke do not accumulate. Where an exterior stairway serves the exterior area for assisted rescue, an adequate distance between the handrails is mandated. In addition, complying signage is required per Section 1009.9, Item 2, to identify the exterior area as an appropriate refuge location.

Figure 1009-2   Exterior area for assisted rescue.

1009.8   Two-way communications.   Unless provided in areas of refuge in multistory buildings, two-way communications systems must be located at the elevator landing of each accessible floor level other than the level of exit discharge. The system is intended to offer a means of communication to disabled individuals who need assistance during an emergency situation. Such a system can be useful not only in the event of a fire but also in the case of a natural or technological disaster by providing emergency responders with the location of individuals who will require assistance in being safely evacuated from floor levels above or below the discharge level. See Figure 1009-3.

Figure 1009-3   Two-way communication system at elevator landing.

The first exception exempts the requirement for locating the communication systems at the elevator landings where the building is provided with complying areas of refuge. Since areas of refuge are required by Section 1009.6.5 to be equipped with two-way communication systems, there is limited need to provide such additional systems at the elevator landings. However, where multistory buildings are not provided with areas of refuge, such as is the case with most sprinklered buildings, the installation of communications systems at the elevator landings is important to those individuals unable to negotiate egress stairways during an emergency. As a result, most sprinklered and nonsprinklered multistory buildings must be provided with the means for two-way communications at all accessible floor levels other than the level of exit discharge. A second exemption applies to floor levels that use exit ramps as vertical accessible means of egress elements. Where complying ramps are available for independent evacuation, such as occurs in a sports arena, the two-way communications system is not required at the elevator landings. It should also be noted that multistory buildings without elevators, such as those identified in Section 1104.4, would not be regulated by this section. Thus, all multistory buildings, except those exempted by Exception 2 and those without elevators, are required to be provided with two-way communication systems unless the only elevators in the building are freight, service, or private residence elevators.

The arrangement and design of the two-way communication system are specified in Section 1009.8.1. In addition to the required locations specified in Section 1009.6.5 for areas of refuge or Section 1009.8 for elevator landings, a communication device is also required to be located in a high-rise building’s fire command center or at a central control point whose location is approved by the fire department. The term “central control point” is not a defined term. However, given the intent and function of the two-way communication system, a central control point is a location where an individual answers the call for assistance and either provides aid or requests aid for an impaired person. A central control point could be the lobby of a building constantly staffed by a security officer, a public safety answering point such as a 9-1-1 center, a central supervising station, or possibly a nurses’ station in a Group I occupancy. The key functions at the central control point are that an individual is always available to answer the call for assistance and can either provide assistance or is capable of requesting assistance. In addition, the communication system provides visual signals for the hearing impaired and audible signals to assist the vision impaired.

Guidance to the users of the two-way communication system is also specified. Operating instructions for the two-way communication system must be posted and the instructions are to include a means of identifying the physical location of the communication device. If a signal from a two-way communication system terminates to a public safety answering point, such as a fire department communication center, current 9-1-1 telephony technology only reports the address of the location of the emergency—it does not report a floor or area from the address reporting the emergency. The “identification of the location” posted adjacent to the communication system should ensure that most discrete location information can be provided to the central control point. This will aid emergency responders, especially in high-rise buildings or corporate campuses with multiple multistory structures.

1009.11   Instructions.   Instructions on the use of the area of refuge or exterior area for assisted rescue must be provided where applicable. The intent of the instructions is not only to provide directions on the use of the communication equipment, but also to alert the users as to other available means of egress.

Section 1010 Doors, Gates, and Turnstiles

1010.1   Doors.   This section applies to doors or doorways that occur at any location in the means of egress system. The provision found in Section 1022.2 should also be noted insofar as it will require that at least one exterior door that meets the size requirements of Section 1010.1.1 be provided from every building used for human occupancy. As doors pose a potential obstruction to free and clear egress, they are highly regulated.

Additional doors. The IBC establishes criteria for all egress doors, including those that are not required by Chapter 10. Such additional egress doors must comply with all the provisions of Section 1010.1 for exit doors. Where the doors are installed for egress purposes, whether or not required by the IBC, the building occupant would probably assume that they are a part of the means of egress system. Because the building occupant would then expect the door to provide a safe path from the space, it is imperative that such doors and doorways conform to all applicable code requirements of Section 1010. Two examples are shown in Figures 1010-1 and 1010-2.

Figure 1010-1   Additional door.

Figure 1010-2   Additional door.

Door identification. The primary gist of the provisions on door identification is that egress doors should be installed so that they are readily recognized as egress doors and are not confused with the surrounding construction or finish materials. It is important that they be easily discernible as doors provided for egress purposes. The corollary of this requirement is that exit doors should not be concealed. In other words, they should not be covered with drapes or decorations, nor should they be provided with mirrors or any other material or be arranged in a way that could confuse the building occupants seeking an exit.

1010.1.1   Size of doors.   Every door used for egress purposes must comply with the width and height provisions of this section. It specifies that every required means of egress door opening be of such a size as to provide a clear width of at least 32 inches (813 mm), as illustrated in Figure 1010-3, with a minimum door height of 80 inches (2,032 mm). Again, the code requires that the net dimension of clear width be provided by the exit component. Thus, when a swinging door is opened to an angle of 90 degrees (1.57 rad), it must provide a net unobstructed width of not less than 32 inches (813 mm) and permit the passage of a 32-inch-wide (813-mm) object, unless a projection into the required width is permitted by Section 1010.1.1.1. Where a pair of doors is installed without a mullion, only one of the two leaves is required to meet the 32-inch (813-mm) requirement. As a final requirement, a minimum 41½-inch (1,054-mm) means of egress doorway width to facilitate the movement of beds is mandated for those portions of Group I-2 occupancies where bed movement is likely to occur.

Figure 1010-3   Minimum clear width of egress door.

A number of reductions to the 32-inch (813-mm) door-width requirement are found in the exceptions to this section. In Group I-3 occupancies, door openings to resident sleeping units need only have a clear width of at least 28 inches (711 mm). Accessible door openings within Type B dwelling units are permitted a minimum clear width of 31¾ inches (806 mm).

In addition, minimum door-opening widths are totally unregulated in the following locations:

1.   Door openings in Group R-2 and R-3 occupancies that are not part of the required means of egress.

2.   Storage closet doors where the closet is less than 10 square feet (0.93 m²) in area.

3.   Door leaves in revolving doors that comply with Section 1008.1.4.1.

4.   In other than Group R-1, interior egress doors within a dwelling unit or sleeping unit not required to be an Accessible unit, Type A unit or Type B unit.

5.   Shower and sauna doors in Group R-1 dwelling units and sleeping units not required to be Accessible units.

Throughout the rest of the code, the intent in specifying means of egress dimensions is to provide only minimum width. This particular section is at variance with that general approach, insofar as it limits the maximum width of any single swinging door leaf in a required egress doorway. As shown in Figure 1010-4, no such leaf may exceed 48 inches (1,219 mm) in width. The reason for this is that doors often do not receive the maintenance necessary to ensure their continued proper operation. The issue being addressed is that door leaves should be reasonably limited in width because wide doors require substantially greater maintenance to ensure reasonable opening effort, and this maintenance is not often provided. The limitation on maximum door width does not apply to complying revolving doors, or to doors in Group R-2 or R-3 occupancies that are not a portion of the required means of egress. It is also not applicable to nonswinging doors, such as overhead doors. In addition, the limit of 48 inches (1,219 mm) is increased to 60 inches (1,524 mm) for doors to small walk-in freezers and coolers.

Figure 1010-4   Maximum door leaf size.

The required clear width of door openings shall be maintained up to a height of at least 34 inches (864 mm) above the floor or ground. Projections may then encroach up to 4 inches (102 mm) for a height between 34 inches (864 mm) and 80 inches (2,032 mm). See Figure 1010-5. The maximum 4-inch (102-mm) limitation is based partially on those accessibility provisions regarding protruding objects. Its application allows for the intrusion of panic hardware, or similar door-opening devices, into the required clear width. At a height of 80 inches (2,032 mm) or more above the walking surface, the projection is not regulated.

Figure 1010-5   Egress door width.

Although the general requirement for door height is a minimum of 80 inches (2,032 mm), the exceptions to Sections 1003.3.1 and 1010.1.1.1 permit door closers and stops to encroach into this clear height, provided a headroom clearance of at least 78 inches (1,981 mm) is maintained. Door openings at least 78 inches (1,981 mm) in height must be provided within a dwelling unit or sleeping unit. A minimum height of 76 inches (1,930 mm) is required for all exterior door openings in dwelling units other than the required exit door. Only Exception 5 is applicable to the height reduction at a required exit door; therefore, required means of egress door openings must have a minimum height of 80 inches (2,032 mm), 78 inches (1,980 mm) at closers and stops, in other than a dwelling or sleeping unit.

1010.1.2   Door swing.   This section requires that every egress door, with exceptions, be of the pivoted or side-hinged swinging type. In most instances, it is necessary that the egress door encountered be of a type that is familiar to the user and easily operated. Therefore, swinging doors are required under all but the following conditions:

1.   Private garages, office, factory and storage areas, and similar spaces where the occupant load of the area served by the doors does not exceed 10. Because of the limitation in occupant load and potential hazard, other types of egress doors are considered acceptable. A common application of this allowance is the use of overhead doors at self-storage facilities.

2.   Detention facilities classified as Group I-3 occupancies. The security necessary in this type of use calls for special types of doors.

3.   Critical care or intensive care patient room within suites of health-care facilities. In these areas, it is preferable to use sliding glass doors to allow for visual observation and the efficient movement of equipment.

4.   Within or serving an individual dwelling unit in Group R-2 and R-3 occupancies. Because of the limited occupant loads involved, and the familiarity of the occupants with the doors encountered, door types other than swinging doors are permitted.

5.   Revolving doors conforming with Section 1010.1.4.1, where installed in other than Group H occupancies. In other than hazardous occupancies, the use of revolving doors is acceptable subject to the special conditions as set forth in the code.

6.   Special purpose horizontal sliding, accordion, and folding door assemblies complying with Section 1010.1.4.3, where installed in other than Group H occupancies. Conditions for the use of such doors make them equivalent to other doors used in egress situations.

7.   Power-operated doors in compliance with Section 1010.1.4.2. Safeguards provided for power-operated doors create an acceptable level of safety.

8.   Bathroom doors within individual sleeping units of Group R-1 occupancies. It is often beneficial to use sliding pocket doors to provide access to hotel bathrooms, mostly due to the minimum 32-inch (813-mm) width requirement for doors in Group R-1 occupancies. Conflicts often occur between door swings and the required clearances for plumbing fixtures or clear floor space required at bathroom doors.

9.   The use of a typical horizontal sliding door that is operated manually, such as a “pocket” door or a sliding “patio” door, is deemed acceptable in those instances where the occupant load served by the door is very low.

In addition, any pivot or side-hinged egress door serving an area or room with an occupant load of 50 or more, or those serving any Group H occupancy, shall swing with the flow of egress travel. In 1942, 492 people died in the Cocoanut Grove fire in Boston. One of the significant contributing factors to that loss of life was the fact that the exterior exit doors swung inward. As a consequence, it was not possible to open the doors because of the press of the crowd attempting to exit the building. This incident was identified as the primary reason for changing building codes to require that, under certain circumstances, exit doors must swing in the direction of exit travel.

1010.1.3   Door opening force.   Interior side-swinging doors other than fire doors must have a maximum opening force of 5 pounds (22 N). For doors that are sliding or folding, the door latch shall release when subjected to a 15-pound (66-N) force. This limitation to a 15-pound (66-N) force level also applies to all exterior swinging doors and interior swinging fire doors. In order to set the door in motion, a maximum force of 30 pounds (132 N) is mandated. The door shall swing to a fully open position when subjected to a force not greater than 15 pounds (66 N). These forces are applied to the latch side of the door. Most doors are openable with forces less than these maximum limits. However, when in doubt, the actual force required can be easily measured by use of a spring scale.

1010.1.4   Special doors.   Based on the provisions in Section 1010.1.2, the code generally requires that doors in exiting systems be of the pivoted or side-hinged swinging type. In this section, four different types of doors are identified that may be used under very specific conditions.

1010.1.4.1   Revolving doors.   Revolving doors continue to be used at building entrances. Where once used primarily in cold climates, they are now being installed in all regions, primarily as an energy-conservation measure. The use of revolving doors is specifically permitted as an alternative to enclosed vestibules where such vestibules are required by International Energy Conservation Code (IECC) at the entrances to commercial buildings. Exception 5 of Section 1010.1.2 permits the installation and use of revolving doors in all occupancies other than Group H when complying with this section. However, it is not permissible to use revolving doors to supply more than 50 percent of the required egress capacity, nor be assigned a capacity greater than 50 persons. Where used, the door must be an approved revolving door and comply with the specific requirements listed.

All revolving doors must be in full compliance with BHMA A156.27. When revolving doors are installed, they must be of a type where the door leaves will breakout under opposing pressures providing at least 36 inches (914 mm) of aggregate width. Location of the door in relationship to the foot or top of stairs or escalators is regulated, as is the maximum number of revolutions per minute. At least one conforming exit door shall be located in close proximity to the revolving door. In such an arrangement, the adjacent swinging door can be used to satisfy exit capacity requirements. The maximum force levels required to collapse a revolving door vary based on whether or not the door is to be used as an egress component.

1010.1.4.2   Power-operated doors.   Power-operated sliding or swinging doors are often used at the main entry of a building, particularly in mercantile and business occupancies. The same doors are also typically an important aspect in the overall exiting system for the building. There are a number of different types of doors that use a power source to open a door or assist in the manual operation of the door. This may include doors with a photoelectric-actuated mechanism to open the door upon the approach of a person, or doors with power-assisted manual operation. Where such doors are used as a portion of the means of egress, they must be installed in accordance with this section. The main criterion concerns the capability of the door being opened manually in the event of a power failure. Essentially, doors shall have the capability of swinging, and they must be designed and installed to break away from any position in the opening and swing to the fully open position when an opening force not exceeding 50 pounds (222 N) is applied at the normal push-plate location. Power-operated swinging, sliding, and folding doors must comply with BHMA A156.10, whereas BHMA A156.19 applies to swinging doors that are power-assisted and low-energy power-operated.

1010.1.4.3   Special purpose horizontal sliding, accordion, or folding doors.   Used as smoke and/or fire separation elements, these doors are normally in a fully open position and hidden from view. Closing only under specific conditions, they typically are part of an elevator lobby or similar protected area. Eight provisions are identified in the IBC that regulate the use of such doors as a component of means of egress. Fundamental to the use of these special doors is that manual operation of the normally power-operated doors must be possible in the event of a power failure, and no special or complex effort or knowledge should be necessary to open the doors from either side.

1010.1.4.4   Security grilles.   Because of the concern of exit doors being obstructed or even completely unusable, the use of security grilles is strictly regulated. By their nature, security grilles are difficult to operate under emergency conditions. Used frequently at the main entrances to retail sales tenants in a covered mall building, such grilles are also permitted in other Group M occupancies as well as Groups B, F, and S. Security grilles, either horizontal sliding or vertical, are only permitted at the main entrance/exit. During periods of time when the space is occupied, including those times where occupied by employees only, the grilles must be openable from the inside without the use of a key or special knowledge. They must be secured in the fully open position during those times where the space is occupied by the general public. Where two or more means of egress are required from the space, a maximum of 50 percent of the exits or exit access doorways are to be equipped with security grilles.

1010.1.5   Floor elevation.   The purpose of this section is to avoid any surprises to the person passing through a door opening, such as a change in floor level. Therefore, it is necessary that a floor or landing be provided on each side of a doorway. It is further intended that such a floor or landing should be at the same elevation on both sides of the door. A variation up to ½ inch (12.7 mm) is permitted because of differences in finish materials. See Figure 1010-6. Landings are required to be level, except exterior landings may have a slope of not more than ¼ inch per foot (6.4 mm per m) for drainage purposes.

Figure 1010-6   Floor elevation.

Exceptions for individual dwelling units of Group R-2 and R-3 occupancies. An allowance is provided for individual dwelling units where it is permissible to open a door at the top step of an interior flight of stairs, provided the door does not swing out over the top step. The reason for permitting this type of arrangement in dwelling units is that as a building occupant approaches such a door from the nonstairway side, he or she must back away from the door in order to open it. This creates the need for a minimum landing to be traversed before the occupant can proceed to step down onto the stairs. In this situation, with minimal occupant load and familiarity with the unusual condition, the opening may occur at the top of the stairs, but the door must swing toward the person descending the stairs. In an ascending situation, the stair user should have little difficulty in opening the door while standing on the stair treads, insofar as the door swings in the direction of travel. See Figure 1010-7. Also, in such occupancies it is permissible when screen doors or storm doors are installed, especially on the same jamb as the egress door, to swing them over stairs or landings.

Figure 1010-7   Floor level at doors.

In a Type B dwelling unit as provided in Chapter 11, a maximum drop-off of 4 inches (102 mm) is permitted between the floor level of the interior of the unit down to an exterior deck, patio, or balcony. This limited elevation change is consistent with the level of accessibility provided for travel throughout a Type B dwelling unit.

Exception for exterior doors. Reference is made to the first exception of Section 1003.5 regarding exterior doors in Group F, H, R-2, R-3, S, and U occupancies. Where such exterior doors are not required to be accessible, a single step having a maximum riser height of 7 inches (178 mm) is permitted. The reference to Section 1022.2 is extraneous information and it is not applicable in regard to the exception.

1010.1.6   Landings at doors.   This section contains the dimensional criteria for landings. It deals only with those landings where there is a door installed in conjunction with the landing. Landings at stairways and ramps are regulated by Sections 1011.6 and 1012.6, respectively.

Required width of landings. The minimum required width of a landing is determined by the width of the stairway or the width of the doorway it serves. Figure 1010-8 depicts these relationships. The requirement is that the minimum width of the landing be at least equal to the width of the stair or the width of the door, whichever is greater. The code is concerned that doors opening onto landings should not obstruct the path of travel on the landing. In this regard, the code establishes two limitations. The first states that when doors open onto landings, they shall not project into the required dimension of the landing by more than 7 inches (178 mm) when the door is in the fully open position. Second, whenever the landing serves an occupant load of 50 or more, doors may not reduce the dimension of the landing to less than one-half its required width during the course of their swing. Stated from the positive direction, it requires that doors swinging over landings must leave at least one-half of the required width of the landing unobstructed. Although the obstruction of one-half of the required width of the landing might seem excessive, it must be remembered that when the door is creating such an obstruction, it is in a position where it is free to swing and the obstruction is not fixed in place. These requirements are illustrated in Figure 1010-9.

Figure 1010-8   Width of landing at doors.

Figure 1010-9   Doors at landings.

Required length of landings. In addition to the width requirements, landings must generally have a length of at least 44 inches (1,118 mm) measured in the direction of travel. Where the landing serves Group R-3 and U occupancies, as well as landings within individual units of Group R-2, the length need only be 36 inches (914 mm). These code requirements are illustrated in Figure 1010-10.

Figure 1010-10 Length of landings at doors.

It should be noted that these minimum dimensions for landings in both width and length will be modified by the provisions in Chapter 11 where the door or doorway is a portion of the accessible route of travel.

1010.1.7   Thresholds.   Raised thresholds make using doors more difficult for people with disabilities. In addition, thresholds with abrupt level changes present a tripping hazard. As a general rule, raised thresholds should be eliminated wherever possible. Where thresholds are provided at doorways, it is necessary to limit their height to provide easy access through the doorway. Changes in floor level and raised thresholds are limited to ½ inch (12.7 mm) in height above the finished floor or landing. Where raised thresholds or changes in floor level exceed ¼ inch (6.4 mm), the transition shall be achieved with a beveled slope of 1 unit vertical to 2 units horizontal (1:2) or flatter. See Figures 1010-11 and 1010-12. For a sliding door serving a dwelling unit, a maximum ¾-inch (19.1 mm) threshold is permitted. The threshold height at exterior doors may be increased to a maximum height of 7¾ inches (197 mm) in Group R-2 and R-3 occupancies, but only where such doors are not a required means of egress door, are not on an accessible route, and are not part of an Accessible unit, Type A unit or Type B unit.

Figure 1010-11 Threshold height.

Figure 1010-12 Threshold height.

1010.1.8   Door arrangement.   Adequate space must be provided between doors in a series to allow for ease of movement through the doorways. In other than dwelling units not considered Type A units, a minimum clear floor space of at least 48 inches (1,219 mm) in length is sized for a wheelchair user to negotiate through the door arrangement. Where a door swings into the floor space, the clear length shall be increased by the width of the door. As shown in Figure 1010-13, doors in a series must swing in the same direction or swing away from the floor space between the doors.

Figure 1010-13 Two doors in series.

1010.1.9   Door operations.   This section, along with Section 1010.1.2, is particularly focused on the concept of ensuring that everything in the path of travel through the exit system, particularly doors, shall be under the control of and operable by the person seeking egress. Therefore, as a general statement, this section states that all doors in the egress system are required to be operable from the side from which egress is sought, without the need of a key or any special knowledge or special effort. If a key or special knowledge or effort is required, in all probability the door could not be readily openable by many building occupants. Such devices as combination locks are also prohibited on doors in exiting systems. Essentially, the code intends that the hardware installed be of a type familiar to most users—something that is readily recognizable under any condition of visibility, including darkness, and under conditions of fire or any other emergency.

In addition, the hardware must be readily operable. At times, one will encounter a different type of device such as a thumb turn. The building official must determine if this special type of operating device is acceptable. In many instances, it will be necessary to ensure that the building occupant can, in fact, grip the operating device and operate it. Some thumb turns are so small that they are quite difficult to operate, while others may require multiple twisting operations to achieve unlocking.

Another consideration that needs to be remembered in evaluating the acceptability of operating hardware is the fact that this hardware is going to be in place and in use over a substantial period of time. Unfortunately, doors and their operating hardware do not always get the constant maintenance that they should to keep them in operating order. It is imperative, in accordance with Section 1001.3, that the operation of doors in the egress system be maintained continuously in compliance with this section.

1010.1.9.1   Hardware.   Where a door is required to be accessible under the provisions of Chapter 11, additional criteria come into play. It is important that all door hardware intended to be encountered by the door user be of a type that does not require tight grasping, pinching, or twisting of the wrist for operational purposes. Individuals with limited hand dexterity must be able to operate the unlatching or unlocking device without any special effort.

1010.1.9.2   Hardware height.   The proper height of the operating hardware on an egress door is critical to ensure that the door user can easily reach and operate the unlatching or opening device. Therefore, operating devices such as handles, pulls, latches, and locks are to be installed at no less than 34 inches (864 mm) and no more than 48 inches (1,219 mm) above the finished floor. These limitations are not to be imposed on locks installed strictly for security reasons. An example might be a locking device installed on the bottom rail of an entrance/egress door of a convenience store or similar retail tenant.

1010.1.9.3   Locks and latches.   In regard to locking and latching door hardware, the IBC allows five significant exceptions to the general provision. In allowing these exceptions, it permits certain locking conditions that would appear to conflict with the basic requirement. However, in allowing these exceptions, the code often imposes certain compensating safeguards when the exit doors are to be locked or are provided with noncomplying hardware. It is the intent of the code that if the conditions are satisfied, the arrangement then essentially affords an equivalent level of safety as would be provided if the door were, in fact, readily openable at all times without the use of a key or any special knowledge or special effort.

1.   This exception for locking hardware primarily concerns Group I-3 occupancies such as prisons, jails, correctional facilities, reformatories, and similar uses, where individuals are restrained or secured. By their nature, it is necessary that the occupants in these facilities be limited in their movement. Therefore, the IBC allows alternative locks or safety devices when it is necessary to forcibly restrain the personal liberties of the inmates or patients.

Where a portion of a building is used for the restraint or security of five or fewer individuals, it is not considered a Group I-3 occupancy. Rather, it is anticipated that the secured area would simply be classified the same as the occupancy to which it is accessory. For example, up to five individuals could be restricted in an area such as a merchandise viewing room for customers in a jewelry store. In such situations, the allowance provided by Item 1 would be applicable for the egress door from the viewing room. A lock or latch that would prevent the expected unlocking or unlatching operation of the egress door would be acceptable. Thus, it is not necessary that the room or space be classified as a Group I-3 occupancy in order to apply this provision.

2.   The provisions of this exception apply to the main door or doors in Group A (having an occupant load of 300 or less), B, F, M, and S occupancies, and in all places of religious worship. It permits the main entrance/exit doors of buildings and spaces in buildings to be equipped with a key-operated locking device if several conditions are satisfied. In the occupancies listed, it is reasonable to assume that if the building or space is occupied, the main entrance/exit will, in all probability, be unlocked. The first condition states that the locking device be readily distinguishable as locked. The use of an indicator integral to the locking device may assist in determining when an unsafe condition is present. A second condition requires that there be a sign that is readily visible, permanently maintained, and located on or adjacent to the door. This sign is required to read THIS DOOR TO REMAIN UNLOCKED WHEN THIS SPACE IS OCCUPIED. The letters must be at least 1 inch (25 mm) in height and placed on a contrasting background. Both of these requirements are for legibility. Although the language of the sign appears to apply without exception, there will be obvious situations where it should not be taken literally. For example, where an employee is working after hours and may be the lone occupant in the building or space, it is not the intent that the main doors remain in an unlocked position.

Obviously, the sign or the presence of the sign is not going to ensure that the door is unlocked. However, it does advise the occupant that whenever the space is occupied, the law does require, in the interest of reasonable fire safety, that the door be unlocked. In the event the door is not unlocked, the occupant is advised that his or her life may be at risk. The occupant should seek to alleviate that situation. The limitation imposed by this provision is typically applied only when the public is involved. For example, it is not reasonable to assume that the subject door be unlocked during a time period the occupancy is limited to a janitor or other personnel. Note that the use of this exception may be revoked by the building official for due cause.

3.   Where egress doors are used in pairs, it is anticipated that each leaf in the pair of doors should be provided with its own operating hardware. This exception permits a special arrangement, however, when the pair of doors is equipped with automatic flush bolts that are designed so that the act of releasing one of the leaves of the pair releases both leaves. It is critical that the door leaf be provided with the automatic flush bolts and have no door handle or other surface-mounted hardware. To ensure the immediate and reliable operation of the pair of doors, the unlatching of either leaf in the pair must be accomplished by not more than one operation.

4.   The fourth exception refers to exit doors from individual dwelling or sleeping units of Group R occupancies. The general requirement of Section 1010.1.9.5 essentially prohibits the use of dead bolts or other security devices that would be installed in addition to the complying door hardware, as such an arrangement would require multiple operations to unlatch the door. This exception does permit, however, the use of a dead bolt, a security chain, or a night latch when the occupant load is 10 or less, on the condition that the device be openable from the inside without the use of a key or any special tool. It follows from the basic requirement of this section, however, that the device must not require any undue effort in order to unlatch the door and gain egress.

5.   The listed test procedures for a fire door include the disabling of the door operation mechanism. This exception clarifies that once the minimum elevated temperature has disabled the door’s unlatching mechanism, the resulting prevention of the door’s operation is acceptable.

1010.1.9.4   Bolt locks.   This section specifically prohibits the use of manually operated flush bolts or surface bolts insofar as these clearly do not conform with the intent of Section 1010.1.9. The use of such latching and/or locking hardware on means of egress doors is typically prohibited due to the inability of users to quickly identify and operate such devices under emergency conditions. Exception 1 permits the use of these types of locking devices on doors in individual dwelling units and sleeping units, provided the doors are not required for egress purposes. The second exception recognizes that in certain instances, doorway widths are dictated by the need to pass equipment through the openings. As a consequence, doorways, such as those to a storage room or equipment room, are frequently larger than would be required for exiting purposes alone. Therefore, where that is the case for a normally unoccupied space, manually operated bolts may be used on the inactive leaf. As the space is not normally occupied, this exception presents no significant hazard to life safety. The other side of this coin, however, is that any door leaf that is part of the required egress width must comply with all the requirements that apply to exit doors.

Pairs of doors are often desired in commercial occupancies to allow for the movement of furnishings, equipment, and machinery. Automatic flush bolts and removable center posts can be easily damaged and difficult to maintain in areas of frequent door usage. Exceptions 3 and 4, applicable to Group B, F, and S occupancies, address building functionality while maintaining a high degree of occupant safety. In these moderate-hazard occupancies, the occupants are typically very familiar with the building and the means of egress system. It is expected that they are aware of the operational limits of the inactive door leaf and efficiently use the active leaf. In both exceptions, it is mandated that the inactive leaf not be provided with any hardware, such as levers or panic devices that might cause the user to assume the door is an active egress door. The presence of door hardware on the active leaf will provide the necessary expectation to the building occupants, as occupants will naturally approach the active leaf having the appropriate hardware. If the building is sprinklered throughout with an NFPA 13 system, there is no limit on occupant load assigned to the pair of egress doors other than that based on the required capacity of the active leaf. The inactive leaf cannot be assumed to provide for any required egress capacity. This ensures that the occupants have a fully complying door available for means of egress purposes. The mandate that the building be fully sprinklered further enhances occupant safety and provides recognition from a general perspective of the value of a fire suppression system. An allowance is also provided for pairs of doors that serve relatively small numbers of people in the occupancies identified. The limit of 49 occupants is consistent with various other means of egress requirements that allow for a reduced level of protection where the occupant load does not exceed 50. Under this exception, the building is not required to be sprinklered. An overview of the provisions is shown in Figure 1010-14.

Figure 1010-14 Door hardware on a pair of doors.

A fifth exception addresses those patient room doors in Group I-2 occupancies where additional clear width is needed to allow for the efficient movement of patients and equipment. Where a pair of doors is used to provide the increased opening size, self-latching edge- or surface-mounted bolts may be installed on the inactive leaf. In order to distinguish that the inactive leaf is not an egress door, no lever device or other type of operating hardware is permitted. In addition, the inactive leaf cannot account for any of the minimum required egress width of 41½ inches (1,054 mm).

1010.1.9.5   Unlatching.   The installation of multiple devices, or hardware requiring multiple operations, is inappropriate as well. Special effort and special knowledge is often necessary to open a door where more than one operation is required to unlock or unlatch the door. As a result, the multiple operations will typically result in an unacceptable delay in the egress efforts. Four exceptions set forth applications where multiple unlatching or unlocking operations are acceptable.

1010.1.9.6   Controlled egress doors in Groups I-1 and I-2.   Group I-1 and I-2 facilities often house dementia and Alzheimer’s patients. In order to balance the needs of the facility with the life safety of the occupants, the limitations on locking devices in these types of uses must allow for a safe and secure environment for these patients within the means of egress concepts of the code. Locks are permitted on means of egress doors that serve Group I-1 and I-2 care recipients whose movement is restrained provided a number of conditions are met. Many of the conditions are similar to those set forth in Section 1010.1.9.7 for delayed egress locks. The building must be fully sprinklered or provided with an approved smoke or heat detection system. The doors must unlock upon actuation of the sprinkler or fire-detection system, the loss of power to the lock or lock mechanism, or by a signal from the nursing station or other approved location. The staff must also have the means to unlock the doors when necessary. As a further condition, it is mandated that occupants need only pass through one door equipped with this special egress device prior to entering an exit element. In all cases, the door locking system must be in conformance with UL 294.

Where patients with mental disabilities are housed, it is often necessary that they be restrained or contained for their own safety. In such cases, the level of restraint must be maintained even if the fire protection systems are activated or the power to the lock fails. However, it is still important that the emergency preparedness plan be developed and the clinical staff has the ability to monitor and enable the evacuation. See Figure 1010-15. The provisions are also applicable where the locking system is used in nursery and obstetric areas of Group I-2 hospitals to reduce the risk of child abduction.

Figure 1010-15 Locks on egress doors of Group I-1 and I-2 occupancies.

1010.1.9.7   Delayed egress.   The building code provides for a degree of security to egress doors serving all occupancies other than Groups A, E, and H. This section allows the use of a door that has an egress-control device with a built-in time delay under specific conditions. These devices were introduced in the code to resolve the problem of an exit door being illegally blocked by building operators desperate to stop the theft of merchandise through unsupervised, secondary exits. Institutional and residential occupancies are included because it is perceived that they also have security problems that need to be addressed. The devices are sometimes needed in nursing homes or group-care where facility operators must restrict patient egress while still maintaining viable exit systems.

It must be emphasized that under the conditions imposed by this section, and within the reliability of the automatic systems required, there will be no delay whatsoever at the exit in an actual fire emergency—the door will be immediately openable.

Delayed egress locking conditions. Several conditions should be emphasized at the outset:

1.   Such devices may be used only in connection with the specifically listed occupancies.

2.   The entire building in which the delayed egress locking system is installed must be completely protected throughout by either an approved automatic sprinkler system or an approved automatic smoke- or heat-detection system.

3.   In other than Group I-2 and I-3 occupancies, a building occupant shall not be required to pass through more than one door equipped with a delayed egress lock before entering an exit.

4.   The door shall unlock in compliance with the following criteria: The device must immediately and automatically deactivate on activation of the sprinkler system or fire-detection system, and on the loss of electrical power to the egress lock. There must also be a way of manually deactivating the device by the operation of a signal from the fire command center where provided. Where the operating device is activated, it must initiate an irreversible process that will cause the delayed egress lock to deactivate whenever a manual force of not more than 15 pounds (66 N) is applied for a minimum period of 3 seconds to the operating hardware. The irreversible process must achieve the deactivation of the device within a time period of not more than 15 seconds from the time the operating hardware is originally activated. Where approved by the building official, a delay of not more than 30 seconds is permitted. Upon activation of the operating hardware, an audible signal shall be initiated at the door so that the person attempting to exit the building will be aware that the irreversible process has been started.

A sign must be installed on the door above and within 12 inches (305 mm) of the operating hardware so that the person seeking egress can be informed as to the type and nature of the egress lock. The sign must read PUSH (PULL) UNTIL ALARM SOUNDS. DOOR CAN BE OPENED IN 15 (30) SECONDS. An additional requirement requires emergency lighting to be provided at the door where the delayed egress lock is used. In all cases, the delayed egress locking system must comply with UL 294.

Delayed egress lock reactivation. The code emphasizes that, regardless of the means of deactivation, relocking of the device shall only be by manual means at the door. This requirement ensures that to relock the delayed egress lock, someone must go to the door itself, verify that the emergency no longer exists, and only then relock the door by manual means.

1010.1.9.8   Sensor release of electrically locked egress doors.   Security concerns have prompted the need to provide controlled access at entrance doors to buildings or tenant spaces of certain occupancies. Therefore, this section permits the use of an approved entrance and egress access-control system at the main entrance of a Group A, B, E, I-1, I-2, I-4, M, R-1, or R-2 occupancy. Sensor-released egress doors will typically be locked from the exterior at all times. In order to ensure that the door is fully operable during a fire incident or other emergency, a number of criteria have been developed. For the most part, when a problem situation is identified, the door operates in a manner like any other egress door. Activation of the building fire alarm, automatic sprinkler system, or fire detection system will automatically unlock the door. Unlocking must also be possible from a location adjacent to the door, or occur when there is loss of power to the access-control system. It is important to note that the security device must be listed in accordance with UL 294, Access Control System Units.

1010.1.9.9   Electromagnetically locked egress doors.   As a general rule, means of egress door hardware must be operable by manual operation to provide for occupant control of the egress system. Locking devices are typically prohibited, as they can interfere or prevent efficient egress through the door during an emergency situation. However, owner concerns that must be considered sometimes require a greater degree of security. In specific occupancies, doors in the means of egress are permitted to be electromagnetically locked if equipped with listed hardware that incorporates a built-in switch that interrupts the power supply to the electromagnetic lock and unlocks the door. The use of this type of locking system provides for a greater degree of security than that offered by other methods addressed in the code, including delayed egress locking systems and access control egress systems.

The allowance for electronically locked egress doors is limited to low- and moderate-hazard occupancies where security can be a major concern. The listed hardware that incorporates a built-in switch is required to comply with UL 294. When the occupant prepares to use the door hardware, the method of operating the hardware must be obvious, even under poor lighting conditions. The operation shall be accomplished through the use of a single hand. This is consistent with the general requirement that the door be readily openable without the use of special knowledge or effort. The unlocking of the door must occur immediately on the operation of the hardware by interrupting the power supply to the electromagnetic lock. As an additional safeguard, the loss of power to the hardware shall automatically unlock the door.

This special type of locking device is permitted to be used in conjunction with panic hardware and fire exit hardware, but only where operation of such hardware also releases the electromagnetic lock.

1010.1.9.1   Stairway doors.   The general requirement for interior stairway doors is that they be openable from both sides without the use of a key or special knowledge or effort. Such conditions allow for immediate access from the stairway enclosure to the adjacent floor area for emergency responders. In addition, in the unlikely event that the stairwell becomes untenable during evacuation procedures, occupants may reenter a floor level as an alternative means of egress. However, five exceptions are provided to modify this requirement.

1.   Those doors that provide egress from the stair enclosure, discharging directly to the exterior or to an egress component leading to the exterior, are permitted to be locked only on the side opposite the direction of egress travel.

2.   In high-rise buildings, stairway doors, other than exit discharge doors, may be locked from the stairway side. Under these conditions, such doors must be capable of being unlocked simultaneously without unlatching upon a signal from the fire command center. Although this exception is not limited to use in high-rise buildings, it is most commonly applied in such situations. When used in buildings that are not considered high-rise, the criteria of Section 403.5.3 may also be applied.

3.   Doors are permitted to be locked from the side opposite the egress side for stairways serving four or fewer stories, where emergency personnel have the ability to simultaneously unlock the door. This action must be accomplished upon a signal from a single interior location at the building’s main entrance, with the specific location for the actuating device likely approved by the fire code official. Where the building is provided with a fire command center, the signal must be actuated from within the center. It is important that the unlocking signal not deactivate the latching devices of the stairway doors. The doors must remain latched in order to maintain their integrity as fire door assemblies.

4.   Applicable only to two-story buildings housing a Group B, F, M, or S occupancy, this exception permits the locking of the stairway door from the stairway side provided the only interior access to the tenant space is a single exit stair. Under specified conditions in Section 1006.3.2, a single exit is permitted from the basement or second story of the moderate-hazard occupancies scoped in this exception. Where a single exit stair is acceptable due to a limited occupant load and travel distance, it is permissible to lock the door to the tenant space from the stairway side.

5.   This exception is similar in application to Exception 4.

1010.1.10   Panic and fire exit hardware.   Basically, panic hardware is an unlatching device that will operate even during panic situations, so that the weight of the crowd against the door will cause the device to unlatch. This provision of the code, in harmony with the need to swing the door in the direction of egress travel, is intended to prevent the type of disaster experienced in the Cocoanut Grove fire in Boston in 1942. When a panic hardware device is installed on a door leaf, the press of the crowd, which prevented the opening of the door in the Cocoanut Grove fire, will ensure the automatic opening of the door.

Where panic hardware is provided, it is necessary that the activating member of the device extend for at least one-half of the width of the door leaf. This minimum length ensures that the unlatching operation will take place when one or more individuals impact the door. In addition, the device must be arranged so that a horizontal force not exceeding 15 pounds (66 N), when applied in the direction of exit travel, will unlatch the door.

Where required. Because of the large concentration of people in an assembly occupancy that may reach an exit door at about the same time during an emergency, the Group A occupancy is one of those occupancy groups that requires the installation of panic hardware listed in accordance with UL 305. Such hardware is also required in Group E occupancies for essentially the same reason. Therefore, in these two occupancies, any egress door provided with a latching or locking device that serves a room or area having an occupant load of 50 or more must be provided with panic hardware. In addition, in all Group H occupancies, panic hardware is required on every egress door regardless of the occupant load served. The potential life-safety hazard in these Group H occupancies is such that when it is necessary to evacuate this type of use, exiting from such spaces must be almost immediate. To facilitate the rapid escape from these occupancies, egress doors shall not be provided with a latch or lock unless it is panic hardware. Again, it should be noted that if a door is used in a situation where panic hardware might otherwise be required, it is not necessary to install panic hardware if the door has no means for locking or latching. If the door is free to swing at all times, there is no need to install panic hardware to overcome a lock or latch. Panic hardware is also not mandated on those doors considered as the main exit in a Group A occupancy having an occupant load of 300 or less where the provisions of Section 1010.1.9.3, Item 2, are applied, permitting the use of key-operated locking devices. Electromagnetically lock doors complying with Section 1010.1.9.9 are also permitted in lieu of panic hardware.

Panic hardware on balanced doors. Special care must be taken when installing panic hardware on balanced doors. In this instance, push-pad-type panic hardware is to be used, and it must be installed at one-half of the door width nearest the latch side to avoid locating the pad too close to the pivot point.

Section 1010.1.2 requires that exit doors should be side-hinged or pivoted swinging doors. The typical pivoted door has its top and bottom pivot points located near the edge of the door frame opposite the latch side. Balanced doors are nothing more than a specialized type of pivoted door in which the pivot point is located some distance inboard from the door edge, creating a counter-balancing effect. The length of the panic bar is limited for balanced doors because the door cannot be opened if the opening force is applied too close to the pivot point or beyond. Limiting the panic bar length to one-half the door width ensures that those who use the door will apply opening pressure at a distance sufficiently removed from the pivot point to allow the door to open. See Figure 1010-16.

Figure 1010-16 Panic hardware on balanced doors.

1010.2   Gates.   This section serves as a reminder that gates within the means of egress system must comply with all of the requirements for doors. The single exception, applicable only to fences and walls surrounding stadiums, overrides the general door requirement that the doors must swing, and that the width of any leaf cannot exceed 4 feet (1,219 mm).

1010.2.1   Stadiums.   Facilities such as stadiums may be enclosed by fencing or similar enclosures. The requirement for panic hardware does not apply to gates through such enclosures, provided that the gates are under constant and immediate supervision while the stadium is occupied. However, there must be a safe dispersal area of a size sufficient to accommodate the occupant load of the stadium based on 3 square feet (0.28 m²) per person, and located between the stadium and the fence or other enclosure. Such a dispersal area must not be less than 50 feet (15,240 mm) from the stadium it serves.

1010.3   Turnstiles.   In order to address safety concerns that are due to the use of turnstiles or similar devices that may be placed along the path of exit travel, this section regulates their use when located in a manner to restrict travel to a single direction. The general rule requires that each turnstile be credited with a maximum capacity of 50 occupants, and then only when specific conditions are met. When primary power is lost, the device shall turn freely in the direction of egress travel. Release shall also occur upon manual operation by an employee in the area. When determining the overall egress capacity, turnstiles may only be considered for up to 50 percent of the required capacity. Each device is limited to 39 inches (991 mm) in height and must have a minimum clear width of 16½ inches (419 mm) at and below the height of 39 inches (991 mm). Above the 39-inch (991-mm) height, a clear minimum width of 22 inches (559 mm) is necessary. Obviously, variations in these requirements are necessary where the turnstile is located along an accessible route of travel. Where turnstiles exceed 39 inches (991 mm) in height, they are regulated in a manner consistent with revolving doors.

To address the concern for use of such devices in large occupancies, Section 1010.3.2 requires a side-hinged swinging door for devices other than portable turnstiles. Required at a point where the occupant load served exceeds 300, a swinging door must be located within 50 feet (15,240 mm) of each turnstile. Portable turnstiles are designed to be moved out of the way for large occupancies such as sporting events.

Section 1011 Stairways

In order to apply the requirements of this section on stairways in an appropriate manner, the scope of the provisions must be determined. The definition of a stairway is critical for this determination. Found in Section 202, the definition consists of two parts. First, a stair is considered a change of elevation accomplished by one or more risers. Second, one or more flights of such stairs make up a stairway, along with any landings and platforms that connect to them. Based on these two definitions, a single step would also be considered a stairway under the IBC.

1011.1   General.   The scoping provision for this section indicates that the requirements of Section 1011 apply to any stairway serving an occupied portion of a building, eliminating the potential for inappropriate interpretations that view stairways not required as a means of egress as not regulated by Chapter 10 nor the provisions of Section 1011. Whether stairways are serving as a required portion of the egress system or simply installed in additional numbers beyond the code minimum, as “convenience” stairs, it is appropriate for all stairways to meet the minimum safeguards that the code intends.

1011.2   Width and capacity.   The provisions concerning minimum width and required capacity of stairways are analogous to the provisions relating to corridors discussed in Section 1020.2. If the stair is subject to use by a sufficiently large occupant load, the minimum required width of the stair is determined by using the formula stated in Section 1005.3.1. Otherwise, its required width cannot be less than the width established by this section. In general terms, the minimum required width of any stair must be at least 44 inches (1,118 mm). In the event the stairway serves an occupant load of 49 or less, the required minimum width of the stairway is only 36 inches (914 mm). The entire occupant load of the story served by the stairway is considered, rather than divided by all available stairways. See Application Example 1011-1. Other modifications to the width requirements apply to spiral stairways as addressed in Section 1011.10, stepped aisles regulated under the provisions of Section 1029, and stairways that are provided with an incline platform lift or stairway chairlift. Generally, when the code specifies a required width of a component in the egress system, it intends that width to be the clear, net, usable unobstructed width. However, handrails and other projections are permitted to encroach into the required capacity or minimum width of a stairway as established by the provisions of Section 1014.8.

Application Example 1011-1

1011.3   Headroom.   A minimum headroom clearance of 6 feet 8 inches (2,032 mm) is required in connection with every stairway. Such required clearances shall be measured vertically from the leading edge of the treads to the lowest projection of any construction, piping, fixture, or other object above the stairs, and shall be maintained for the full width of the stairway and landing. See Figure 1011-1. This specific height requirement overrides the general means of egress ceiling height requirement found in Section 1003.2 and is modified for spiral stairways by Section 1011.10.

Figure 1011-1   Stairway headroom clearance.

1011.5.2   Riser height and tread depth.   This section provides for a maximum riser height of 7 inches (178 mm), a minimum riser of 4 inches (102 mm), and a minimum tread run of 11 inches (279 mm) for each step on any stairway. These limiting dimensions are identified in Figure 1011-2. Variations in the requirements for treads and risers apply to alternating tread devices, spiral stairways, and stepped aisles in assembly seating areas. These variations are discussed elsewhere in this chapter. Another exception allows 7¾ inches (197 mm) maximum and 10 inches (254 mm) minimum for rise and run, respectively, for stairways in Group R-3 occupancies, within dwelling units in Group R-2 occupancies, and in Group U occupancies accessory to a Group R-2 or R-3 dwelling unit.

Figure 1011-2   Rise and run.

The 7-inch (178-mm) rise and 11-inch (279-mm) run figures for the steps are based primarily on safety in descending the stairs and are the result of much research. Probably at no prior time in the history of codes has the proportionate of stairs enjoyed a better foundation in research.

As one descends a stairway, balance is essential for safety. Therefore, the tread run must be of such a dimension as to permit the user to balance comfortably on the ball of the foot. The appropriate combination of riser height and tread run provides the proper geometry to enable the user to accomplish the necessary balance to descend the stairway with reasonable safety. Consistent with the importance of the tread dimension, the method of measurement of the tread is expressly stated. Specifically, tread depth (or run) is that distance measured horizontally between vertical planes passing through the foremost projections of adjacent treads. As such, the tread dimension is the net gain in the run of the stair. Tread dimension is measured in this manner because any tread surface underneath the overhang of a sloping riser or nosing on the tread above is not available to the person descending the stair. Because descending is the more critical direction, proper dimension of the tread is of paramount importance.

Studies of people traveling on stairways have shown that probably the greatest hazard on a stair is the user. Inattention has been identified as the single factor producing the greatest number of missteps, accidents, and injuries. Inattention frequently results from the user being overly familiar with the stair and its surroundings. It often results from a variety of distractions. It is critical to stair safety that the stair user be attentive to the stair, although attentiveness cannot be codified or dictated. However, stair design and geometry, which usually trigger human error, can be controlled.

Curved stairways, along with spiral stairways, represent somewhat of an exception to what is normally considered a traditional stairway. Where the typical stairway is required to have treads of a consistent and uniform size and shape, these two stairs may have different dimensional characteristics from adjacent treads and vary from one end of the tread to the other. Alternating tread devices and ships ladders are additional types of vertical travel components whose design is inconsistent with that of a typical stairway. The use of these components as a portion of the means of egress system varies; however, only curved stairways may be used as a part of the means of egress in all occupancies and locations.

1011.5.4   Dimensional uniformity.   A significant safety factor relative to stairways is the uniformity of risers and treads in any flight of stairs. The section of a stairway leading from one landing to the next is defined as a flight of stairs. It is very important that any variation that would interfere with the rhythm of the stair user be avoided. Although it is true that adequate attention to the use of the stair can compensate for substantial variations in risers and treads, it is all too frequent that the necessary attention is not given by the stair user.

To obtain the best uniformity possible in a flight of stairs, the maximum variation between the highest and lowest risers and between the widest and narrowest treads is limited to ⅜ inch (9.5 mm). This tolerance is not intended to be used as a design variation, but it does recognize that construction practices make it difficult to get exactly identical riser heights and tread dimensions in constructing a stairway facility in the field. Therefore, the code allows the variation indicated in Figure 1011-3. Although the code allows for a tolerance in both the tread depth and riser height, this tolerance is not intended to permit a reduction in the minimum tread depth or increase in the maximum riser height established by the IBC. For example, a tread depth of 10⅝ inches (270 mm) is not permitted if a minimum of 11 inches (279 mm) is required, nor is a riser height of 7⅜ inches (188 mm) acceptable where the code limits riser height to 7 inches (178 mm).

Figure 1011-3   Stair tolerance.

Under the provisions of Section 1029.13.2, riser height nonuniformity is permitted for stepped aisles where changes in the gradient of the adjoining assembly seating area are necessitated in order to maintain adequate lines of sight. Another exception permits the transition between a typical straight run stairway and consistently shaped winders under the conditions of Section 1011.5.

1011.5.4.1   Nonuniform height risers.   With respect to variation, it is recognized that stairs occasionally descend or rise to areas where the ground or the finished surface is sloping. Where this occurs on private property, the code anticipates that the landing of the stairs be level so that there will not be any variation in the riser height across the width of the stair at that point. However, from time to time, stairs will land on spaces that are not under the control of the property owner, such as a public sidewalk. Therefore, a certain degree of slope across the width of the stair is permitted, resulting in a variation of the height of the riser from one side of the stair to the other. Where this occurs, the height of such a riser may be reduced along the slope to less than 4 inches (102 mm), and the maximum permitted slope shall not exceed 1 unit vertical in 12 units horizontal (8.3-percent slope). Figure 1011-4 shows this condition. It should be clarified that the sloping surface is intended to be an established grade, such as a walkway, public way, or driveway.

Figure 1011-4   Sloping landing.