July 29, 2015 – The National Electrical Manufacturers Association (NEMA) has published NEMA SBP 4-2015 Low Frequency Audible Signals.

This new white paper addresses the development of the low-frequency audible signal used in fire alarms, carbon monoxide (CO) alarms, and fire or CO alarm systems. The Fire, Life Safety, Security, and Emergency Communication Section developed the document. It speaks to why a low-frequency signal is needed, the difference between the low-frequency signal and the standard audible fire alarm signal, and when and where the low frequency signal is required.

NEMA SBP 4-2015 may be downloaded free of charge on the NEMA website.