Next month at the NFPA Fire Safety Conference & Expo, the 2010 edition of NFPA 72 will be voted on by the National Fire Protection Association membership. The code is on a typical three-year cycle. Similar to most other codes, such as the National Electrical Code (NEC), you expect some changes, especially to accommodate technical advancements and new technology. However, this edition of NFPA 72 has been changed radically and will require some study before you will feel comfortable installing fire alarm systems under its requirements.
The new name—National Fire Alarm and Signaling Code—is a clue to some of the changes. There are three new chapters: Chapter 24, Emergency Communications Systems; Chapter 12, Circuits and Pathways; and Chapter 21, Emergency Control Functions and Interfaces. This month’s column focuses on Chapter 24. I will address Chapters 12 and 21 in future issues.
The new Chapter 24 provides the requirements for Emergency Communications Systems with a total of 20 pages of material, in-cluding the annex. The major difference, of course, is that the code now covers more than just in-building fire emergency voice/alarm communications systems (EVACS) and requires much more in terms of system performance requirements.
For the first time in the code’s history, combining or integrating in-building fire EVACS with other communications systems, such as mass notification, public address and paging systems, is now allowed. In addition, again for the first time, certain mass notification mes-sages can take precedence over a fire alarm signal. Fire alarm signals must take precedence except where mass notification messages, as determined by a risk analysis, are deemed to be a higher priority than fire. A terrorist event is one example.
With the rise of these concerns, people demand actionable information in real time. As a result of that demand, mass notification systems (MNS) have become the norm in all Department of Defense buildings and sites and have begun to make their way into other government and commercial buildings, college campuses and outside environments. Many, if not most, of the MNS have been com-bined or integrated with the in-building fire EVACS.
The technology is now available to ensure that fire alarm or priority mass notification messages (as determined by a risk analysis) will take precedence over any other announcements from non-emergency systems, such as paging from a telephone system or other pub-lic address system. There are speaker systems available that incorporate volume controls and components that will allow occupants to lower or turn off the speakers in their area or office but also are designed to switch the speakers back on to operate at their required power output when the fire alarm system or MNS is actuated. This is one of the safeguards now available to meet the requirements of the code and allow integration of in-building fire emergency voice/alarm communications systems with other communications sys-tems.
These code changes present opportunities for the professional contractor. There is no question that using one speaker system that incorporates all of the requirements of the code instead of a speaker system used with a combination of other communications systems will prove to be financially beneficial for the owner. Not only can there be reduced design, installation and on-going life cycle costs, but regular use of the system for normal paging functions provides an end-to-end test of the audible notification components and circuits. Occupants familiar with use of the system for normal paging also are more likely to be comfortable and proficient in use of the system during an emergency.
In order for the emergency communications system to communicate information properly, it must reproduce the desired messages so that the intended listeners will both hear and understand the message. Intelligible voice messages are a requirement that many de-signers, installers and authorities having jurisdiction have struggled with in earlier editions of the code. The 2010 code defines intelligi-ble as “Capable of being understood; comprehensible; clear.” And it defines intelligibility as “The quality or condition of being intelligi-ble.”
Although the code does not yet require a system to meet a specific level of intelligibility, it provides a new
Annex G, “Speech Intelligibility,” which details the subject of measuring intelligibility levels. Professional contractors should under-stand the importance of having a good distribution of speakers rather than trying to use a higher power output of a few speakers.
This opportunity also presents challenges to the contractor. First, you should have a basic understanding of sound and communications principles. Second, you must become familiar with the importance of message intelligibility.
MOORE, a licensed fire protection engineer, frequent speaker and an expert in the life safety field, is a co-editor of the current National Fire Alarm Code Handbook. Moore is a principal with Hughes Associates Inc. at the Warwick, R.I., office.