The soon-to-be-published 2010 edition of NFPA 72 includes revised and expanded provisions affecting a broader audience than ever before. NFPA’s staff liaison for the code walks us through some of the highlights.
NFPA Journal®, September/October 2009
By Lee F. Richardson
In June, NFPA members at the Technical Meeting in Chicago voted to adopt the 2010 edition of NFPA 72®, National Fire Alarm and Signaling Code®. The new version of the code has taken giant steps in scope and content, changes that will undoubtedly expand the interest base of the code more than any previous edition.
Its creation has also underscored the need to develop further guidance and criteria for visible and audible emergency messaging strategies to address the wide range of situations that emergency communications systems are expected to handle.
Although there will always be future problems to solve, both new and experienced users of the 2010 edition of NFPA 72 will benefit from the extensive efforts of all those who took part in its development. Here are a few critical areas that will be affected by the newly expanded NFPA 72.
For many years, NFPA 72 included provisions for voice message systems used to communicate important information to building occupants during a fire. These systems are required in high-rises and other buildings where complete evacuation may not be possible. In these situations, occupants are instructed to relocate or evacuate only from floors or areas in accordance with the building’s fire emergency response plan.
Recently, however, increased emphasis has been placed on the need to communicate important life safety information in a much broader range of emergencies, including weather emergencies, terrorist threats, and biological, chemical, or nuclear emergencies. The latest edition of NFPA 72 includes requirements and guidance addressing the design and installation of systems used to provide emergency information to people in buildings and in outdoor campus areas, and to selected individuals or groups in various locations, such as during the management of regional emergencies. These are referred to in the industry as mass notification systems.
Mass notification systems are being installed in many U.S. Department of Defense (DoD) buildings throughout the world a result of DoD antiterrorism standards established in 2002. The requirements and guidance for mass notification systems in NFPA 72 were initially developed in response to the needs of those implementing DoD requirements for these systems, including members of the DoD and U.S. military.
Mass notification systems are also being installed at some colleges and universities in response to recent campus violence. In addition, mass notification systems can be used in any number of commercial, industrial, and governmental applications where there is a need to inform or instruct people during an emergency. Any time these systems are installed, the requirements of NFPA 72 apply.
Although it still focuses on fire alarm systems, the new NFPA 72 has been revised and reorganized so its requirements apply more generally, addressing mass notification and other emergency communications systems, as well as fire alarm systems. It is important to note that fire alarm signals are no longer always the highest priority. The requirements of the code have been coordinated, addressing signal and messaging priorities and allowing these systems to function in a more integrated manner. Fire alarm and mass notification systems can be installed as separate systems, but they are more commonly installed as an integrated system to take advantage of the economy of using a single system to perform multiple functions. Code users will find that the 2010 edition embraces this integrated approach.
The 2010 edition has also tackled the related issue of voice intelligibility. Whether they are used for fire or mass notification, systems that provide voice messages must be designed and tested to ensure that messages can be understood.
Revised requirements and extensive new guidance have been added to the code to provide users with a clearer understanding of how to handle this difficult issue. This will be of universal interest to designers, installers, inspection authorities, and owners of any system that provides emergency voice messages.
Signaling for deaf and hard-of-hearing
New provisions for signaling to the deaf and hard-of-hearing will also broaden interest in the 2010 edition of the code. Households in which fire alarm systems or smoke alarms are being installed to signal those with mild to severe hearing loss will be required to provide a low-frequency alarm signal in sleeping rooms. The low-frequency signal must be square wave, having a fundamental frequency of 520 Hz, or provide equivalent waking ability.
A square wave includes multiple odd harmonics that result in a complex tone including a range of frequencies. The low-frequency signal can be produced by a separate notification appliance or by a smoke alarm. In addition, where these installations are intended to signal those with profound hearing loss, a tactile notification appliance—one that, by definition, uses touch or vibration—will be required, in addition to the usual high-intensity strobes located in sleeping rooms.
Beginning January 1, 2014, where commercial fire alarm systems are being installed, audible notification appliances installed to signal any sleeping area will be required to produce the low-frequency audible alarm signal.
Digital alarm communicator systems
Another significant area of interest in the 2010 edition of NFPA 72 involves one of the common means of transmitting signals from a fire alarm system to an offsite monitoring facility: digital alarm communicator systems. The code requires that these systems be connected to the public switched telephone network. In recent years, telephone service has been provided not only by the traditional telephone company but also by other service providers, such as those providing television service or access to the Internet. Revisions to the definition of the term "public switched telephone network" will clarify the type of telephone network permitted to transmit fire alarm signals.
It is recognized that the performance of these telephone networks is not under the control of NFPA 72, but information has been included in the code to explain the performance and features expected of these networks if they are to be used with digital alarm communicator systems.
One of the expected features is that at least eight hours of standby power be provided for field-deployed communications equipment. By contrast, the code requires at least 24 hours of backup power for the fire alarm system itself.
Where fire alarm system signals are sent offsite to a supervising station, these revisions to the code, and the information contained in it, will help system designers, system owners, and inspection authorities to better understand what constitutes a public switched telephone network, and they will help users determine what performance to expect.
Lee F. Richardson is senior electrical engineer at NFPA and staff liaison for NFPA 72.