INDUSTRY NEWS

Why Does The Fire Alarm Code Change?
Technology continues to serve as a driving force for improvements.

NFPA Journal®, July/August 2007

Each code cycle changes are made to NFPA 72®, National Fire Alarm Code®, and many not involved in the process ask why. Some might answer that no code or standard is perfect, but the real answer is that most codes and standards are living documents.

Technology is rapidly changing, as most of us experience daily when we purchase electronic equipment-a digital camera or computer, for example. The technology that drives the fire alarm market is no different. Anyone who had the opportunity to visit the NFPA World Safety Conference and Exposition® in Boston last month experienced first hand the changes in available fire alarm systems technology. Based on the evidence in the marketplace, the Code will always have difficulty keeping up with new technology because the products change so fast! But technology is only one reason the Code may be changed. Three other factors provide reasons for code changes. The first, of course, is fire experience. The second is how the Code is interpreted and enforced by the users of the document; and last are the installation issues that arise from the Code requirement.

As fires and the fire alarm system performance in those fires are reported, it often becomes evident that the Code must change to help ensure systems will perform under real fire conditions. One such change that began in the 1993 Code and was expanded in the 2007 edition of NFPA 72 is the protection of fire alarm control equipment. In 1993, the Code was changed based on fire reports that showed the fire had attacked the fire alarm control equipment before the system responded to the fire condition. The Technical Committee added the requirement for a smoke detector to be located in the area of the fire alarm control unit; if the environment in that location was unsuitable for a smoke detector, a heat detector in the location would be acceptable.

As the Code was enforced, there was some misinterpretation of what the requirement was meant to accomplish. Some AHJs asked that the room where the fire alarm control unit was installed be protected with smoke detectors spaced in accordance with the Code, which often resulted in many additional detectors for that space. As technology changed, some AHJs asked that a smoke detector be installed everywhere there was an addressable monitor or control module installed. In addition, the Code did not give any recognition to those fire alarm control unit locations that were protected by automatic sprinklers.

As a result of these misinterpretations, numerous proposals were made to the Technical Committee to either eliminate the requirement or refine it with clear, enforceable language.

Using the original premise developed by the fire reports used in 1993, the 2007 edition of the Code now requires the following:

4.4.5* Protection of Fire Alarm System. In areas that are not continuously occupied, automatic smoke detection shall be provided at the location of each fire alarm control unit(s), notification appliance circuit power extenders, and supervising station transmitting equipment to provide notification of fire at that location.

Exception No. 1: Where ambient conditions prohibit installation of automatic smoke detection, automatic heat detection shall be permitted.

Exception No. 2: Fully sprinklered buildings shall not require protection in accordance with 4.4.5.

The Technical Committee has addressed the items that relate to the fire alarm control unit that should be protected. But the committee added additional information in the Annex to advise all users of the Code what the committee's intent was and of other issues to consider. One such issue is whether the environment is unsuitable for an electronic smoke detector. If that is the case, it may be unsuitable for electronic control equipment; so the location should be reevaluated for the fire alarm control unit installation. Also, the Annex specifically states "The term fire alarm control unit does not include equipment such as annunciators and addressable devices."

And, finally, the installation issues caused by the Code requirement were also addressed in the Annex with the advice that "Where the area or room containing the control unit is provided with total smoke-detection coverage, additional smoke detection is not required to protect the control unit.

Where total smoke-detection coverage is not provided, the Code intends that only one smoke detector is required at the control unit even when the area of the room would require more than one detector if installed according to the spacing rules in Chapter 5.

The intent of selective coverage is to address the specific location of the equipment." Additional smoke detector placement guidance is also provided in the Annex.

So in the end, the Code changes based not only on technology but also on our experience as the Code is used. Other changes occur when research provides the necessary information to make changes, and those changes will be discussed in the September/October issue.