As technology pervades our everyday lives, people expect to receive instructions during emergency situations. Emergency communications systems (ECS) continue to evolve, incorporating multiple modes of disseminating information. ECS inform people about what to do and where to go, providing a measure of order to a potentially chaotic and stressful situation. The guidelines defining how this is accomplished come from the National Fire Protection Association (NFPA) Part 72 in the United States and the EN-54 Fire Detection and Fire Alarms Systems within the European Union. NFPA is a code providing a foundation for local municipalities to set their own life safety requirements that drive the ECS solution. EN-54 is a law stipulating that products must meet specific requirements of certification. We will focus on the NFPA in this post, but the concepts parallel EN-54 as well.

The NFPA Part 72 is updated every three years — with the 2016 version being the most current — providing more comprehensive terms, definitions, and requirements of emergency communications systems. NFPA 72 defines three critical terms every ECS must address: audibility, intelligible, and intelligibility.

Audibility requires the alarm tone to be 15 dB above any ambient noise — but only the alarm tone, not voice messaging.

Intelligible is the ability to understand any directions communicated. Consider this example: if you were a visitor to an office building, and given verbal instruction to exit out of stairwell three because a fire suddenly broke out, you probably wouldn’t know where to go. Giving that direction, even at an audible volume, does not make it more intelligible. As required by NFPA code, messaging must make sense to everyone in the space, and signage must be used to clearly indicate the escape route or location of refuge.

Intelligibility is the acoustic measurement of a space to provide the optimal environment for hearing the system’s voice messages. The code requires an average Sound Transmission Index of .5 for the entire space. This means in large spaces with hard reflective surfaces, acoustic technologies, such as steerable arrays, must be employed to increase the speech intelligibility of the ECS.

How Can Vocia Help?
Vocia is designed to intelligently and automatically address each of the terms within the revised 2016 NFPA 72 code. Thanks to Biamp’s DSP technology, Vocia applies intelligence to its emergency alert systems. It precedes its alert messages with a tone that is picked up by the ambient noise-sensing device (Vocia ANC-1) that measures how loud the space is at that given moment. This ensures that the ensuing alarm plays 15 dB louder than the ambient noise in the area. The system automatically drops to the appropriate volume to broadcast the instructions — even in several languages — to meet the intelligibility requirement of the space. Finally, a closing tone sounds again at 15 dB above the ambient volume.

In the ECS marketplace, Vocia stands out for its distributed, decentralized architecture. Other emergency communication systems use a centralized processor. If that processor fails, the entire system fails. Vocia utilizes distributed networking with system intelligence residing in each local device. Should a device fail, only that device is impacted, and the remainder of the system is still in place. Vocia’s internal monitoring feature immediately reports any failure so corrective measures can be taken. There are also redundancies built into every device, so that in the event of failure, another device can back it up.

Intelligence and Flexibility
The fire alarm is no longer the end-all-be-all for emergency notification. Previously, if the fire alarm was going off, everything else took a back seat. Recent situations have made the authority having jurisdiction (AHJ) realize that numerous systems must be employed, and employed in different ways, depending on the nature of the emergency. Alarms are never deactivated or ignored; instead verbal direction is now allowed (in predefined ways) to take precedence over the alarm that may be occurring at the same time. These are all intelligent and automated functions that Biamp has researched and built into Vocia to address and meet the latest standards in emergency communications, whether deemed critical now or in the future.

Want to learn more about Vocia’s advanced capabilities? Check out the full-length article in the June 2016 issue of Component.

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