Worried About New Code Requirements? We Have You Covered

NFPA 72 (National Fire Alarm and Signaling Code) now requires that audible appliances installed in certain sleeping areas produce a low frequency (520 Hz) alarm signal in a square wave form.

Low frequency (520 Hz) alarms have been proven to be more effective at waking individuals in the event of a fire, including those with mild to severe hearing loss, those under the influence of alcohol and young children. For this reason, low frequency devices are now required in many commercial sleeping spaces across the country according to the latest NFPA 72 standards. To help you meet these new code requirements, Silent Knight offers the most versatile and easy-to-use line of low frequency sounders, sounder strobes and sounder bases in the industry.

Available with white or red plastic housings, field-selectable candela settings and a rotary switch for selecting sounder tones, Silent Knight’s sounder and sounder strobe low frequency devices meet virtually any application requirement. These devices also feature plug-in designs with minimal intrusion to the back box making installations fast and foolproof while virtually eliminating costly and time-consuming ground faults.

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Also available to help you meet these new code requirements are Silent Knight’s low frequency sounder bases. These intelligent bases are compatible with addressable Silent Knight smoke detector heads and adopt the same address as the detector but as a unique device on the loop. This allows the fire alarm control panel to command an individual sounder, or group of sounders, to activate and offers the flexibility to tailor alarms from the fire alarm control panel for specific events including the selection of volume, tone and group.

Silent Knight’s low frequency sounders, sounder strobes and sounder bases meet the new NFPA 72 code requirements and integrate seamlessly with your existing Silent Knight fire alarm system. These low frequency devices can also easily be retrofit into existing installations helping you meet the new code requirements quickly and economically.


  • Meets NFPA 72 Low Frequency Code requirements
  • Universal Mounting Plate
  • Available Devices: Sounders, Sounder Strobes, and Sounder Bases
  • 3 Selectable Tones: Temporal 3, Continuous, and Coded; Field-Selectable Candela Settings

For more information, visit: silentknight.com/lowfrequency.

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