Fire Side Chat: Ensuring They Get the Message

Last month, we covered the basics of the life-safety discipline referred to as mass notification systems (MNS). This relatively new technology area aims to disseminate critical information among a large number of people in quick fashion.

Zone-Based and Real-Time MNS
By integrating MNS and fire detection, it’s possible to do a lot of really neat things. Zone-based notification is one of the nifty things that make it possible to target specific areas of a facility or complex, issuing specific announcements geared toward specific threats in precise areas of a facility or multiple-building campus.

Automated selection of canned MNS messages is made possible in part in accordance with data received from individual addressable heat sensors and smoke detectors. The bottom line is the provision of timely information with the intent of saving lives and reducing the number of injuries that result from a catastrophic event.

These systems also provide the means whereby management and firefighters can make real-time announcements using a microphone. These mikes are usually part of the MNS control system. This gives fire authorities the ability to send crucial instructions to specific occupants of a building based on changing environmental information as conditions change. This includes floors, rooms, segments and entire wings of the building.

With this in mind, in our previous example if a tornado is bearing down on the complex, authorities might elect to instruct occupants on the remaining floors to evacuate to another location within the building, such as a tornado shelter in the basement. This would be done floor by floor based on incoming data retrieved from sensors throughout the high-rise structure.

There’s no doubt ECS technology is here to stay.


Messaging Methods

A mass notification system (MNS), like its fire EVAC counterpart, is designed to provide canned or preprogrammed messages that allow the system to address emergencies in targeted areas of the building or campus. Using multiple amplifiers with programmable zone outputs, it’s possible to send specific messages to specific areas or zones as needed.

These systems are usually capable of providing a number of messages. Unified Facilities Criteria (UFC) specifically requires eight canned messages but there can be more. This enables the system to react to almost any number of emergencies, such as weather alerts, HAZMAT incidents or a security breach. This is especially important for Department of Defense (DoD) installations and institutional facilities, such as public schools, colleges, universities and government buildings.

For example, when a fire caused by severe lightning is detected on floor 12 of a high rise and all the stairways at floors 12 and above are filling with smoke, the system can automatically instruct occupants on floors one through 11 to proceed downward to the nearest exit/stairway. At the same time those on floor 12 can be ordered to proceed to a specific safe area on the same floor. Floors 13 and above can be handled differently by having those folks proceed to another floor above.

Emergency tones and verbal messages must be administered in a prescribed manner. For example, when e
vacuating a building, “Evacuation messages shall be preceded and followed by a minimum of two cycles of the emergency evacuation signal specified in 18.4.2” (Section 24.4.1.2.1, NFPA 72, 2010 Edition).

A 520Hz square wave tone also is required as a prealert tone when sleeping quarters are present. The purpose of this under Section 24.4.1.4.1 is to assist hearing impaired individuals.  When conducting a partial evacuation and/or relocation within a facility, a continuous 3- to 10-second warning tone followed by verbal instructions is required. 
According to Section 24.4.1.4 of the new NFPA 72, these emergency tones can be part of the prerecorded message or they can be generated by a separate tone generator inherent within the emergency communications system.

 

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About the Author

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Shane Clary, Ph.D., is Security Sales & Integration’s “Fire Side Chat” columnist. He has more than 37 years of security and fire alarm industry experience. He serves on a number of NFPA technical committees, and is vice president of Codes and Standards Compliance for Pancheco, Calif.-based Bay Alarm Co.

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