NFPA Journal®, May/June 2009

By Lee F. Richardson

The next edition of NFPA 72®, National Fire Alarm Code®, will represent the most significant changes to the code since the NFPA detection and signaling documents were combined in 1993. Systems used for weather emergencies, terrorist events, biological, chemical or nuclear emergencies, and other threats will be directly incorporated into the new NFPA 72. Even the name of the code will change, to National Fire Alarm and Signaling Code.

The evolution of the 2010 edition began with the Standards Council’s decision in November 2003 to establish a new project on mass notification systems (MNS) at the request of the U.S. Air Force. A new annex, which provides guidance for the design of MNS, was added to the 2007 edition, along with a number of changes in the requirements to allow fire alarm systems and MNS to work together.

With the establishment of a new technical committee in March 2007, work began on the development of a new chapter on emergency communications systems that will be part of the 2010 code. This new chapter will address requirements for in-building MNS, wide-area MNS, distributed recipient MNS, in-building fire emergency voice/alarm communication systems, and in-building two-way communications systems. Existing chapters, such as the one titled “Fundamentals,” will be modified as needed so that requirements are applicable to emergency communications systems, as well as to fire alarm systems. In addition, two new chapters will be added to address requirements common to both fire alarm and emergency communications systems.

While the scope of the code has clearly expanded beyond provisions for just fire alarm systems, it keeps its core focus on the need to clearly address requirements for those systems. The code will still contain its familiar chapters, but they will be organized differently.

An eye on the research
The 2010 edition will contain significant technical changes based on recent projects of the Fire Protection Research Foundation, work that will have an impact on how the code handles emergency notification to occupants.

Research on fire alarm notification for high-risk groups has provided the basis for changes that will require some notification appliances to use a low-frequency (520 Hz) square wave to more effectively awaken and alert people who have mild to severe hearing loss. The chapter titled “Notification Appliances” will contain a new provision, effective January 1, 2014, that will require audible notification appliances used to provide signals for sleeping areas to produce the new low-frequency signal. The chapter titled “Single- and Multiple-Station Alarms and Household Fire Alarm Systems” will contain a new provision that requires the new low-frequency signal for notification appliances installed in sleeping and guest rooms for those with mild to severe hearing loss. The chapter will also require the use of tactile notification appliances in addition to high-intensity strobes in sleeping and guest rooms for those with profound hearing loss. These provisions will be effective with the adoption of the new edition of the code.

Additionally, research on the intelligibility of fire alarm and emergency communications systems provides the basis for an extensive new annex on speech intelligibility. In many situations, fire alarm and emergency communications systems are required to provide voice instructions and information to occupants during emergencies. The ability of the system to reproduce prerecorded or live voice messages with intelligibility is critical. The new annex will provide detailed guidance for the design, installation, and especially the testing of voice systems to ensure that they are intelligible.

Foundation-supported research into smoke detector spacing for complex beamed and sloped ceilings has also led to changes in the new NFPA 72. The specification of location and spacing requirements for smoke detection in joist and beam ceiling applications has been an historical challenge often resulting in installations that were overly conservative in some applications. The changes in the 2010 code will build on the changes for level beamed ceilings that were introduced in the 2007 edition. The new changes will refine and more clearly address spacing and placement requirements for level beamed ceilings and will add new spacing and placement requirements for sloping ceilings. The new and revised provisions will continue to express beam depths and beam spacing in terms of 10 percent and 40 percent of the ceiling height, respectively, rather than the fixed depth and height specified in previous (2002 and earlier) editions of the code.

Chapters and changes
In addition to the changes that resulted from recent research, the new version of the code contains a number of other significant changes, which are presented here as they appear in the new chapter order.

The “Fundamentals” chapter will include a reorganization of the provisions formerly contained under Subsection 4.4.3, System Functions, and the overall numbering of the chapter will be streamlined by removing redundant section and subsection headings. Significant technical changes will include the following: revision of power supply requirements to include uninterruptable power supplies as a choice of supply source instead of having two independent (primary and secondary) supplies; revisions to more clearly address the priority of fire alarm, MNS, and other signals; and complete revision of the record of completion form.

The new “Circuits and Pathways” chapter will be a combination of old and new requirements. The basic wiring requirements from the current “Fundamentals” chapter will be relocated to the new chapter. A new section on pathway (circuit) class designations will be added. New performance designations for Class A, Class B, Class C, Class D, Class E, and Class X pathways will be provided. (Circuit-style designations are no longer used.) New pathway survivability levels will be established: Level 0, Level 1, Level 2, and Level 3. The new chapter will not require the use of a certain class and level, but will identify the performance designations and survivability levels that can be specified by other chapters or by designers.

The “Inspection, Testing and Maintenance” chapter will retain its current organization and will include the new provisions for the following: automated testing; performance-based inspection and testing; inspection, testing, and maintenance of MNS; and testing of in-building radio communication enhancement systems. The inspection and testing form will be completely revised to provide a more detailed record of testing and to address MNS.
The “Initiating Devices” chapter will include reorganization of the requirements for heat-sensing fire detectors, and the provisions formerly contained in Subsection 5.16, Smoke Detectors for the Control of the Spread of Smoke, will be relocated to the section on smoke-sensing fire detectors. In addition to the changes for smoke detector spacing described under recent research, the chapter will contain the following changes: revision of requirements related to protection of smoke detectors during building construction; elimination of 4-inch (100-millimeter) corner restrictions for smoke detectors; new provisions to allow the installation of smoke detectors close to an object or space they are intended to protect; new provisions addressing the installation and testing of gas detection equipment; and new provisions requiring manual fire alarm boxes to be red.

The “Notification Appliances” chapter, in addition to the new requirements for the low-frequency square wave described under recent research, will include revised provisions for voice intelligibility using a new term: “acoustically distinguishable space.” The code will require the system designer to identify these spaces and to determine if they require voice intelligibility.

The new “Emergency Control Functions” chapter will contain the provisions formerly found in Subsection 6.16, Protected Premises Fire Safety Functions. New subsections on first responder use of elevators and elevators for occupant-controlled evacuation have been added to correlate with the 2009 edition of NFPA 101®, Life Safety Code®, Annex B, and NFPA 5000®, Building Construction and Safety Code®, Annex E.

The “Protected Premises Fire Alarm Systems” chapter will retain most of its current organization. The requirements for circuit designations (circuit class and style) will be streamlined with reference to the “Circuits and Pathways” chapter, which provides a menu of designations. New provisions will be included for non-fire alarm equipment in combination systems. The requirements for emergency voice/alarm communications systems and two-way communications service, including two-way telephone, have been relocated to the “Emergency Communications Systems” chapter. Requirements for fire safety control functions are now contained in the “Emergency Control Functions” chapter.

The “Emergency Communications Systems” chapter will, in addition to providing installation and performance requirements for different types of emergency communications systems, contain new provisions for textual visible notification appliances (message displays) for in-building MNS; public address systems that interface with fire alarm systems; high-powered speaker arrays in wide-area MNS; in-building radio communication enhancement systems; two-way communications systems for areas of refuge (area or rescue assistance); and risk analysis requirements for the design of MNS.

The “Supervising Station Alarm System” chapter will be reorganized to delete four subsections addressing legacy technologies no longer being installed: active multiplex transmission systems; McCulloh systems; directly connected noncoded systems; and private microwave radio systems. The current Subsection 8.6.4, Other Transmission Technologies, will be the first communications method addressed, followed by digital alarm communications systems and radio systems. Significant technical changes will include new provisions for the qualification of supervising station operators, the details of which are located in the “Fundamentals” chapter, and indication of remote station service, which will require owners of systems monitored by a remote supervising station to provide annual documentation identifying the party responsible for inspecting, testing, and maintaining the system. Revisions will also be included for requirements in current Subsection 8.6.4.

The “Public Emergency Alarm Reporting Systems” chapter—previously named “Public Fire Alarm Reporting Systems”—will be revised to more clearly address emergencies in general, not just fire, including an allowance for connection to emergency communications systems. The chapter will be reorganized in terms of “wired networks” and “wireless networks,” and will provide a more logical flow of requirements.

The “Single- and Multiple-Station Alarms and Household Fire Alarm Systems” chapter will retain its current organization and will, in addition to the new requirements for the low-frequency square wave and tactile notification appliances described under recent research, include new provisions for wireless interconnected smoke alarms to ensure their wireless performance; new allowances for managed facility voice networks to be used with digital alarm communications systems for household fire alarm systems; elimination of 4-inch (100-millimeter) corner restrictions for smoke alarms; new restrictions on the placement of smoke alarms in proximity to cooking appliances; and new provisions for smoke alarms to comply with provisions in the “Initiating Devices” chapter for smoke detection in joist and beam ceiling applications.

The breadth and depth of the changes will provide NFPA 72 with a new, broader scope, and will also help the code prepare for future changes. In their developmental stages, the new chapters were added at the end of the code, which served as a temporary residence. After giving thoughtful consideration to the overall code organization—and recognizing that reassignment of chapter numbers every time a new chapter is added can be vexing to users—a new structure was devised. The new organization will contain 29 chapters, including several reserved chapters, allowing for future chapters to be added in a logical order without disrupting the numbering of existing chapters.

Lee F. Richardson is senior electrical engineer at NFPA and staff liaison for NFPA 72.

SIDEBAR
Nitman Released

As this issue of NFPA Journal went to press, two NITMAMs—notices of intent to make a motion—had been received for discussion at the technical meeting in June. One proposes to change the required testing frequency for household fire alarm systems from every three years to every year. The other deals with an issue for the cable industry concerning the transmission of signals from a protected-premises fire alarm system to a supervising station. At issue is the question of whether IP network-based telephone service can be used to transmit fire alarm signals using existing digital alarm communication systems. These systems traditionally use the public switched telephone network—that is, regular telephone lines—to transmit the signals. This is also the subject of a task group working on a potential tentative interim amendment (TIA) to address this issue.

SIDEBAR
Smoke detection: Photoelectric, ionization, or both?

Both, it turns out, if you want more protection. But the new NFPA 72 says that either is enough, in most situations, to meet the minimum requirement of the code.

What kind of smoke alarm technology to choose—photoelectric or ionization—has been the subject of debate for some time. The 2010 edition of NFPA 72 provides updated guidance on the subject based on recommendations made by a task group of the NFPA committee responsible for smoke alarms. The task group evaluated the data currently available from scientifically based testing of smoke alarm response to both flaming and smoldering fires, and recommends the use of both technologies (either as separate or combination units) for those who desire a higher level of protection than required by the code.

Photoelectric detection technology is generally more responsive to fires that begin with a long period of smoldering, and ionization detection is generally more responsive to flaming fires. The committee suggests that "protection beyond the minimum provisions of the code using both technologies should be considered for situations involving individuals who are not capable of self rescue or who might need additional time for escape. These situations might include families where extra time is needed to awaken or assist others." This non-mandatory recommendation will now appear in new annex material, along with an explanation of the issues regarding the two smoke detection technologies. However, this addition does not change the current minimum requirements.

"The current committee consensus is that neither technology offers an advantage over the other for nonspecific fires, and that the minimum requirements of the code of using either technology are adequate for most individuals who are not intimate with the fire and are capable of self rescue," says Lee Richardson, senior electrical engineer at NFPA and staff liaison for NFPA 72.

It is important to note that the conclusions reached by the committee assume that smoke alarm installations are compliant with the latest edition of NFPA 72, which requires smoke alarms inside all sleeping rooms, outside every sleeping area, and on every level of the home. Homes that are not equipped with smoke alarms in these locations should strongly consider following these minimum requirements regardless of the type of detection used.

Smoke alarms are sometime disabled by homeowners due to repeated nuisance alarms from cooking activities. The 2010 edition of NFPA 72 will include additional restrictions (exclusion areas) on the placement of smoke alarms near cooking appliances. These smoke alarm exclusion areas are explained fully in the non-mandatory annex of the code, which also contains further information on nuisance alarm issues.

The technical committee will continue to evaluate new information on smoke alarm performance as it becomes available.

— Lisa Nadile