Dust Explosions - A Solvable Problem

Issue 13: Significant Changes to Means of Egress in the 2006 International Building Code

By Kimberly Paarlberg

The "Means of Egress" is the path that people follow to leave a building in an emergency situation. The people that use the means of egress include both able-bodied people who can self-evacuate, and persons with disabilities or impairments who may require assistance.

The means of egress may be the same route that occupants used to get into the building, but that is not always the case. The means of egress consists of three parts: exit access, exit and exit discharge. The means of egress requirements in the International Building Code1 (IBC) are found in Chapter 10. The chapter organization reflects the three-part system. These same requirements are repeated in Chapter 10 of the International Fire Code2 (IFC).

The "International Codes" are developed through a public hearing process on a three-year cycle. The code books provide an indication of changes from the previous edition by using a line in the margin. An arrow in the margin indicates that a section has been deleted. If state or city amendments are included in the code, they are typically represented by a double line in the margin or with italicized text.

Changes are made for a variety of reasons: clarification, new technology, coordination between requirements in different chapters or codes, etc. This article identifies the significant changes to means of egress requirements in the 2006 IBC. This discussion follows the general organization of the chapter, not any order of significance.

Ceiling Height
Section 1003.2 The minimum ceiling height throughout the means of egress system was changed from 7 ft. (2.1 m) to 7 ft. 6 in. (2.3 m).

Section 1208.1 requires space that can be occupied to have a minimum ceiling height of 7 ft. 6 in. (2.3 m). This change was made to coordinate between requirements in Chapters 10 and 12. The change does not eliminate the exceptions to the ceiling height requirement that previously existed in Section 1003.2.

 

Calculating Occupant Loads

Section 1004.1 A new exception permits the actual occupant load to be utilized for part or all of the design if approved by the building official. Changes were also made to clarify how to determine the occupant load for a space.

The occupant loads in Table 1004.1.1 are based on the anticipated occupant loads for different functions. Previously, the only options available to designers were to use the table or design for an actual occupant load that is higher than that calculated in the table. The new exception would be permitted on a limited basis. For example, an assembly hanger for large aircraft would use 100 sq. ft. (9.3 m2) per occupant for industrial areas. If the actual load of occupants is much less than this, the code official could approve using the actual occupant load for design for the means of egress system. The occupant load is also used to determine the required number of plumbing fixtures and the sizing of the mechanical system. Another example of using the actual occupant load might be a situation in a school with a gym used for school assemblies. Either the gym would be fully occupied or the school would be fully occupied; both would not be fully occupied at the same time. The code official could approve the table loading for design of the means of egress from both spaces, but allow the actual load for the plumbing fixture count.

Section 1004.2 The maximum increased occupant load has been revised from 5 sq. ft.(0.5 m2) to 7 sq. ft. (0.7 m2) per person.

Concerns for overcrowding of assembly spaces have resulted in lowering the maximum permitted occupant load. This does not eliminate the option for using 5 sq. ft. (0.5 m2) as the occupant load for small standing room areas in assembly spaces (Table 1004.1.1). For example, when determining the occupant load for a nightclub, 15 sq. ft. (1.4 m2) per occupant could be used to determine the occupant load in the general seating area, while 5 sq. ft.

(0.5 m2) per person could be used to determine the occupant load for the dance floor and waiting area. The change for the maximum allowable would limit the design of the space to a maximum occupant load calculated by using 7 sq. ft. (0.7 m2) per person for the entire space.

Section 1004.7 In areas with fixed seating, if portions do not have fixed seats, the occupant load must include both the number of fixed seats and the number of people who might occupy the portions that do not have fixed seats.

Where spaces are left open for wheelchair spaces or spaces are reserved for standing room, these spaces must be counted in the total occupant load of the space along with the fixed seating count.

 

Area of Refuge

Sections 1007.3, 1007.4 and 1007.6.2 An exception was deleted, resulting in a requirement that all accessible spaces must have access to a horizontal exit or area of refuge. The area of refuge must be either within a stair enclosure or in an area immediately adjacent to the stair or an elevator provided with a standby power source.

Previous editions of the IBC allowed for areas of refuge to be eliminated in buildings that were sprinklered throughout. (This was not an exception for accessible means of egress.) The exception recognizes that activation of the sprinkler system would automatically notify the emergency responders as well as confine a fire to the immediate area of origin. The exception was deleted due to concern that the system would not be 100 percent effective. (There has been significant code change activity on this issue in the 2006/2007 revision cycle. More information can be found on the ICC Web site for details, www.iccsafe.org.)

Panic Hardware
Section 1008.1.9 Requirements for panic hardware were expanded.

The threshold for requiring panic hardware for assembly or educational occupancies was decreased from 100 or more people to 50. An exception was also added to clarify that the main exit from an assembly space can use a key-operated locking device under certain conditions. Panic hardware is also required for all high-hazard occupancies and some electrical rooms.

Handrails
Section 1009.10, 1010.8, 1012 – The provisions for handrails have been moved into their own section, similar to guards.

Handrail provisions were previously included in the section on stairways, and were referenced for ramps. The movement to a separate section clarifies the requirements for handrails on ramps.

 

Egress Through Adjacent Spaces

1014.2 – Means of egress can pass through a stockroom serving a mercantile occupancy.

Previously, providing means of egress through a stockroom was prohibited due to concerns that the path may be hard to find or be blocked. Four new provisions allow for the second means of egress to pass through a stock room. The goal is to maintain the path of travel to be obvious and continuously available.

1014.2.1 A new exception allows egress for small tenants through a larger tenant space.

It is not uncommon for a large tenant space, such as a grocery store, to include spaces for small tenants, such as a fast food restaurant or a branch bank. When the tenants have comparable uses, the egress path is discernable and locking devices do not restrict access, the small tenant space can egress through the larger tenant space.

1014.4.2 – Provisions have been added for mercantile occupancies.

Large mercantile occupancies have "merchandise pads" which include aisle access ways that extend to main aisles. Definitions for "merchandise pads" and "aisle" as well as a new section for how this will work in mercantile occupancies have been added to provide for safe evacuation.

Code Changes
The International Codes are "living" documents. This allows them to adjust to changes in technology, design approaches and address new issues as they arise. If any individual or group would be interested in proposing revisions to the code text, forms can be found on the ICC Web site at www.iccsafe.org/cs. ICC code development staff is also available to provide assistance.

Kimberly Paarlberg is with the International Code Council.

1 International Building Code, International Code Council, Falls Church, VA, 2006.
2 International Fire Code, International Code Council, Falls Church, VA, 2006.


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