Emergency Mass Notification and Fire Alarm Systems for All
Both the hearing and those who are hearing impaired must receive the same message, and it must be specific, consistent, certain, clear, and accurate.
- By Wayne D. Moore
- Sep 01, 2010
As stated in the 2007 edition of the National Fire Protection Association's (NFPA) Emergency Evacuation Guide For People with Disabilities,1 "Alternative methods of notification need to be put into the emergency evacuation plans for people with hearing impairments so they can get all of the information they need to evacuate in a timely manner." I would add that these same people need this information to ensure they take the right action in response to any emergency.
The 2010 edition of NFPA 72, National Fire Alarm and Signaling Code®, was adopted by the NFPA membership in June 2009 with an effective date of Aug. 26, 2009. NFPA 72-2010 supersedes all previous editions. With this adoption, a new chapter covering Emergency Communications Systems (ECS) became available for review and use. The reason some jurisdictions, such as Alabama and California, already have adopted this edition of the code is the fact the ECS chapter contains the requirements for Mass Notification Systems (MNS). MNS already has become the norm in all Department of Defense facilities, where all fire alarm systems now have capability to transmit the sound of a human voice and may serve as combination fire alarm systems and MNS. Many large facilities and college campuses also have begun to upgrade their fire alarm system infrastructure to include MNS in every building.
The U.S. Census Bureau has reported nearly 65 million Americans have disabilities in the United States.2 This number represents about one in five Americans. And of this group, the majority includes individuals with impaired hearing. According to the National Association for the Deaf, "In an emergency, deaf and hard of hearing people experience fear and frustration. They may make poor safety decisions since they are uninformed about the nature or scope of the emergency."
It is not technologically feasible to continue to use only visible notification appliances (strobes) to indicate emergencies to people with impaired hearing. Of course, multiple strobe colors probably would lead only to confusion.
Message boards, television monitors, and video display terminals offer acceptable methods to notify the hearing impaired. But as the NFPA guide reminds us, "It is extremely important for people with hearing impairments to know what, if any, visual notification systems are in place. They also need to be aware of which emergencies will activate the visual notification system and which emergencies will not."
As in past editions of the code, the notification requirements include addressing the needs of the hearing impaired. But are we giving mixed signals to those with disabilities?
The ECS design needs to consider the provisions of the Americans with Disabilities Act. Of particular importance, one must recognize that the design of fire alarm strobes (visible notification appliances) intends to alert the hearing-impaired population to evacuate a building. The code requires that, where audible notification is provided, mass-notification systems also must provide visible notification information to serve the hearing impaired. And the MNS also must provide visible notification for high-noise areas. The key word in the requirement: information. Unlike fire alarm strobes -- where the strobes give only one piece of information, namely to "evacuate" -- MNS systems need to provide more information to allow all occupants to understand what the emergency requires them to do. In fact, when the same strobe serves both as fire alarm and an MNS, the strobe housing must have either no lettering or the word "alert" inscribed.
During many non-fire emergencies, it might be more appropriate to have occupants shelter in place. It would therefore be inappropriate to activate the fire alarm strobes when there is a non-fire event requiring a different action other than building evacuation. In addition to the required strobes, the code also permits textual, graphic, or video displays.
Using visual textual messages on scrolling signboards, television screens, computer screens, and personal devices such as cell phones and pagers offers the only truly viable way to provide content rich information and instructions to the hearing impaired. Installing scrolling signboards at every location where the MNS design has placed audible notification appliances is obviously not practical. However, the code does allow the system to notify the hearing impaired to move to a location where they can read a signboard or other textual display.
Any emergency communications system design offers challenges. However, an ECS should offer more than just a technological solution. Rather, to be effective, an ECS should include a structured and rigorously tested procedural/management component. Simply providing information does not guarantee immediate and appropriate response from the target population.
Textual visible information should provide a size and visual quality that is easily read. Many factors influence the readability of textual visible appliances, including the following:
(1) Size and color of the text or graphic
(2) Distance from the point of observation
(3) Observation time
(5) Background luminance
(7) Stray lighting (glare)
(9) Physiological factors
While many the fire alarm equipment manufacturers and the building designers can influence many of these factors, a uniform method of measuring legibility does not currently exist.
The code also permits tactile notification appliances and video display systems that provide alerts and messages to video appliances to supplement mass notification.
Although a very large market exists and a large number of companies to serve that market have taken up the challenge, it seems everyone focuses on the hardware and software needed to deliver messages and no one focuses on the delivered messages.
Obviously, the hardware and software must provide relevant information in a timely fashion that will allow the occupants to take the correct action. George Bernard Shaw stated, "The problem with communication . . . is the illusion that it has been accomplished." Mr. Shaw's statement notwithstanding, research shows message content is one of the most important factors in determining the effectiveness of a warning system.
Erica Kuligowski, one of the researchers in the NIST Technote 1093: Mass Notification Messages: Workshop Proceedings,3 has stated that "Injuries/deaths can occur from using the system improperly -- non/inappropriate response, delays. This occurs when no information is provided, when the notification system fails to operate or cannot be used, or the alarms [sound] on some floors (or buildings) and not in others." She also reported, "Injuries/deaths can occur from using the system improperly, causing non/inappropriate response, or delays." The NIST study found that many systems provided inaccurate information. For example, in one high-rise office building fire, occupants of the fifth floor heard the following message: "There has been a fire reported in the building, please evacuate three floors down and wait for further instructions." The problem with the message was that the fire was on the second floor!
Both the hearing and those who are hearing impaired absolutely must receive the same message. That message must provide the following content:
- Information on the hazard and danger
- Guidance on what people should do
- Description of the location of the risk or hazard
- An idea of when they need to act
- The name of the source of the warning (who is giving it)
The warning style is also crucial. It must be specific, consistent, certain, clear, and accurate. The message may offer information intended to prevent people from continuing an action, such as to not evacuate a building, but shelter in place.
According to the NIST report, warning is a "system," and the system must include obtrusive alerts that offer incentives to respond, such as flashing computer screens and "lights on" in theaters or to wake people up, such as sleeping children and older adults. The "system" must notify those with hearing loss and those under the influence of drugs or alcohol.
"The alerts must also be accompanied with additional cues that may include physical and social cues from the event," said Kuligowski. "Once you have their attention, humans are rational actors that respond to good information. Without this, they will search, mill, delay -- possibly in danger."
What is good information? The NIST reports state there are five main factors: Content, style, channel, frequency, and source. The system can structure the information for all types of technology, new and old. However, message providers must receive better training and preparedness. Better information will create better public and occupant response to the message.
But all of these requirements affect the messages to everyone, including the hearing impaired. And communication represents the life activity most affected by those with hearing disabilities. Among persons with hearing impairment, a wide range of variables can affect the seriousness of the impairment.
For some, their ability to speak may not have adequately developed. Others with hearing impairments speak very clearly. Rarely is a person completely deaf. Useable hearing varies greatly. Severity of hearing loss may vary greatly at different frequencies. Not everyone benefits from hearing aids because they only amplify but do not necessarily make sound clearer. People with hearing impairments will have different education levels. A person who uses American Sign Language (ASL) may or may not have proficiency in English. Some hearing-impaired individuals may have difficulty responding to verbal cues.
All of these factors indicate that designers of emergency communications systems must understand the needs of those with hearing disabilities and ensure the ECS design will accommodate all of the occupants of the building.
1. NFPA Emergency Evacuation Planning Guide for People with Disabilities, June 2007. (www.nfpa.org/assets/files/PDF/forms/EvacuationGuide.pdf)
2. Disabilities Affect One-Fifth of All Americans, Census Brief, U.S. Department of Commerce Economics and Statistics Administration, Bureau of the Census, CENBR/97-5. Issued December 1997.
3. NIST Technote 1093: Mass Notification Messages: Workshop Proceedings. Authors: Kuligowski, Peacock, Averill, and Bukowski. Proceedings published online: http://fire.nist.gov/bfrlpubs/fire09/art011.html.
This article originally appeared in the September 2010 issue of Occupational Health & Safety.