“If a tree falls in the forest and there is no one there to hear, does it make a noise?”

In a roundabout way, that same age-old question could also apply to fire-code driven emergency voice evacuation systems: “If people can’t understand what is being said, will they listen?”

The question leads to the case for measuring “Speech Intelligibility” in particular Acoustically Distinguishable Spaces (ADS) for emergency communication systems connected to fire detection/security systems.

“As the state regulations change across the country per the National Fire Protection Association (NFPA) recommendations, a great deal of confusion is starting to arise,” says Matthew Miller of Gold Line Connectors in Redding, Conn. The company is developing a series of 5- to 10-minute training videos for integrators to hone their skills in measuring Speech Intelligibility.

“While some states adhere completely to the NFPA recommendations word for word, others only adopt certain portions of their recommendations. To further complicate matters, the NFPA is always in the process of looking for ways to improve upon their recommendations. These recommendations do not only cover the civilian world, they also cover the Department of Defense as well as all government agencies. Speech Intelligibility requirements are not only a part of the United States, they are being adopted around the world in an ever growing list of countries.”

“One of the most confusing parts of the NFPA recommendations came about with the advent of ADS, or certain types of locations within a building. Some of these locations will require a passing score for intelligibility, while other areas will be exempt from testing. The reason for this came about because it was clear that certain areas simply could not achieve a passing score without causing major problems, while other areas would not typically have people congregating for long periods of time within the spaces,” notes Miller.

Gold Line’s video series, which will be posted on YouTube for integrators to watch beginning in September, will show how to test ADS areas in various types of rooms within a commercial facility, including a gymnasium, office and kitchen for public events. In general, the videos will cover how to locate the proper regulations and test procedures required to perform a Speech Intelligibility Test using a Gold Line DSP2B and a DSP30B speech Intelligibility Meter as well as a Gold Line TalkBox.

The proposed topics for the videos include: Determining ADS’s and code requirements; test procedures, a basic overview for types of Speech Intelligibility, methods for injecting STI-pa tones into an ECS Panel; setting up a TalkBox; and measurement techniques for empty and occupied rooms with or without a computer.