The requirements for intelligibility are found within Chapter 18, Notification Appliances and Chapter 24, Emergency Communications Systems. In addition, a new Annex D, Speech Intelligibility was added.
Key Areas of Audibility
Here’s a rundown of client locations that may require voice intelligibility within their protected premises’ fire alarm and emergency communications systems:
- Theaters
- Places of worship
- Schools
- High-rise occupancies
- Casinos
- Restaurants
- Transportation hubs or terminals
- Museums
- Malls and shopping centers
- Amusement park rides
Section 18.4.10 added the requirement that when designing a system in which voice intelligibility is required, Acoustically Distinguishable Spaces (ADS) must be included as a part of the design. The addition of the ADS recognizes that not all areas or spaces within a premises may require voice intelligibility. This section allows the designer of the system to designate where intelligibility is and is not to be provided.Section 24.4.1.2 Voice Evacuation Messages offers requirements for voice intelligibility within voice systems. This section also provides a list of areas that do not require intelligibility, unless required by the AHJ. This list includes private bathrooms, mechanical spaces, elevator cars, individual offices, kitchens, storage rooms and closets.In the 2013 edition of 72, the requirements that are found in the 2010 edition stayed the same with one exception. Paragraphs 18.4.10.4 and 18.4.10.5 were added: 18.4.10.4 Intelligibility shall not be required to be determined through quantitative measurements. 18.4.10.5 Quantitative measurements as described in D.2.4 shall be permitted but are not required.Prior to this, the system installer would have to use special test equipment to demonstrate that the r
equired intelligibility had been achieved. By the 2013 edition, the Technical Committee for Notification Appliance took a common sense approach, and allowed that if the message could be understood during testing and acceptance then special quantitative methods would not be required.Next month I will attempt to put this all together so that you will be able to design and install a basic system in which voice intelligibility is required.
