Means of Egress - A continuous and unobstructed way of travel from any point in a building or structure to a public way consisting of three separate and distinct parts: (1) the exit access, (2) the exit and (3) the exit discharge,1 or more simply put, the path from a location in the building to the street. This is the definition of means of egress in the NFPA Life Safety Code(LSC) and in the NFPA Fire Code. The definitions in the International Building Code (IBC) and International Fire Code (IFC) are very similar. The continuous and unobstructed portion of the definition is important for obvious reasons and is addressed in requirements within the codes. The IBC does have one significant difference in that it includes travel from any occupied portion of a building or , which implies that unoccupied areas do not have means of egress. This article addresses some of the more interesting or controversial means of egress issues in the LSC over the last decade (as well as in the IBC and IFC), and this subject of egress from areas that are normally unoccupied is the subject of several proposals2 for the next edition of the Code. The committee reports that include the proposed revisions for the 2012 edition of the LSC will be considered by the NFPA membership at the NFPA Conference and Expo in June, 2011, in Boston. The 2012 editions of the IBC and IFC have already been finalized.
Although it appears that the IBC and IFC handle this subject with the definition, one quickly discovers that the problem is similar in all four codes in the fact that defining occupied, unoccupied or normally unoccupied is much harder than it sounds. The IBC and IFC do not define unoccupied or occupied, but they do define occupiable space. That is defined as a room or enclosed space designed for human occupancy in which individuals congregate for amusement, educational or similar purposes, or in which occupants are engaged at labor, and which is equipped with means of egress and light and ventilation facilities meeting the requirements of this code. This implies that if one doesn't provide the means of egress, the space is not an occupiable space and, therefore, is not occupied and, therefore, does not need means of egress. It also implies that if one is engaged in labor, it is in an occupiable space which is, therefore, occupied and requires means of egress, even if that labor is only 10 minutes per year. Also, nothing is mentioned of sleeping or residential types of activities, which would be hard pressed to be considered similar to amusement or educational purposes. It is not the intent to be critical of the definition, only to show that occupied is not easy to define. The Life Safety Code defines "occupiable area" as "an area of a facility occupied by people on a regular basis". The obvious problem here is what is "regular basis"? The Code also defines occupied building3 but that definition is restricted to Section 7.2 Means of Egress Components, and is primarily designed to allow doors to be locked under certain conditions when the building is not considered occupied.
MINIMUM STAIR WIDTH
Starting with the 2006 edition of the Life Safety Code, the minimum exit stair width was increased from 44 inches (1.1 m), to 56 inches (1.4 m), under certain conditions.4 This was a result of reaction subsequent to the World Trade Center disaster regarding counter flow on stairs. Firefighters going up the stairs with equipment, and occupants going down the stairs encountered difficulty with this counterflow.5 The 2006 Code requires that stairs serving a total cumulative occupant load of 2,000 or more people must be a minimum of 56 inches (1.4 m). This will usually mean stairs serving fairly tall buildings. For example, assuming maximum capacity of the stairs, a 44-inch (1.1 m) stair will not hit the 2,000 cumulative occupant load until it serves more than 13 stories.Less densely occupied occupancies, such as residential, would be taller before they hit 2,000 occupants. During the revision process for the 2009 edition of the Life Safety Code, there were proposals to mandate the 56-inch (1.4 m) minimums for all new stairs or for all new stairs in high-rise buildings.3 Those supporting the requirement for all stairs are basing it on the increase in obesity, at least in the United States. There are interesting societal issues in those arguments. Those supporting the requirement for high-rise claim that counter flow is a problem in all high-rise buildings, regardless of cumulative occupant load. These proposals were rejected by the NFPA Means of Egress Committee. Interestingly, the proposals were not resubmitted for the 2012 Edition of the LSC, which is currently in process.
HIGH-RISE BUILDINGS - ADDITIONAL EXIT STAIRWAY
The IBC has taken a different approach on the fire-fighter-civilian counter flow issue. In 403.5.2, the IBC now requires an additional exit stair way in high-rise buildings in excess of 420 ft (130 m) in height (over approximately 40 stories, assuming 10 ft (3 m) per story and 20 ft (6.1 m) for the ground floor), exclusive of apartment buildings. The intent is to allow one stairway to be used solely for firefighting operations, without adversely affecting the required exit capacity needed to egress the building occupants. The code intent is not to require a dedicated fire service stairway. Removal of any stair cannot reduce the required exit capacity needed to egress the building occupants, thus allowing the fire department to take control of the one stair best suited to support their operations for that particular emergency. It will be necessary for the fire department to manage evacuation flow to the remaining stairs. The apartment building exception takes into account the relatively low occupant loads associated with that occupancy, which should not significantly affect the counter flow in the stairways. The exception to the additional exit stairway is to provide occupant evacuation elevators in accordance with the new 3008, which is discussed later in this article.
SLIDING NON BREAK-AWAY DOOR ASSEMBLIES
Over the last few editions of the LSC, there has been an increase in the allowance for using non break-a-way sliding doors. For several years, these have been allowed in business, industrial and storage occupancies for areas with occupant loads of 10 or less, along with other restrictions. In the 2006 Edition, this was expanded to healthcare occupancies for areas with an occupant load of fewer than 10; in the 2009 Edition, it was expanded to allow this in any occupancy with an occupant load of fewer than 10, unless the occupancy chapter prohibits it. No occupancy chapters prohibit the use of this provision.1
There are now similar provisions in the IBC. Paragraph 1008.1.2 states that in other than high-hazard occupancies, manually operated horizontal sliding doors are permitted in a means of egress from a space with an occupant load of 10 people or less. This provision now makes the IBC very close to the provisions in the Life Safety Code. The only notable difference is that the LSC sometimes includes the 10th person and sometimes does not. Not a big issue, but something that should be addressed in the future.
LUMINOUS EGRESS PATH MARKINGS
Both the LSC and IBC now have provisions for photoluminescent or self-luminous exit path markings. The significant difference here is that the LSC has provisions for this, but leaves it up to the occupancy chapters to mandate it and none do at this time. In the IBC, such marking is now required in exit stair enclosures and exit passageways in high-rise buildings that contain assembly, business, educational, institutional, mercantile and hotels. (See 403.5.5and 1024.) The exit path markings must meet specific dimensional criteria, unless the markings are listed in accordance with UL 1994, Luminous Egress Path-Marking Systems.4 Where photoluminescent path markings are used, they must be provided with the minimum means of egress illumination (1-ft candle [10 lux]) for at least one hour prior to the building being occupied. This new code language is meant to ensure that occupants can safely egress a high-rise building via stairways in the event the emergency power fails. Much of this is based on work in New York City and by the U.S. General Services Administration (GSA).6
A significant change in the IBC lies in paragraph 1005.1, where the increase in egress capacity factors allowed for sprinkler-protected buildings has been removed. Regardless of the presence of complete sprinkler protection or not, the exit capacity factor for level means of egress is 0.2 inches/person (5 mm/person) and 0.3 inches/person (7.6 mm/person) for stairs. This is virtually the same as the LSC. This provision in the IBC had been controversial, especially in a building code, since egress is often needed for situations other than fires. Interestingly, the LSC never permitted this and the LSC deals primarily with fires. This has been allowed by the IBC since its inception, based on a similar provision in the former BOCA National Building Code. Although some may argue that the LSC does allow an increase incapacity in health care occupancies, it really does not. It provides a decrease in existing occupancies, if sprinklers are not provided. If they are provided, the egress capacity is the same as all other occupancies. This change in IBC language now makes the IBC consistent with the LSC for determining minimum required egress capacity in most situations. This is a significant move toward compatibility.
DEAD-END CORRIDOR LIMITATIONS
Another significant move toward compatibility is the recent changes in the IBC regarding the permitted length of dead-end corridors in several occupancies. Section 1018.4 has increased the permissible length of dead-end corridors with complete automatic sprinkler protection, per NFPA 13. The limit has been extended to 50-ft (30 m) in educational, mercantile, storage, most residential and some institutional occupancies. The 50-ft (30 m) dead-end allowance was previously limited to business and industrial occupancies. The change was made because the record of sprinkler protection in such buildings did not warrant the limitation. This change in the IBC now makes the IBC consistent with the LSC for increased dead-end lengths in buildings with complete sprinkler protection for most occupancies. However, it should be noted that differences still exist for both dead-end corridors and common paths of travel.
HIGH-RISE BUILDINGS - FIRESERVICE ACCESS ELEVATOR
Something unique to the IBC is anew 403.6.1, which requires that new high-rise buildings with an occupied floor level more than 120 ft (37 m - around 10 to 12 stories) above the lowest level of fire department access must now be provided with at least one elevator specifically designed for fire department use, in accordance with new paragraph 3007. Features of the fire service access elevator include:
- An enclosed elevator hoistway with emergency lighting along its entire height.
- An enclosed elevator lobby at each floor other than the level of exit discharge. The lobby enclosure must be designed asa 1-hr rated smoke barrier with -hr rated labeled draft control doors. The lobby must beat least 150 sq ft (14 m2) with a minimum dimension of 8 ft (2.4 m) and have direct access to an exit enclosure.
- A Class I standpipe connection must be located within the exit enclosure providing direct access from the elevator lobby.
- The elevator must be continuously monitored from the fire command center via an interface system that complies with NFPA 72.
A Type 60/Class 2/Level 1standby source
of power must be provided and sized to accommodate:
- Elevator equipment
- Elevator hoistway lighting
- Machine room ventilation and cooling equipment
- Elevator controller cooling equipment
- Wiring and cables associated with the elevator must be enclosed with 1-hr fire-resistive construction or be 1- hr rated labeled circuit integrity cable (CIC).
The code intent is to facilitate the rapid deployment of firefighters and to provide a protected means for the firefighters to access the fire floor. There are somewhat similar, although more stringent, provisions in some European codes.
OCCUPANT EVACUATION ELEVATORS
The LSC Committee on Means of Egress has been discussing the subject of occupant evacuation elevators for some time. In the 2009 Edition of the LSC, a new Annex B was added. This section provides an annex that the Authority Having Jurisdiction (AHJ) may adopt if they wish. It provides no credit to the elevator, but provides information, available at the time, for making an elevator useful for evacuation prior to the activation of phase 1 emergency recall (smoke detection or firefighter key-operated recall). It is intended to address egress issues in very tall buildings such as are now being built, or recently constructed in the Middle and Far East. It is currently proposed to move this annex note into the body of the LSC for the 2012 edition.
Similarly, in the IBC, new section 3008 provides design criteria for elevators to be used for occupant evacuation during an emergency. This section is not mandatory, but it does provide the building designer with a code-authorized alternative to providing the additional exit stair way for high-rise buildings exceeding 420 ft (128 m) in height (apartment buildings are exempted from the additional stairway requirement). However, if elevators are to be used for occupant self-evacuation, then all passenger elevators for general public use must comply with this section. These elevators are designed to be used by occupants for self-evacuation only in normal elevator operating mode, prior to phase I Emergency recall operation. In general, the same fire protection features required of the fire service access elevator (Section 3007) are applicable to occupant evacuation elevators, plus several additional features. One additional feature of particular note is the prohibition of shunt trips and sprinkler protection being installed in the hoistways and elevator machine rooms associated with these elevators; further, the hoistways must use an approved method to prevent the infiltration of water from the operation of the automatic sprinkler system from entering into the hoistways (i.e., curbs, drains, etc., at door openings).
ELEVATOR LOBBY EGRESS
The LSC has had, for several editions, provisions which require that people must have access to at least one exit from an elevator lobby. This has been an issue in many existing buildings requiring discussions with the AHJ for an equivalency, since it is very common to lock the elevator lobby during off hours in a business occupancy. The 2009 edition of the LSC added a rather long laundry list of items that could be done if it was desirable to lock the elevator lobby. Included in this list in 188.8.131.52.3 are a local switch, sprinklers (with water flow releasing the lock), fire alarm system (including smoke detectors in the lobby), fire alarm activation (other than manual stations) that releases the locks, fail-safe activation and more. It should be noted that this provision does not eliminate the option of the building owner or occupant from having an equivalency from the AHJ. This is just one automatic way of being able to lock the lobby.
James K. Lathrop and Clay Aler are with Koffel Associates, Inc.
- NFPA 101 Life Safety Code National Fire Protection Association, Quincy, MA, 2009.
- NFPA 2012 Annual Revision Cycle Report on Proposals, Volume 2, proposals 101-32, 101-33, 101-34, 101-160, 101-161. National Fire Protection Association, Quincy, MA.
- 2008 Annual Revision Cycle ROP on NFPA 5000; NFPA 101; and NFPA 101 Proposal 101-89a, National Fire Protection Association, Quincy, MA.
- UL 1994, Standard for Luminous Egress Path Marking Systems, Under Writers Laboratories, Northbrook, IL, 2010.
- Averill, J. et al. N CSTAR 1-7: Federal Building and Fire Safety Investigation of the World Trade Center Disaster: Occupant Behavior, Egress, and Emergency Communications. National Institute of Standards and Technology, Gaithersburg, MD. 2005.
- Amy, J. Escape from New York - The Use of photoluminescent Pathway-marking Systems in High-Rise, Emerging Trends, December, 2008. (available from www.fpemag.com.)