How to Maximize Existing Fire Alarm Systems by Adding Intelligible Voice Communications

Get answers to questions on how to guide conversations about retrofitting existing fire alarm panels with mass notification capabilities.

Do the performance criteria for voice fire alarm systems differ from other emergency communication systems?
No. All emergency communication systems should alert building occupants and key personnel to what is happening and where it is occurring. The notification is only effective if it gives direction on how to act and what to do. Vital safety information needs to be clear and understandable.

Voice fire alarm systems need to meet the same requirements.

What kind of regular maintenance or testing must be done for a voice fire alarm system?
Voice fire alarm systems are tested annually and are typically operational on their own network. To gauge the intelligibility of the communication, testing is best done while the building is occupied. The same requirement applies for a dedicated in-building fire emergency communication system.

Why should it matter if voice fire alarm systems are UL listed?
All systems should be UL listed for their purpose. If a voice fire alarm system is used, then it will need to meet UL864. And as part of this, the speakers must be listed with the control unit. 

How is intelligibility tested?
NFPA 72 Annex D provides guidance on this complex issue. NEMA SB-50 Emergency Communications Audio Intelligibility Applications Guide is another great resource for intelligibility.

Which specific codes apply to intelligibility and emergency communication systems?
The 2010 edition of NFPA 72 was revised to cover a broader array of life-safety systems, including emergency communication systems. Three chapters in particular address intelligibility and emergency communication systems: Chapters 14, 18, and 24. After the type of system, based on occupancy, is determined, NFPA 72 indicates how to install the required system.

The 2015 edition of NFPA 101 was revised to require voice in educational occupancies per The occupant notification required by shall utilize an emergency voice/alarm communication system in accordance with 9.6.3 where the building has an occupant load of more than 100.

This matches the 2015 edition of the International Building Code [IBC], which now states in Section 907.2.3, Exception 2 that emergency voice/alarm communication systems meeting the requirements of Section 907.5.2.2 and installed in accordance with Section 907.6 shall not be required in Group E occupancies with occupant loads of 100 or less (30 or less in 2012), provided that activation of the manual fire alarm system initiates an approved occupant notification signal in accordance with Section 907.5.

In terms of voice fire alarm systems, what is included in Chapter 14 of NFPA 72?
Chapter 14 of NFPA 72 covers inspection, testing and maintenance of various fire and life safety systems. This chapter includes emergency communication systems as well as revised requirements for the testing of intelligible voice communications.

How about in Chapter 18 of NFPA 72?
NFPA 72, 2010 edition, introduces the Acoustically Distinguishable Sp
ace [ADS] as the starting point in “design” to identify those areas in a building where intelligibility is required. It is accepted that intelligibility may not be accomplished in all spaces/areas in a building. However, at a minimum, “audibility” must always be obtained in all areas.

The specific rules for 18.4 Audible Characteristics follow:

• Voice messages shall not be required to meet the audibility requirements of 18.4.3 (Public Mode Audible Requirements), 18.4.4 (Private Mode Audible Requirements), 18.4.5 (Sleeping Area Requirements) or 18.4.6 (Narrow Band Tone Signaling for Exceeding Masked Thresholds) except as required, but shall meet the intelligibility requirements of 18.4.10 where voice intelligibility is required.

• 18.4.10 Voice Intelligibility. Within the acoustically distinguishable spaces where voice intelligibility is required, voice communications systems shall reproduce prerecorded, synthesized, or live (e.g., microphone, telephone handset, and radio) messages with voice intelligibility.

What does Chapter 24 of NFPA 72-2010 edition say?
Chapter 24: “Emergency Communications Systems” – New requirements should be incorporated into system designs: audibility, intelligibility, survivability, supervised circuits, and ADS.

• 24.2.1. The systems covered under Chapter 24 are for the protection of life by indicating the existence of an emergency situation and communicating information necessary to facilitate an appropriate response and action.

• 24.2.2. This chapter establishes minimum required levels of performance, reliability, and quality of installation for emergency communications systems but does not establish the only methods by which these requirements are to be achieved.

Key changes regarding mass notification use with fire alarm systems include the need to have a Risk Analysis up front as part of the design process, as well as a new Emergency Response Plan that will explain what to do in an emergency. The response plan must align with the design of the system.

• Speakers used as alarm notification appliances on fire alarm systems shall also be permitted to be used for mass notification.

• Priority
o When the fire alarm system has been activated, and mass notification has been given priority, an audible and visible indication shall be provided at the building fire alarm control unit.
o The fire alarm system shall not automatically override emergency mass notification messages.

• Risk Analysis for Mass Notification Systems
o Each application of a mass notification system shall be specific to the nature and anticipated risks of each facility for which it is designed.

Will NFPA 72, 2010 edition, be revised in the near future? If so, what are the main proposed changes that could affect emergency communication systems?
Yes, the 2013 edition is already published and referenced in the 2015 edition of the IBC and IFC. The 2016 edition is being developed and will be voted on at the NFPA Technical Meeting in June 2015 in Chicago. Changes in both new editions aid in clarifying the installation and design requirements for emergency communication systems. A detailed review should be performed for jurisdictions that are adopting the newer editions.

Do certain types of buildings require voice fire alarm systems?
Yes. All high rise buildings require voice systems and recently, per NFPA 101 and IBC, elementary and secondary schools [grades K-12] that have at least 100 students are required to have voice fire alarm systems.

Intelligible voice communications will play an increasingly critical role in the design and installation of fire/life-safety systems of the future. The next evolution of large buildings will not be designed with evacuation of tenants/employees in mind; rather, they will be designed for “defend in place” and “occupant relocation” scenarios. For that, a reliable emergency communication system is needed to give clear, concise directions that can be easily understood. 

Additionally, being aware of code changes on the horizon can help provide end-users with longer lifecycle solutions that will ensure the safety of building occupants for years to come.

Maria Marks, CFPS, SET, is a national business development manager with Siemens’ Building Technologies Division. She can be reached at (202) 236-3406 or

Dan Finnegan, CFPS, is a manager of industry affairs at Siemens’ Building Technologies Division. He can be contacted at (630) 240-4328 or

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