A means of egress from a building has three distinct parts. The strategies and code requirements for signaling to occupants differ for each part. Why should system designs differ? How do code requirements differ? What are the best practices for occupant alerting, notification and communications in the different parts of a means of egress?
What is a means of egress?
To understand the requirements for occupant notification, it is necessary to understand the components of a means of egress . The model building, fire and life safety codes have very specific definitions for the term means of egress and for the three principal components that make up a means of egress. For example, the International Building Code uses the following definition:
MEANS OF EGRESS. A continuous and unobstructed path of vertical and horizontal egress travel from any occupied portion of a building or structure to a public way. A means of egress consists of three separate and distinct parts: the exit access, the exit and the exit discharge.1
Working backwards, the exit discharge is the part between the termination of an exit and a public way. The exit discharge is a path that leads away from a building. The exit is that part of a means of egress that is generally separated from the rest of the building. The separation is provided by fire-rated construction and by protection of any openings using fire-rated doors or dampers as required. An exit provides a protected path from the exit access to the exit discharge. On the level of exit discharge, a door that leads directly from the building to the exit discharge would be the exit, without any required enclosure. The exit access is that part of a means of egress that leads to an exit.
Occupant Notification Requirements
The requirements for occupant notification originate in building, fire and life safety codes. Those codes also refer to the National Fire Alarm and Signaling Code.2 Together, these documents detail the requirements for signaling in the means of egress.
For occupancies or user groups that require occupant notification, signaling is usually required throughout the occupiable parts of the building. For example, in a school or office, it is important that occupant notification be provided for the classrooms, offices, corridors and other occupiable spaces. However, it would not be necessary to have occupant signaling in small closets and crawl spaces that are not intended or suitable for being occupied. An electrical or telecommunications room or a small file room may not normally be occupied, but are occupiable spaces that must have occupant notification.
If occupant notification is required in the occupiable areas, audible and visual signaling in accordance with NFPA 72 will be required. Visible appliances applied per NFPA 72 will also be required in certain spaces that might be used by persons with impaired hearing. The codes and accessibility standards, such as the ADA3, require visible signaling in all public and common use spaces. This includes corridors, toilet rooms, kitchenettes and break rooms.
Classrooms in a school would require, and benefit from, the use of visible signaling. Conference rooms in offices are provided with visible notification appliances if there are employees with hearing impairments or persons from outside the company that might be in the room. However, small offices would not require visible signaling unless occupied by a person with a hearing impairment. Other employee work areas might not require visible signaling to be installed, but might require that the wiring be installed for future accommodation if the space is used by a person with a hearing impairment.3
Once an occupant enters an exit, he or she is in a protected space, separated from the useable building spaces. There is no need, and no code requirement, to operate occupant notification appliances - audible or visible - in an exit. In fact, building, fire and life safety codes and NFPA 72 explicitly state that visible appliances are not required to be installed in exit enclosures and elevators.2, 4
The requirement for installing audible occupant notification appliances in exit enclosures differs where selective signaling is used to partially evacuate or relocate occupants. In that case, the audible appliances (loudspeakers) are provided in the exit enclosures, but are arranged for manual use only; they do not provide any automatic occupant messaging.2 Loudspeakers in an exit enclosure must be on a separate paging zone that permits emergency forces to provide specific and discreet information and directions to persons using the exit.
Code requirements recognize that exit enclosures are safe, protected locations and that occupants in an exit enclosure are in the process of leaving the building or relocating to a safe area. Providing occupant notification appliances, particularly strobe lights, can impair the movement of people in exit enclosures.
Providing tone-only audible signals in an exit enclosure, such as a stair, would be confusing: Does the signal mean persons in the stair must continue to leave the building? Or, does the signal mean they should not be in the exit enclosure? Any person that tries to re-enter from an exit enclosure to a floor of the building will hear and see the notification appliances operating on that floor. In the case of a selective evacuation/relocation system, the notification appliances will not operate on floors where it is safe for occupants tore-enter the building.
Similarly, the codes exempt elevator cars from the requirements for occupant notification appliances. If the elevator is threatened by fire or smoke, the elevator car will be on its way to a safe location - the primary or alternate recall level.5 If the elevator is not threatened, the car will continue to the occupant's chosen destination, where the elevator lobby is safe - at least there would not be any smoke that would have initiated Phase I elevator recall to some other level. Once out of the elevator, if notification appliances are operating, occupants have access to protected exit enclosures. Although elevators are not required to have occupant notification appliances, the codes require that they have two-way communications to an attended location.6
There are no requirements in the model building, fire and life safety codes or in NFPA 72 for occupant notification in the exit discharge. However, some local jurisdictions require audible and/or visible appliances at the exit termination - on the outside near the entrance/exit door. The idea is that the signals provide an indication to persons on the outside of a building that they are not supposed to enter the building. Most jurisdictions do not have that requirement because people will get that same information when they try to access an occupiable part of the building.
Signaling to occupants who are in a means of egress is not a difficult concept once the definitions of exit access, exit and exit discharge are understood. Fire protection engineers are familiar with the definitions and need only apply the coordinated code requirements for audible and visible occupant notification. Still, other disciplines and trades might not be as familiar with the means of egress concepts that drive the occupant notification requirements.
- International Building Code, International Code Council Inc., Washington, DC, 2009.
- NFPA 72, National Fire Alarm and Signaling Code, National Fire Protection Association, Quincy, MA, 2010.
- ADA Standards for Accessible Design, Department of Justice, Washington, DC, 2010. Available at http://www.ada.gov/2010ADAstandards_index.htm.
- NFPA 101, Life Safety Code, National Fire Protection Association, Quincy, MA, 2009.
- Schifiliti, R. Elevator Fire Safety: Elevator Recall and Elevator Power Shutdown. R.P. Schifiliti Associates, Reading, MA, 2010 (available from http://www.rpsa-fire.com.)
- ANSI/ASME A17.1, Safety Code for Elevators and Escalators, American Society of Mechanical Engineers, New York, NY, 2010.