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Let's Get Visible

By Wayne D. Moore | Dec 15, 2014
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As most of you know, the codes and standards for fire alarm and mass notification systems change on a three-year cycle. New technology and more refined occupant needs top the list of reasons for most changes. Over the years, the requirements for visible notification appliances (strobes) have changed to keep up with new research and the development of technology. Initially, strobe lights entered into NFPA 72, National Fire Alarm and Signaling Code, to ensure that deaf and hard-of-hearing building occupants would receive the same alarm/evacuation notification as others in the building.


The strobes initially used for fire alarm system applications consisted of individual units, each with a specific candela output rating designed to comply with the spacing requirements found in Chapter 18 of NFPA 72 2013. The current draw changed as the candela power increased, and the fire alarm system designer had to adjust the system circuitry, power supply capacity and battery size to ensure operational reliability.


The next technology change occurred when manufacturers made units with selective settings on each strobe to allow the system equipment distributors to stock a single unit suitable for any location. The installer chose the proper candela rating for the compartment dimensions and unit spacing. The current draw remained essentially in line with previous strobe lights.


The most recent change for these important alarm notification appliances involves the use of light-emitting diode (LED) strobe lights. These appliances provide a higher operational reliability and a much-reduced current draw.


As strobe technology improves, stakeholders now require more voice/alarm notification systems in new buildings. Since the 2009 edition, the International Building Code requires in-building fire emergency voice/alarm communications systems (EVACS) in all K–12 schools. Although you might think that you only need to use speakers and speaker/strobes throughout the building to comply, you would be wrong.


The required voice systems intend to ensure audibility, intelligibility and visibility of the alarm messages and signals. They also intend to meet the stakeholder’s needs for multiple use in these occupancies. Deaf individuals will get short shrift if the design only uses strobe lights, which only provide one piece of information: “Alarm! Leave the building immediately!” 


The K–12 voice system must give instructions for other emergencies. Thus, the required EVACS now becomes a mass notification system (MNS) to ensure that emergency messages, such as “Lockdown,” “Move to a safe place,” and “Take cover,” are equally distributed to everyone. Strobe lights alone cannot provide detailed information to the deaf and hard-of-hearing.


NFPA 72 2010 introduced the concept of supplemental notification using message boards or flat-screen video. NFPA 72 2013 introduced new requirements to ensure building owners and operators provide the same message to all occupants. In high-noise areas, NFPA 72 2013 still requires the use of strobe lights to provide notification for the deaf and hard-of-hearing.


Chapter 24 states that, in addition to the strobes, textual, graphic or video displays “shall be permitted,” and the visible notification and messages must transmit simultaneously with the audible notification and messages.


The code also allows the textual and graphic messages to provide either supplemental or primary notification, and it provides guidance to ensure the messaging transmits properly. For example, Chapter 18 permits textual and graphical visible appliances “to be used to signal information about fire or other emergency conditions or to direct intended responses to those conditions.” It also provides requirements for character and symbol elements and viewing distance to ensure readability.


A facility’s emergency-response plan must include a template for the messages related to each anticipated emergency scenario to ensure the uniform delivery of information to all building occupants in whichever way they receive the information. The code also recommends care in the location and placement of textual visible appliances to ensure their survivability and maximize their effectiveness during an emergency. Recommendations include locating it away from direct sunlight or any direct local area lighting that might impair the emergency message’s visibility.


Obviously, the code’s visible notification requirements continue to become more complex and will affect the fire alarm systems you install as a professional contractor. Unless you plan to design your own systems, the design engineer of record is responsible for choosing the correct notification appliances. The designer must ensure the proper location for all of the notification appliances in the system.


I suspect the visual messaging requirements will continue to change as the technology to provide emergency information develops. That gives you, as a contractor, yet another reason to stay abreast of the code and tech-
nology changes.

About The Author

MOORE, a licensed fire protection engineer, was a principal member and chair of NFPA 72, Chapter 24, NFPA 909 and NFPA 914. He is president of the Fire Protection Alliance in Jamestown, R.I. Reach him at [email protected]

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