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SECTION 1028 ASSEMBLY

1028.1 General. Occupancies in Group A and assembly occupancies accessory to Group E which contain seats, tables, displays, equipment or other material shall comply with this section.


Although most of the provisions in Section 1028 focus on fixed seating auditoriums or theaters, this section also addresses loose seats, tables, displays, equipment, etc. For example, Section 1017.4 provides measurement criteria adjacent to seating at tables, but relies on Section 1028.9 to determine the required aisle width. Assembly spaces that contain elements that would affect the path of travel for the means of egress must comply with this section. Assembly spaces require special consideration due to the large occupant loads and possible low lighting (e.g., nightclubs, theaters). The group description of educational facilities allows for some accessory assembly spaces to be considered Group E for height and area limitation, type of construction, sprinkler requirements, etc. Not all assembly spaces associated with Group E are accessory. For additional explanations, see the commentary to Section 305.1. However, for evaluation of the occupant load and the means of egress in these spaces, they should be regulated based on their function, rather than their occupancy group.




1028.1.1 Bleachers. Bleachers, grandstands and folding and telescopic seating, that are not building elements, shall comply with ICC 300.


On February 24, 1999, the Bleacher Safety Act of 1999 was introduced in the House of Representatives. The bill, which cites the ICC and the code, authorizes the Consumer Product Safety Commission (CPSC) to issue a standard for bleacher safety. This was in response to concerns relative to accidents on bleacher-type structures. As a result, the CPSC developed and revised the Guidelines for Retrofitting Bleachers. The ICC Board of Directors decided that a comprehensive standard dealing with all aspects of both new and existing bleachers was warranted and authorized the formation of the ICC Consensus Committee on Bleacher Safety. The committee is comprised of 12 members, including the requisite balance of general, user interest and producer interest.

ICC 300 was completed in December 2001, and submitted to ANSI on January 1, 2002. ICC 300 was reissued with some revisions in 2007. While the term "bleachers" is generic, the standard addresses all aspects of tiered seating associated with bleachers, grandstands and folding and telescopic seating. These types of seating are supported on dedicated structural systems, which in turn may sit on the ground or on a building floor system. Single seats or bench seats bolted down to a stepped floor are not considered a bleacher or grandstand and should comply with Section 1028. "Building element" is defined in Section 702.1, while "Bleachers," "Grandstands" and "Folding and telescopic seating" are defined in Section 1002.1. While ICC 300 is consistent and also relies on Chapter 10 of the code for some provisions, the standard addresses items specific to these types of seating arrangement. The bleacher standard references Chapter 11 of the code and ICC A117.1 for accessibility requirements.

1028.2 Assembly main exit. Group A occupancies and assembly occupancies accessory to Group E occupancies that have an occupant load of greater than 300 shall be provided with a main exit. The main exit shall be of sufficient width to accommodate not less than one-half of the occupant load, but such width shall not be less than the total required width of all means of egress leading to the exit. Where the building is classified as a Group A occupancy, the main exit shall front on at least one street or an unoccupied space of not less than 10 feet (3048 mm) in width that adjoins a street or public way.

Exception: In assembly occupancies where there is no well-defined main exit or where multiple main exits are provided, exits shall be permitted to be distributed around the perimeter of the building provided that the total width of egress is not less than 100 percent of the required width.


Assembly buildings as well as other buildings that include spaces that function as assembly spaces (i.e., the band classroom in a school, the training room in an office, the cafeteria in a large factory) present an unusual life safety problem that includes frequent high occupant densities and therefore large occupant loads and the opportunity for irrational mass response to a perceived emergency, i.e., panic. For this reason, the code requires a specific arrangement of the exits. Studies have indicated that in any emergency, occupants will tend to egress via the same path of travel used to enter the room and building. Therefore, a main entrance to the building must also be designed as the main exit to accommodate this behavior, even if the required exit capacity might be more easily accommodated elsewhere. The main entrance (and exit) must be sized to accommodate at least 50 percent of the total occupant load of the structure and must front on a large, open space, such as a street, for rapid dispersal of the occupants outside the building. The remaining exits must also accommodate at least 50 percent of the total occupant load from each level (see Figure 1028.2). The total occupant load includes those within the theater seating area, the foyer and any other space (e.g., ticket booth, concession stand, offices, storage and the like). When the assembly space is within a mixed use building, the intent is that the main exits from the space comply with these provisions for one-half the capacity, but not necessarily that they lead directly to the outside. Egress requirements from the building would depend on how it was anticipated for the assembly space occupants to disperse. For example, an office building may have a large training/conference room where the path of exit access travel from the room goes out a main exit from the space and then disseminates into the general floor egress system. While the room exit access doors may need to meet the 50 percent criteria, the exception may be applicable once the occupants leave the room and enter the general floor egress system.

The required width of the means of egress in places of assembly is more often determined by the occupant load than in most other occupancies. In other occupancies, the minimum required widths and the travel distances will often determine the required widths of the exits.

This section only requires the main exit to accommodate 50 percent of the occupant load when there is a single main entrance. Therefore, a large stadium or civic center, in which there are numerous entrances (and exits), need not comply with the main entrance criteria. This condition is addressed in the exception.





Figure 1028.2 GROUP A-1 WITH WAITING SPACE



1028.3 Assembly other exits. In addition to having access to a main exit, each level in Group A occupancies or assembly occupancies accessory to Group E occupancies having an occupant load greater than 300, shall be provided with additional means of egress that shall provide an egress capacity for at least one-half of the total occupant load served by that level and comply with Section 1015.2.

Exception: In assembly occupancies where there is no well-defined main exit or where multiple main exits are provided, exits shall be permitted to be distributed around the perimeter of the building, provided that the total width of egress is not less than 100 percent of the required width.


This section provides for the egress of one-half of the total occupant load by way of exits other than the main exit that is described in Section 1028.2. The exception addresses assembly spaces, such as a school gymnasium or a large stadium or civic center in which there are numerous entrances (and exits), none of which are a main entrance or exit.



1028.4 Foyers and lobbies. In Group A-1 occupancies, where persons are admitted to the building at times when seats are not available, such persons shall be allowed to wait in a lobby or similar space, provided such lobby or similar space shall not encroach upon the required clear width of the means of egress. Such foyer, if not directly connected to a public street by all the main entrances or exits, shall have a straight and unobstructed corridor or path of travel to every such main entrance or exit.


In theaters, people may be arriving for the next show while another group has yet to exit. This is extremely common in multiplex theater complexes. In every case, the main entrance (exit) and all other exits are to be constantly available for the entire building occupant load.

For example, because of the queuing of large crowds, particularly in theaters where a performance may be in progress and people must wait to attend the next one, standing space is often provided. For reasons of safety, such spaces cannot be located in or interfere with established paths of egress from the assembly areas. While a facility may choose to separate the route for means of egress using partitions or railings from the general lobby space to allow for easy traffic flow through the lobby to the street, it is not required to designate these areas (see Figure 1028.2).



1028.5 Interior balcony and gallery means of egress. For balconies, galleries or press boxes having a seating capacity of 50 or more located in Group A occupancies, at least two means of egress shall be provided, with one from each side of every balcony, gallery or press box and at least one leading directly to an exit.


This section states the threshold where two means of egress are required based on the occupant load of the interior balcony, gallery or press box. Note that one of the means of egress must lead directly to an exit. However, Section 1028.5.1 does not require the stairways serving the balcony to be enclosed in an exit enclosure. These requirements will ensure that at least one path of travel is always available and occupants face a minimum number of hazards.

For balconies with 50 or fewer occupants, see Section 1028.8.




1028.5.1 Enclosure of openings. Interior stairways and other vertical openings shall be enclosed in an exit enclosure as provided in Section 1022.1, except that stairways are permitted to be open between the balcony, gallery or press box and the main assembly floor in occupancies such as theaters, places of religious worship, auditoriums and sports facilities. At least one accessible means of egress is required from a balcony, gallery or press box level containing accessible seating locations in accordance with Section 1007.3 or 1007.4.


This section allows the stairways that lead from interior balconies, galleries and press boxes to be unenclosed from those spaces to the main floor where the interior balconies are within large assembly spaces, such as theaters, places of religious worship, auditoriums and sports arenas. Thus, vertical exit enclosures are not required for stairways or ramps leading to these facilities. When these areas contain accessible wheelchair spaces (see Sections 1104.3.2 and 1108.2), at least one means of egress must be accessible. While the section references only indicate exit stairways or elevators (see Sections 1007.3 and 1007.4), there are special allowances for the use of platform lifts (see Sections 1007.5 and 1109.7, Item 2) in assembly spaces to allow for dispersion of wheelchair spaces to a variety of locations. This is especially important in assembly spaces with sloped or tiered seating. Section 1007.5 states that if a platform lift is permitted as part of an accessible route, it should also be permitted as part of the accessible means of egress if it is provided with standby power.

1028.6 Width of means of egress for assembly. The clear width of aisles and other means of egress shall comply with Section 1028.6.1 where smoke-protected seating is not provided and with Section 1028.6.2 or 1028.6.3 where smoke-protected seating is provided. The clear width shall be measured to walls, edges of seating and tread edges except for permitted projections.


The means of egress width for assembly occupancy is to be in accordance with this section and the referenced sections instead of the criteria specified in Section 1005.1. The width factors in Section 1028.6 and its subsections apply to those stairs, aisle steps, corridors, passageways and ramped surfaces that serve the assembly seating areas.

Different means of egress width criteria are also specified for assembly seating where smoke protection is provided versus areas it is not provided. The egress width for smoke-protected seating is allowed to be less than for areas where smoke protection is not provided, since the smoke level is required to be maintained at least 6 feet (1829 mm) above the floor of the means of egress, according to Section 1028.6.2.1.




1028.6.1 Without smoke protection. The clear width of the means of egress shall provide sufficient capacity in accordance with all of the following, as applicable:
1. At least 0.3 inch (7.6 mm) of width for each occupant served shall be provided on stairs having riser heights 7 inches (178 mm) or less and tread depths 11 inches (279 mm) or greater, measured horizontally between tread nosings.
2. At least 0.005 inch (0.127 mm) of additional stair width for each occupant shall be provided for each 0.10 inch (2.5 mm) of riser height above 7 inches (178 mm).
3. Where egress requires stair descent, at least 0.075 inch (1.9 mm) of additional width for each occupant shall be provided on those portions of stair width having no handrail within a horizontal distance of 30 inches (762 mm).
4. Ramped means of egress, where slopes are steeper than one unit vertical in 12 units horizontal (8-percent slope), shall have at least 0.22 inch (5.6 mm) of clear width for each occupant served. Level or ramped means of egress, where slopes are not steeper than one unit vertical in 12 units horizontal (8-percent slope), shall have at least 0.20 inch (5.1 mm) of clear width for each occupant served.


This section prescribes the criteria needed to calculate the clear widths of aisles and aisle accessways in order to provide sufficient capacity to handle the occupant loads established by the "catchment areas" described in Section 1028.9.2. Clear width is to be measured to walls, edges of seating and tread edges.

The criteria for determining the required widths are based on analytical studies and field tests that used people to model egress situations [see Figures 1028.6.1(1) and 1028.6.1(2)].

Criterion 1 addresses the method for determining the required egress width for aisles and aisle accessways that are stepped. This method corresponds with the requirements of Table 1005.1 for egress width per occupant of stairways in an unsprinklered building.

Criterion 2 addresses the method for determining the additional stair width required for aisle and aisle accessway stairs with risers greater than 7 inches (178 mm).

Criterion 3 addresses the method for determining the additional stair width where a handrail is not located within 30 inches (762 mm).

Criterion 4 addresses the method for determining the required widths for level or ramped means of egress.





For SI: 1 inch = 25.4 mm.


Figure 1028.6.1(1) COMPUTATION OF WIDTH FOR STEPPED AISLES





For SI: 1 inch = 25.4 mm.


Figure 1028.6.1(2) COMPUTATION OF WIDTH FOR LEVEL, SLOPED OR RAMPED AISLES

1028.6.2 Smoke-protected seating. The clear width of the means of egress for smoke-protected assembly seating shall not be less than the occupant load served by the egress element multiplied by the appropriate factor in Table 1028.6.2. The total number of seats specified shall be those within the space exposed to the same smoke-protected environment. Interpolation is permitted between the specific values shown. A life safety evaluation, complying with NFPA 101, shall be done for a facility utilizing the reduced width requirements of Table 1028.6.2 for smoke-protected assembly seating.

Exception: For an outdoor smoke-protected assembly with an occupant load not greater than 18,000, the clear width shall be determined using the factors in Section 1028.6.3.


Special consideration is given to facilities with features that will prevent the means of egress from being blocked by smoke. Facilities to be considered smoke protected by Sections 1028.6.2.1 through 1028.6.2.3 are permitted increases in travel distance, egress capacity, longer dead-end aisles and increased row lengths. All of these result in an increase of allowable egress time. Typically, model codes based on research by Dr. John Fruin and others recognize the need for occupants exposed to the fire environment to evacuate to a safe area within 90 seconds of notification and to reach an area of refuge within 5 minutes. With the increases permitted for smoke-protected facilities, these times are effectively doubled since the time available for safe egress also increases.

The exception is a pointer to the specific criteria for outdoor seating areas. For outdoor stadiums with 18,000 seats or greater, use Table 1028.6.2.



TABLE 1028.6.2 WIDTH OF AISLES FOR SMOKE-PROTECTED ASSEMBLY

TOTAL NUMBER OF SEATS IN THE SMOKE-PROTECTED ASSEMBLY OCCUPANCY
INCHES OF CLEAR WIDTH PER SEAT SERVED
Stairs and aisle steps with handrails within 30 inches
Stairs and aisle steps without handrails
within 30 inches
Passageways, doorways and ramps not steeper than 1 in 10 in slope
Ramps steeper
than 1 in 10 in slope
Equal to or less than 5,000
0.200
0.250
0.150
0.165
10,000
0.130
0.163
0.100
0.110
15,000
0.096
0.120
0.070
0.077
20,000
0.076
0.095
0.056
0.062
Equal to or greater than 25,000
0.060
0.075
0.044
0.048


For SI: 1 inch = 25.4 mm.



This section requires the egress component to be of adequate size to accommodate the occupant load. The egress width per occupant for nonsmoke-protected seating is to be based on Section 1028.6.1 and is similar to the provisions in Table 1005.1. For smoke-protected seating, the egress width per occupant is based on Table 1028.6.2.

1028.6.2.1 Smoke control. Means of egress serving a smoke-protected assembly seating area shall be provided with a smoke control system complying with Section 909 or natural ventilation designed to maintain the smoke level at least 6 feet (1829 mm) above the floor of the means of egress.


The means of egress and the assembly seating area are required to have some type of smoke control system that will prevent smoke buildup from encroaching on the egress path. This may be a mechanical smoke control system, designed in accordance with Section 909, or a natural ventilation system.

In either type of system, the major consideration is that a smoke-free environment be maintained at least 6 feet (1829 mm) above the floor of the means of egress for a period of at least 20 minutes.

1028.6.2.2 Roof height. A smoke-protected assembly seating area with a roof shall have the lowest portion of the roof deck not less than 15 feet (4572 mm) above the highest aisle or aisle accessway.

Exception: A roof canopy in an outdoor stadium shall be permitted to be less than 15 feet (4572 mm) above the highest aisle or aisle accessway provided that there are no objects less than 80 inches (2032 mm) above the highest aisle or aisle accessway.


One element of a smoke-protected assembly seating facility is that the lowest portion of the roof is required to be at least 15 feet (4572 mm) above the highest aisle or aisle accessway. The objective of this provision is to have a minimum 6-foot (1829 mm) smoke-free height to accommodate safe egress through the area. The additional 9 feet (2743 mm) of height is to provide a volume of space that will act to dissipate smoke. The measurement of the height is shown in Figures 1028.6.2.2(1) and 1028.6.2.2(2).





For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.






For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.


Figure 1028.6.2.2(2) ROOF HEIGHT (CONCAVE SUSPENDED ROOF)

1028.6.2.3 Automatic sprinklers. Enclosed areas with walls and ceilings in buildings or structures containing smoke-protected assembly seating shall be protected with an approved automatic sprinkler system in accordance with Section 903.3.1.1.

Exceptions:
1. The floor area used for contests, performances or entertainment provided the roof construction is more than 50 feet (15 240 mm) above the floor level and the use is restricted to low fire hazard uses.
2. Press boxes and storage facilities less than 1,000 square feet (93 m2) in area.
3. Outdoor seating facilities where seating and the means of egress in the seating area are essentially open to the outside.


If there are areas in the smoke-protected assembly seating structure enclosed by walls and ceilings, the entire structure is to be provided with an automatic sprinkler designed to meet the requirements of NFPA 13. NFPA 13R systems are not acceptable for this use.

Exception 1 indicates that the area over the playing field or performance area is not required to be sprinklered if the use of the floor area is restricted. If the facility is used for conventions, trade shows, displays or similar purposes, sprinklers would be required throughout, since the occupancy would no longer be a low fire-hazard use. A characteristic of a low fire-hazard occupancy is that the fuel load due to combustibles is approximately 2 pounds per square foot (9.8 kg/m2) or less.

In order for the contest, performance or entertainment area to be unsprinklered, the roof over that area must be at least 50 feet (15 240 mm) above the floor in addition to the floor area meeting the low fire-hazard criteria. The 50-foot (15 240 mm) criterion was selected because the response time for sprinklers at this height is extremely slow. It is estimated that the response time for standard sprinklers [50 feet (15 240 mm) above a floor with a fire having a heat release rate of 5 British thermal units (Btu) per square foot per second] exceeds 15 minutes. Therefore, it is not reasonable to install sprinklers at that height with little expectation of timely activation [see Figure 1028.6.2.3(1)]. Note that if this exception is utilized, the trade-offs for a fully sprinklered building, such as increased height and area limitations or decreased corridor ratings, are no longer permitted.

Exception 2 indicates that automatic sprinklers are not required in small spaces in buildings. Sprinklers are required in press box and storage areas of outdoor facilities when the aggregate area exceeds 1,000 square feet (93 m2). The primary reason for sprinklers in these areas is that both are anticipated to have a relatively large combustible load when compared to the main seating and participant areas. Additionally, in the case of storage areas, there is an increased potential for an undetected fire condition to occur [see Figure 1028.6.2.3(2)].

Exception 3 provides for outdoor seating facilities where smoke entrapment is not a safety concern.





For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.


Figure 1028.6.2.3(1) INDOOR SEATING SPRINKLERED AREAS (CONVEX DOME ROOF)





For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm,

           1 square foot = 0.0929 m2.


Figure 1028.6.2.3(2) INDOOR SEATING SPRINKLERED AREAS (CONCAVE SUSPENDED ROOF)

1028.6.3 Width of means of egress for outdoor smoke-protected assembly. The clear width in inches (mm) of aisles and other means of egress shall be not less than the total occupant load served by the egress element multiplied by 0.08 (2.0 mm) where egress is by aisles and stairs and multiplied by 0.06 (1.52 mm) where egress is by ramps, corridors, tunnels or vomitories.

Exception: The clear width in inches (mm) of aisles and other means of egress shall be permitted to comply with Section 1028.6.2 for the number of seats in the outdoor smoke-protected assembly where Section 1028.6.2 permits less width.


This section has the coefficients for the determination of the width of egress required for outdoor smoke-protected assembly areas. Note that the coefficients are significantly less when compared to the values in Section 1028.6.1 for assembly areas without smoke protection. The coefficients are also less than those for smoke-protected assembly seating in Table 1028.6.2 except for very large assembly areas. The exception in this section would apply where the coefficients in Table 1028.6.2 are less than those in this section.

Low coefficients are a result of the very low hazard of outdoor smoke-protected assembly areas.

Generally, an outdoor assembly area meets the smoke control requirements of Section 1028.6.1 by natural ventilation and does not require an automatic sprinkler system according to Section 1028.6.3, Exception 3.

1028.7 Travel distance. Exits and aisles shall be so located that the travel distance to an exit door shall not be greater than 200 feet (60 960 mm) measured along the line of travel in nonsprinklered buildings. Travel distance shall not be more than 250 feet (76 200 mm) in sprinklered buildings. Where aisles are provided for seating, the distance shall be measured along the aisles and aisle accessway without travel over or on the seats.

Exceptions:

1. Smoke-protected assembly seating: The travel distance from each seat to the nearest entrance to a vomitory or concourse shall not exceed 200 feet (60 960 mm). The travel distance from the entrance to the vomitory or concourse to a stair, ramp or walk on the exterior of the building shall not exceed 200 feet (60 960 mm).
2. Open-air seating: The travel distance from each seat to the building exterior shall not exceed 400 feet (122 m). The travel distance shall not be limited in facilities of Type I or II construction.


This section includes the travel distance limits for an assembly occupancy, which are the same as those in Table 1016.1. The travel distance is to be measured in the same path as the occupants would normally take to exit the facility.

Exception 1 provides an extended travel distance for smoke-protected assembly seating that meets the requirements of Sections 1028.6.1 through 1028.6.3. Exception 2 applies to outdoor open-air seating areas where the smoke and fire hazard is very low. The Type I and II construction referred to in this exception is described in Section 602.

1028.8 Common path of egress travel. The common path of egress travel shall not exceed 30 feet (9144 mm) from any seat to a point where an occupant has a choice of two paths of egress travel to two exits.

Exceptions:

1. For areas serving less than 50 occupants, the common path of egress travel shall not exceed 75 feet (22 860 mm).
2. For smoke-protected assembly seating, the common path of egress travel shall not exceed 50 feet (15 240 mm).


The maximum travel distance down a single access row of seating to a location where a patron would have two choices for a way out of the space is 30 feet (9144 mm). In smoke-protected seating, the common path of travel can be up to 50 feet (15 240 mm).

If the room or space (e.g., box, gallery or balcony) has 50 or fewer occupants, the travel distance can be increased to 75 feet (22 860 mm). For example, this allows for a path of travel from a box seat, out of the box and to a main aisle or even a corridor located outside the assembly room itself. When this section is referenced for accessible means of egress (see Section 1007.1, Exception 3), the utilization of Exception 1 would include the entire occupant load of the box, gallery or balcony, not just the number of wheelchair spaces and/or companion seats. Wheelchair spaces that are integrated into the general seating would have the same common path of travel distance of 30 feet (9144 mm) before the person needing the accessible route could choose two different paths for accessible means of egress. This provides the same level of protection for the persons in the accessible seating as provided for others within the space.

1028.8.1 Path through adjacent row. Where one of the two paths of travel is across the aisle through a row of seats to another aisle, there shall be not more than 24 seats between the two aisles, and the minimum clear width between rows for the row between the two aisles shall be 12 inches (305 mm) plus 0.6 inch (15.2 mm) for each additional seat above seven in the row between aisles.

Exception: For smoke-protected assembly seating there shall not be more than 40 seats between the two aisles and the minimum clear width shall be 12 inches (305 mm) plus 0.3 inch (7.6 mm) for each additional seat.


In establishing the point where the occupants of a row served by a single access aisle have two distinct paths of travel, the code allows one of those paths to be through the rows of an adjacent seating area or section. This requirement increases the row widths for the single-access seating section and the adjacent dual-access seating section. This allows the occupants to either travel down the single access aisle or readily traverse the oversized row widths to gain access to a second means of egress. This exception allows a greater number of seats spaced with a minimum clearance of 12 inches (305 mm) for smoke-protected assembly seating that complies with Sections 1028.6.2.1 through 1028.6.2.3 or Section 1028.6.3. For the base width requirements for single-and dual-access rows, see the commentary to Sections 1028.10 through 1028.10.2.

1028.9 Assembly aisles are required. Every occupied portion of any occupancy in Group A or assembly occupancies accessory to Group E that contains seats, tables, displays, similar fixtures or equipment shall be provided with aisles leading to exits or exit access doorways in accordance with this section. Aisle accessways for tables and seating shall comply with Section 1017.4.


This section requires that each assembly area have designated aisles. For aisle accessway requirements, see Section 1028.10. Assembly area aisle accessways between tables and chairs are to comply with the width requirements in Section 1017.4.




1028.9.1 Minimum aisle width. The minimum clear width for aisles shall be as shown:
1. Forty-eight inches (1219 mm) for aisle stairs having seating on each side.

Exception: Thirty-six inches (914 mm) where the aisle serves less than 50 seats.
2. Thirty-six inches (914 mm) for aisle stairs having seating on only one side.
3. Twenty-three inches (584 mm) between an aisle stair handrail or guard and seating where the aisle is subdivided by a handrail.
4. Forty-two inches (1067 mm) for level or ramped aisles having seating on both sides.

Exceptions:
1. Thirty-six inches (914 mm) where the aisle serves less that 50 seats.

2. Thirty inches (762 mm) where the aisle does not serve more than 14 seats.

5. Thirty-six inches (914 mm) for level or ramped aisles having seating on only one side.

Exceptions:
1. Thirty inches (762 mm) where the aisle does not serve more than 14 seats.

2. Twenty-three inches (584 mm) between an aisle stair handrail and seating where an aisle does not serve more than five rows on one side.




The clear widths of aisles and other means of egress established by the formulas given in Section 1028.6 must not be less than the minimum width requirements of this section. The development of minimum width requirements is based on the association of aisle capacity with the path of exit travel as influenced by the different features of aisle construction. The purpose is to create an aisle system that would provide an even flow of occupant egress. The minimum width of the aisles is also based on an anticipated movement of people in two directions. The exceptions are only intended to be applicable to the item directly above.

1028.9.2 Aisle width. The aisle width shall provide sufficient egress capacity for the number of persons accommodated by the catchment area served by the aisle. The catchment area served by an aisle is that portion of the total space that is served by that section of the aisle. In establishing catchment areas, the assumption shall be made that there is a balanced use of all means of egress, with the number of persons in proportion to egress capacity.


The determination of required aisle and aisle accessway width is a function of the occupant load. In calculating the required widths, the assumption is that in a system or network of aisles and aisle accessways serving an occupied area, people will normally exit the area in a way that will distribute the occupant load throughout the system in proportion to the egress capacity of the aisles and aisle accessways. Each aisle and aisle accessway would take its tributary share (catchment area) of the total occupant load (see Figure 1028.9.2).

In addition to the provisions in this section, the requirement for the capacity of the main exit and other exits must also be considered (see Section 1028.2). While this section assumes an equal distribution, Section 1028.2 requires that where the facility has a main exit, the main exit and the access thereto must be capable of handling 50 percent of the occupant load.





Figure 1028.9.2 TYPICAL AISLE CATCHMENTS

1028.9.3 Converging aisles. Where aisles converge to form a single path of egress travel, the required egress capacity of that path shall not be less than the combined required capacity of the converging aisles.


Where one or more aisles or aisle accessways meet to form a single path of egress travel, that path must be sized to handle the combined occupant capacity of the converging aisles and aisle accessways (see Figure 1028.9.3). The reason for this requirement is to maintain the natural pace of travel all the way through the aisle accessways or aisles to the exits and to minimize the queuing of occupants.

This section requires combining the required occupant capacity of converging aisles and aisle accessways, but not necessarily the required widths. For example, if two 48-inch (1219 mm) aisles converge, the result need not be a 96-inch (2438 mm) aisle unless the 48-inch (1219 mm) width of the aisles is required based on the requirements of Section 1028.6 for the actual occupant load served. However, if the 48-inch (1219 mm) width is not based on the occupant load but is required to comply with the minimum aisle width requirements of Section 1028.9.1, the resulting aisle width must be sized for the total occupant load served by the converging aisles, as determined by Section 1028.6, but not less than the minimum widths of Section 1028.9.1.





For SI: 1 inch = 25.4 mm.


Figure 1028.9.3 COMPUTATION OF EXIT PASSAGE FOR CONVERGING AISLES

1028.9.4 Uniform width. Those portions of aisles, where egress is possible in either of two directions, shall be uniform in required width.


Aisles that connect or lead to opposite exits must be of uniform width throughout their entire length to allow for exit travel in two directions without creating a traffic bottleneck (see Figure 1028.9.4).





Figure 1028.9.4 AISLE WITH OPPOSITE EXITS

1028.9.5 Assembly aisle termination. Each end of an aisle shall terminate at cross aisle, foyer, doorway, vomitory or concourse having access to an exit.

Exceptions:
1. Dead-end aisles shall not be greater than 20 feet (6096 mm) in length.
2. Dead-end aisles longer than 20 feet (6096 mm) are permitted where seats beyond the 20-foot (6096 mm) dead-end aisle are no more than 24 seats from another aisle, measured along a row of seats having a minimum clear width of 12 inches (305 mm) plus 0.6 inch (15.2 mm) for each additional seat above seven in the row.
3. For smoke-protected assembly seating, the dead-end aisle length of vertical aisles shall not exceed a distance of 21 rows.
4. For smoke-protected assembly seating, a longer dead-end aisle is permitted where seats beyond the 21-row dead-end aisle are not more than 40 seats from another aisle, measured along a row of seats having an aisle accessway with a minimum clear width of 12 inches (305 mm) plus 0.3 inch (7.6 mm) for each additional seat above seven in the row.


Both ends of a cross aisle must terminate at either an intersecting aisle, a foyer, a doorway or a vomitory (lane) that gives access to an exit(s). Each exception allows an aisle to have a dead-end of limited length. Exceptions 1 and 2 address dead end aisles in assembly seating areas with or without smoke protection. Exceptions 3 and 4 address dead-end aisles only in smoke-protected assembly seating. In accordance with Exception 1, dead-end aisles (similar to corridors and passageways) that terminate at one end of a cross aisle or at a foyer, doorway or vomitory must not be more than 20 feet (6096 mm) in length. The intent of the row width requirements in the exceptions is to provide sufficient clear width between rows of seating to allow the occupants in times of emergency to pass quickly from a dead-end aisle to the aisle at the opposite end. In Exception 2, the 0.6-inch (15 mm) increase beyond seven seats is consistent with the minimum width determined in accordance with Section 1028.10.2 for single access rows. The code recognizes that one dead-end aisle may not be usable, thus creating a single access row condition. Exceptions 3 and 4 allow longer dead-end aisles for smoke-protected assembly seating that complies with Sections 1028.6.2.1 through 1028.6.2.3 or Section 1028.6.3 (see Figure 1025.9.5).

The overall purpose of this section is to provide aisle/seating arrangements that would allow the occupants to seek safe and rapid passage to exits in case of fire or other emergency.





Figure 1028.9.5 TYPICAL BALCONY ARRANGEMENT

1028.9.6 Assembly aisle obstructions. There shall be no obstructions in the required width of aisles except for handrails as provided in Section 1028.13.


Except for handrails, aisles are required to be clear of any obstructions so that the full width is available for egress purposes. Handrails are allowed to project into the required aisle width in the same manner as handrail projections in stairways.

1028.10 Clear width of aisle accessways serving seating. Where seating rows have 14 or fewer seats, the minimum clear aisle accessway width shall not be less than 12 inches (305 mm) measured as the clear horizontal distance from the back of the row ahead and the nearest projection of the row behind. Where chairs have automatic or self-rising seats, the measurement shall be made with seats in the raised position. Where any chair in the row does not have an automatic or self-rising seat, the measurements shall be made with the seat in the down position. For seats with folding tablet arms, row spacing shall be determined with the tablet arm in the used position.

Exception: For seats with folding tablet arms, row spacing is permitted to be determined with the tablet arm in the stored position where the tablet arm when raised manually to vertical position in one motion automatically returns to the stored position by force of gravity.


The requirements of this section are applicable to theater-type seating arrangements. This includes both "continental" and "traditional" seating arrangements. Theater-type seating is characterized by a number of seats arranged side by side and in rows. In this type of seating arrangement, the potential exists for a large number of occupants to be present in a confined environment where the ability of the occupants to move is limited. In order to egress, people are required to move within a row before reaching an aisle or aisle accessway, and the aisle or aisle accessway also limits movement toward an exit. To provide adequate passage between rows of seats, this section requires that the clear width between the back of a row to the nearest projection of the seating immediately behind must be at least 12 inches (305 mm) (see Figure 1028.10). Where chairs are manufactured with automatic or self-lifting seats, the minimum width requirement may be measured with the seats in a raised position. These are commonly used in college lecture halls. When tablet arm chairs are used, the required width is to be determined with the tablet arm in its usable position. The exception allows for folding arms that fall back into the stored position when a person rises out of the seat. Even if someone has raised the writing surface on both sides, when students egress down the row they would at most encounter one additional tablet to move out of the way. With these types of arms, the aisle accessway can be measured for the seat or arm as indicated in Figure 1028.10.

With respect to self-rising seats, ASTM F 851 provides one method of determining acceptability.





For SI: 1 inch = 25.4 mm.


Figure 1028.10 MINIMUM REQUIRED ROW WIDTH CLEARANCE FOR AISLE ACCESSWAYS




1028.10.1 Dual access. For rows of seating served by aisles or doorways at both ends, there shall not be more than 100 seats per row. The minimum clear width of 12 inches (305 mm) between rows shall be increased by 0.3 inch (7.6 mm) for every additional seat beyond 14 seats, but the minimum clear width is not required to exceed 22 inches (559 mm).

Exception: For smoke-protected assembly seating, the row length limits for a 12-inch-wide (305 mm) aisle accessway, beyond which the aisle accessway minimum clear width shall be increased, are in Table 1028.10.1.


Where rows of seating are served by aisles or doorways located at both ends of the path of row travel, the number of seats that may be used in a row may be up to, but not more than, 100 (continental seating) and the minimum required clear width aisle accessway of 12 inches (305 mm) between rows of seats must be increased by 0.3 inch (8 mm) for every additional seat beyond 14, but not more than a total of 22 inches (559 mm) (see Figure 1028.10.1). For example, in a row of 24 seats, the minimum clear width would compute to 15 inches (381 mm) [12 + (0.3 × 10)]. For a row of 34 seats, a clear width of 18 inches (457 mm) would be required. Increases in the clear width between rows of seats would occur up to a row of 46 seats. From 47 to 100 seats, a maximum clear width between rows of 22 inches (559 mm) would apply.

Since the row is to provide access to an aisle in both directions, the minimum width applies to the entire length of the row aisle accessway.

The exception allows more seats in a row with the minimum 12-inch (305 mm) seat spacing since safe egress time is extended for this condition.

For additional aisle accessway width requirements when one of the means of egress at the end of the single access row is through a dual access row, see Section 1028.8.1.





For SI: 1 inch = 25.4 mm.


Figure 1028.10.1 TYPICAL DUAL ACCESS ROW—MINIMUM AISLE ACCESSWAY WIDTH



TABLE 1028.10.1 SMOKE-PROTECTED ASSEMBLY AISLE ACCESSWAYS

TOTAL NUMBER OF SEATS IN THE SMOKE-PROTECTED ASSEMBLY OCCUPANCY
MAXIMUM NUMBER OF SEATS PER ROW PERMITTED TO HAVE A MINIMUM 12-INCH CLEAR WIDTH AISLE ACCESSWAY
Aisle or doorway at both ends of row
Aisle or doorway at one end of row only
Less than 4,000
14
7
4,000
15
7
7,000
16
8
10,000
17
8
13,000
18
9
16,000
19
9
19,000
20
10
22,000 and greater
21
11


For SI: 1 inch = 25.4 mm.



Table 1028.10.1 recognizes the increased egress time available in smoke-protected assembly seating areas. Therefore, the table permits greater lengths of rows that have the minimum 12 inches (305 mm) of clear width. When a row exceeds the lengths identified in the table, the row width is to be increased in accordance with Section 1028.10.1 [0.3 inch (8 mm) per additional seat] for dual access rows and Section 1028.10.2 [0.6 inch (15 mm) per additional seat] for single access rows. The requirements of this table are based on the total number of seats contained within the assembly space.

1028.10.2 Single access. For rows of seating served by an aisle or doorway at only one end of the row, the minimum clear width of 12 inches (305 mm) between rows shall be increased by 0.6 inch (15.2 mm) for every additional seat beyond seven seats, but the minimum clear width is not required to exceed 22 inches (559 mm).

Exception: For smoke-protected assembly seating, the row length limits for a 12-inch-wide (305 mm) aisle accessway, beyond which the aisle accessway minimum clear width shall be increased, are in Table 1028.10.1.


Where rows of seating are served by an aisle or doorway at only one end of a row, the minimum clear width of 12 inches (305 mm) between rows of seats must be increased by 0.6 inch (15 mm) for every additional seat beyond seven, but not more than a total of 22 inches (559 mm) (see Figure 1028.10.2). While this section does not specify the maximum number of seats permitted in a row, the 30-foot (9144 mm) common path of travel limitation (see Section 1028.8) essentially restricts the single access row to approximately 20 seats, based on an 18-inch (457 mm) width per seat. A row of 12 seats would compute to a required minimum width of 15 inches [12 + (0.5 × 5)]. Similarly, a row of 17 seats would require a clear width of 18 inches (457 mm) and so on. Since dual access is not provided, incremental increases would be permitted in the aisle accessway width as shown in Figure 1028.10.2. Incremental increases in the required width would occur up to the maximum number of seats, which is determined by the 30-foot (9144 mm) dead-end limitation.

The reason for increasing the row accessway widths incrementally with increases in the number of seats per row is to provide more efficient passage for the occupants who are using the aisle accessway. As a practical matter, where dual-access (see Section 1028.10.1) and single-access seating arrangements are used together, the largest computed clear width dimension would normally be applied by the designer to both arrangements so that the rows of seats will be in alignment. For additional aisle accessway width requirements when one of the means of egress at the end of the single access row is through a dual access row, see Section 1028.10.1.





For SI: 1 inch = 25.4 mm.


Figure 1028.10.2 TYPICAL SINGLE ACCESS ROW—MINIMUM AISLE ACCESSWAY WIDTH

1028.11 Assembly aisle walking surfaces. Aisles with a slope not exceeding one unit vertical in eight units horizontal (12.5-percent slope) shall consist of a ramp having a slip-resistant walking surface. Aisles with a slope exceeding one unit vertical in eight units horizontal (12.5-percent slope) shall consist of a series of risers and treads that extends across the full width of aisles and complies with Sections 1028.11.1 through 1028.11.3.


Assembly facilities such as theaters and auditoriums often require sloping or stepped floors to provide seated occupants with preferred sightlines for viewing presentations (for sightlines for wheelchair spaces, see Section 1108.2). Aisles must, therefore, be designed to accommodate the changing elevations of the floor in such a manner that the path of travel will allow occupants to leave the area at a rapid pace with minimal possibilities for stumbling or falling during times of emergency.

This section requires that aisles with a gradient of one unit vertical and eight units horizontal (12.5 percent slope) or less must consist of a ramp with a slip-resistant surface. Aisles with a gradient exceeding one unit vertical and eight units horizontal (12.5-percent slope) must consist of a series of treads and risers that comply with the requirements of Sections 1028.11.1 through 1028.11.3. Note that ramps that serve as part of an accessible route to and from accessible wheelchair spaces must comply with the more restrictive requirements for ramps in Section 1010 (see Section 1010.1, Exception 1).

While not specifically indicated for stepped aisles, such floor surfaces must also be slip resistant in accordance with Section 1003.4. Field testing and uniform enforcement of the concept of slip resistance is not practical. One method used to establish slip resistance is that the static coefficient of friction between leather [Type 1 (Vegetable Tanned) of Federal Specification KK-L-165C] and the floor surface is greater than 0.5. Laboratory test procedures can determine the static coefficient of resistance.

What must be recognized here is that stepped aisles are part of the floor construction and are intended to provide horizontal egress. Tread and riser construction for this purpose should not be compared to the requirements for treads and risers in conventional stairways that serve as means of vertical egress. Sometimes, because of design considerations, the gradient of an aisle is required to change from a level floor to a ramp and then to steps. In cases where there is no uniformity in the path of travel, occupants tend to be considerably more cautious, particularly in the use of stepped aisles, than they would normally be in the use of conventional stairways.




1028.11.1 Treads. Tread depths shall be a minimum of 11 inches (279 mm) and shall have dimensional uniformity.

Exception: The tolerance between adjacent treads shall not exceed 3/16 inch (4.8 mm).


Depths of treads are not to be less than 11 inches (279 mm) and uniform throughout each flight, except that a variance of not more than 3/16 inch (4.8 mm) is permitted between adjacent treads to accommodate variations in construction. While this provision is the same as the limiting dimension for treads in interior stairways (see Section 1009.3), it rarely applies in the construction of stepped aisles. A more common form of stepped aisle construction is to provide a tread depth equal to the back-to-back distance between rows of seats. This way the treads can be extended across the full length of the row and serve as a supporting platform for the seats. Other arrangements might require two treads between rows of seats.

In theaters, for example, the back-to-back distance between rows of fixed seats usually ranges some-where between 3 and 4 feet (914 and 1219 mm), depending on seat style and seat dimensions as well as the ease of passage between the rows (see Figure 1028.11.1). The selection of single-tread or two-tread construction between rows of seats depends on the gradient and suitable riser height (see Section 1028.11.2), as needed for sightlines.

In comparing this section with Section 1028.11.2, it is significant to note the emphasis placed on the tread dimension. While not desirable, the code permits riser heights to deviate; however, tread dimensions must not vary beyond the 0.188-inch (4.8 mm) tolerance.





For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.


Figure 1028.11.1 TYPICAL SEATING PLATFORMS ALSO USED AS STEPPING AISLES

1028.11.2 Risers. Where the gradient of aisle stairs is to be the same as the gradient of adjoining seating areas, the riser height shall not be less than 4 inches (102 mm) nor more than 8 inches (203 mm) and shall be uniform within each flight.

Exceptions:
1. Riser height nonuniformity shall be limited to the extent necessitated by changes in the gradient of the adjoining seating area to maintain adequate sightlines. Where nonuniformities exceed 0.188 inch (4.8 mm) between adjacent risers, the exact location of such nonuniformities shall be indicated with a distinctive marking stripe on each tread at the nosing or leading edge adjacent to the nonuniform risers. Such stripe shall be a minimum of 1 inch (25 mm), and a maximum of 2 inches (51 mm), wide. The edge marking stripe shall be distinctively different from the contrasting marking stripe.
2. Riser heights not exceeding 9 inches (229 mm) shall be permitted where they are necessitated by the slope of the adjacent seating areas to maintain sightlines.


In stepped aisles where the gradient of the aisle is the same as the gradient of the adjoining seating area, riser heights are not to be less than 4 inches (102 mm) nor more than 8 inches (203 mm) (see Figure 1028.11.2). For the safety of the occupants, risers should have uniform heights, where possible, throughout each flight of steps. However, nonuniformity of riser heights is permitted in cases where changes to the gradient in the adjoining seating area are required because of sightlines and other seating layout considerations.

Where variations in height exceed 3/16 inch (4.8 mm) between adjacent risers, a distinctive marking stripe between 1 and 2 inches (25 and 51 mm) wide is to be located on the nosings of each tread where the variations occur as a visual warning to the occupants to be cautious. Frequently, this is done with "runway" lights. Note that this stripe must be different from the tread contrast marking stripes required in Section 1028.11.3. These stripes must be visible in lighted conditions; therefore, these stripes are not required to comply with the provisions for luminous tread markings in Section 1024.

In comparing this section with Section 1028.11.1, it is significant to note the emphasis placed on the tread dimension. While not desirable, the code permits riser heights to deviate; however, Section 1028.11.1 does not permit tread dimensions to vary beyond the 3/16-inch (4.8 mm) tolerance.





For SI: 1 inch = 25.4 mm.


Figure 1028.11.2 TYPICAL RISER CONSTRUCTION IN STEPPED AISLES

1028.11.3 Tread contrasting marking stripe. A contrasting marking stripe shall be provided on each tread at the nosing or leading edge such that the location of each tread is readily apparent when viewed in descent. Such stripe shall be a minimum of 1 inch (25 mm), and a maximum of 2 inches (51 mm), wide.

Exception: The contrasting marking stripe is permitted to be omitted where tread surfaces are such that the location of each tread is readily apparent when viewed in descent.


The exception provides for the omission of the contrasting marking stripe where the tread is readily apparent such as when aisle stair treads are provided with a roughened metal nosing strip or where lighted nosings occur. In this situation, the user is aware of the treads without the marking stripe. This stripe must be different from the marking stripe required for nonuniform risers in Section 1028.11.2, Exception 1.

These stripes must be visible in lighted conditions; therefore, these stripes are not required to comply with the provisions for luminous tread markings in Section 1024.

1028.12 Seat stability. In places of assembly, the seats shall be securely fastened to the floor.

Exceptions:

1. In places of assembly or portions thereof without ramped or tiered floors for seating and with 200 or fewer seats, the seats shall not be required to be fastened to the floor.
2. In places of assembly or portions thereof with seating at tables and without ramped or tiered floors for seating, the seats shall not be required to be fastened to the floor.
3. In places of assembly or portions thereof without ramped or tiered floors for seating and with greater than 200 seats, the seats shall be fastened together in groups of not less than three or the seats shall be securely fastened to the floor.
4. In places of assembly where flexibility of the seating arrangement is an integral part of the design and function of the space and seating is on tiered levels, a maximum of 200 seats shall not be required to be fastened to the floor. Plans showing seating, tiers and aisles shall be submitted for approval.
5. Groups of seats within a place of assembly separated from other seating by railings, guards, partial height walls or similar barriers with level floors and having no more than 14 seats per group shall not be required to be fastened to the floor.
6. Seats intended for musicians or other performers and separated by railings, guards, partial height walls or similar barriers shall not be required to be fastened to the floor.


The purpose of this section is to require that assembly seating be fastened to the floor where it would be a significant hazard if loose and subject to tipping over. The exceptions allow loose assembly seating for situations where the hazard is lower, such as floors where ramped or tiered seating is not used, where no more than 200 seats are used and for box seating arrangements where a limited number of seats are within railings, guards or partial height walls.

1028.13 Handrails. Ramped aisles having a slope exceeding one unit vertical in 15 units horizontal (6.7-percent slope) and aisle stairs shall be provided with handrails located either at the side or within the aisle width.

Exceptions:

1. Handrails are not required for ramped aisles having a gradient no greater than one unit vertical in eight units horizontal (12.5-percent slope) and seating on both sides.
2. Handrails are not required if, at the side of the aisle, there is a guard that complies with the graspability requirements of handrails.
3. Handrail extensions are not required at the top and bottom of aisle stairs and aisle ramp runs to permit crossovers within the aisles.


For the safety of occupants, handrails must be provided in aisles where ramps exceed a gradient of one unit vertical in 15 units horizontal (6.67-percent slope) (see Figure 1028.13).

Exception 1 omits the handrail requirements where ramped aisles are not steep and seats are on both sides to reduce the fall hazard.

Exception 2 allows handrails to be omitted where there is a guard at the side of the aisle with a top rail that complies with the requirements for handrail graspability (see Section 1012.3). Note that the guard must meet the height and opening requirements specified in Section 1013 or 1028.14, as applicable.

While Section 1028.13.1 does allow for discontinuous handrails, and Exception 3 (as well as Section 1012.6, Exception 2) exempts handrail extensions, the handrail must extend the full run of the aisle stair. Stopping the handrail a couple of risers from the bottom of the stair flight would be considered a code violation.





For SI: 1 inch = 25.4 mm.


Figure 1028.13 TYPICAL RAILING FOR RAMPED AISLES WITH RAILING IN THE AISLE

1028.13.1 Discontinuous handrails. Where there is seating on both sides of the aisle, the handrails shall be discontinuous with gaps or breaks at intervals not exceeding five rows to facilitate access to seating and to permit crossing from one side of the aisle to the other. These gaps or breaks shall have a clear width of at least 22 inches (559 mm) and not greater than 36 inches (914 mm), measured horizontally, and the handrail shall have rounded terminations or bends.


Where aisles have seating on both sides, handrails may be located at the sides of the aisles, but are typically located in the center of the aisle. The width of each section of the subdivided aisle between the handrail and the edge of seating is not to be less than 23 inches (584 mm) (see Section 1028.9.1, Item 3).

For reasons of life safety in fire situations and also as a practical matter in the efficient use of the facility, a handrail down the middle of an aisle should not be continuous along its entire length. Crossovers must be provided by means of gaps or breaks in the handrail installation. Such openings must not be less than 22 inches (559 mm) nor more than 36 inches (914 mm) wide, and must be provided at intervals not exceeding the distance of five rows of seats (see Figure 1028.13.1). All handrail terminations should be designed to have rounded ends or bends to avoid possible injury to the occupants (see Figure 1028.13).





For SI: 1 inch = 25.4 mm.


Figure 1028.13.1 DISCONTINUOUS AISLE HANDRAILS

1028.13.2 Intermediate handrails. Where handrails are provided in the middle of aisle stairs, there shall be an additional intermediate handrail located approximately 12 inches (305 mm) below the main handrail.


Handrail installations down the middle of an aisle must be constructed with intermediate rails located 12 inches (305 mm) below and parallel to main handrails. This is to provide handholds for children, to prevent people from using the handrail like a gym apparatus and possibly injuring themselves and from ducking to get under the rail (see Figure 1028.13).

1028.14 Assembly guards. Assembly guards shall comply with Sections 1028.14.1 through 1028.14.3.


This section establishes the scope of the assembly guard provisions.




1028.14.1 Cross aisles. Cross aisles located more than 30 inches (762 mm) above the floor or grade below shall have guards in accordance with Section 1013.

Where an elevation change of 30 inches (762 mm) or less occurs between a cross aisle and the adjacent floor or grade below, guards not less than 26 inches (660 mm) above the aisle floor shall be provided.

Exception: Where the backs of seats on the front of the cross aisle project 24 inches (610 mm) or more above the adjacent floor of the aisle, a guard need not be provided.


The purpose of this section is to provide for occupant safety with guards along elevated cross aisles. The minimum height of the guard is a function of the cross-aisle elevation above the adjacent floor or grade below [i.e., 42 inches (1067 mm) high with more than a 30-inch (762 mm) drop-off and 26 inches (660 mm) high with a 30-inch (762 mm) or less drop-off]. When the backs of the seats adjacent to the cross aisle are a minimum of 24 inches (610 mm) above the floor level of the cross aisle, they will serve as the guard (see Figure 1028.14.2 for an illustration of the requirements in this section).





For SI: 1 inch = 25.4 mm.


Figure 1028.14.2 TYPICAL BALCONY GUARDS AT FASCIA

1028.14.2 Sightline-constrained guard heights. Unless subject to the requirements of Section 1028.14.3, a fascia or railing system in accordance with the guard requirements of Section 1013 and having a minimum height of 26 inches (660 mm) shall be provided where the floor or footboard elevation is more than 30 inches (762 mm) above the floor or grade below and the fascia or railing would otherwise interfere with the sightlines of immediately adjacent seating. At bleachers, a guard must be provided where required by ICC 300.


This section specifies a height of 26 inches (660 mm) for guards within assembly seating areas other than at the end of aisles where a vertical 36-inch (914 mm) height is required. This is to provide a reasonable degree of safety while providing for sightlines within the viewing area. The guard opening configuration must comply with Section 1013.3 (see Figure 1028.14.2 for an illustration of the requirements in this section).

1028.14.3 Guards at the end of aisles. A fascia or railing system complying with the guard requirements of Section 1013 shall be provided for the full width of the aisle where the foot of the aisle is more than 30 inches (762 mm) above the floor or grade below. The fascia or railing shall be a minimum of 36 inches (914 mm) high and shall provide a minimum 42 inches (1067 mm) measured diagonally between the top of the rail and the nosing of the nearest tread.


This section applies only at the end of aisles where the foot (the lower end) of the aisle is greater than 30 inches (762 mm) above the adjacent floor or grade below. The guard must satisfy both of the specified height requirements to provide safety for persons at the end of the aisle. The 36-inch (914 mm) minimum height is measured from the floor vertically to the top of the guard. The minimum 42-inch (1067 mm) diagonal dimension from the nosing of the nearest stair tread to the top of the fascia or guard is to provide sufficient height for a fall from the nearest stair tread (see Figure 1028.14.2 for an illustration of the requirements in this section).

1028.15 Bench seating. Where bench seating is used, the number of persons shall be based on one person for each 18 inches (457 mm) of length of the bench.


The purpose of this section is to specify the length of bench for each occupant for bench and bleacher seating. This is commonly used to calculate the occupant load of bench or bleacher seating for egress purposes and is not intended to limit any individual to an 18-inch (457 mm) area. This is consistent with the fixed seating occupant loads indicated in Section 1004.7.