Fire Code Clarifications NFPA 72
June 24, 2014
As fire codes are revised, changes to the code are clarified and refined. This, argues Wayne Moore in a brief from the latest issue of NFPA Journal, is why facility managers and any one else that interfaces with a fire life safety system should be aware of the latest version of the code, even if their jurisdiction enforces an older version for the code.
For example, on area of confusion that is addressed in the latest version of NFPA 72, National Fire Alarm and Signaling Code, is intelligibility related to in-building fire emergency voice communication systems or mass notification systems. This is a relatively new aspect of the code, which can lead to some confusion around what the code actually requires. The code requires intelligibility, but it never intended to require that this intelligibility had to be quantitatively measured, says Moore. Doing so might be a great idea, but the technical committee only intended to require that people in the space understand the voice message. Exactly proving this through quantitative measurements is gravy. Moore says the problem is that misunderstanding the actual requirement could delay acceptance of a project by AHJs, hold back the occupancy permit, and add cost.
Another area of confusion around intelligibility is the "acoustically distinguishable space." Different spaces will behave differently from an acoustics standpoint because of physical characteristics of the space or how the space is used. So when designing systems for voice intelligibility, these space variances have to be taken into account. This concept came into the code with the 2010 edition of NFPA 72. However, in the 2013 edition the code was refined to clarify that not all acoustically distinguishable spaces necessarily have to support voice intelligibility (absent any other applicable codes, laws, or standards that might require intelligibility.) In Annex A, a list of spaces that might be exempt for the intelligibility requirements includes mechanical rooms, private bathrooms, kitchens and other similar spaces where it would be impractical to achieve intelligibility. In these spaces, alternatives to voice evacuation might be required, Moore says.
Read the original brief
here.
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