Temporal 3 Fire Alarm Systems

Michael Tobias
4 Minutes Read
  • Home
  • Blog
  • Temporal 3 Fire Alarm Systems

    No matter how careful you may be, a fire can break out unexpectedly in any building so an effective fire detection system as one of the building smart devices is paramount to ensure that the occupants of the building are entirely or partially evacuated to safety. Buildings are required by building codes to install fire alarm systems.

    Now, which alarm system should you install? Effective from the 1st of July 1996, the American National Standard (ANSI) has adopted the internationally standardized evacuation signal, now popularly known as the temporal 3 pattern, in short as T3. This signal complies with the standard ANSI S3.41 in America and ISO 8201, and it is referred to as the Audible Emergency Evacuation Signal by both standard organizations. Following its enactment, the NFPA (National Fire Protection Association) has enforced that all fire alarm systems to be installed after the 1st of July 1996 should utilize the temporal pattern. The conventional alarm systems with their constant audio signals can be modified to comply with the new building codes as highlighted by the NFPA 72 code.

    How does the Temporal 3 Fire Alarm System work?

    Unlike the traditional fire detection systems that use constant alarm signals, the Temporal 3 (T3) Fire Alarm System uses a pulsed audio signal that is repeated after 180 seconds. How this works is that it has a tonal sequence that becomes ON for half a second and OFF for the next half a second which continues for three cycles in succession. It remains silent for 1.5 seconds during those cycles.

    Some alarm systems fail in their purposes mainly due to poor audio or voice signals. NFPA 72 emphasizes the requirements of the temporary 3 pattern that it should be distinctive and should not be used for purposes other than fire notifications. Oftentimes, a fire notification can prompt various actions such as partial and complete evacuation. If a complete evacuation is required, then the T3 is highly required whereas for partial evacuation a voice-based signal is recommended to direct the building occupants to a safer place.

    Equally important, the building occupants must be trained on how to interpret the T3 fire alarm systems. Others may hear the sound but fail to respond to the actions if training has not been provided. To eliminate confusion that could arise in the failure of other alarm systems, the NFPA 72 code ensured that the temporal 3 fire alarm system remained relevant to society’s communication demands in fire detections.

    Installing the Temporal 3 Fire Alarm Systems

    For your fire protection needs, the T3 has to be installed according to the standards set and the right locations. For instance, the detection device should be 4 inches from the ceiling supply such as fans and air diffusers, and 10 inches from wall supplies such as air diffusers. Ideally, T3 alarm systems should be installed in locations that have combustible materials such as wood and plastics. Classrooms, work offices, corridors, halls, computer rooms, and many other storage areas should be prioritized when installing these alarm systems.


    If it seems challenging or burdensome to install these systems, MEP Engineers specializing in fire protection services can come to your rescue.

    Contact Us


    Do not forget the directory with all the emergency telephone numbers for relevant safety operators to be called by occupants should a fire break out. But, modern alarm systems come with smart control panels that serve as the brain behind the efficacy of the systems. For instance, the control panel can be programmed to automatically alert relevant authorities about the signaled fire. Meanwhile, the occupants will be able to vacate the building. Section 18.4.5.3 of NFPA 72 editions in 2010 and 2013 requires that the basic frequency of temporal 3 fire alarm systems should be 520 Hz frequency so it can awaken the occupants of the building.

    Benefits of the Temporal 3 Fire Alarm Systems

    Temporal 3 Fire Alarm Systems are automatic controls that bear huge benefits for homeowners in their fire detection strategies. As already indicated, some people fall victim to fire damage due to the failure to respond to alarm signals, and that failure is attributed to the alarm system’s inaudibility or distorted voice signals. Temporal 3 fire alarm systems prevent such inconveniences with their unique pulsed audio signals hence the NFPA enforces that buildings should have them. The NFPA 72 code also reinforces the requirements for mass notifications in weather emergencies, chemical emergencies, and many more threats.

    Temporal 3 Fire Alarm Systems versus Voice-Evac Systems

    You may ask if it is possible to use both the Voice-Evac and the Temporal 3 Systems. These systems have different prompts and thus could confuse if used simultaneously. For instance, the temporal 3 systems may prompt the occupant to vacate the building completely while the voice-evacuation systems prompt the occupants to relocate to a different region. Voice-Evac systems are pre-recorded in real time to offer commands. To install them in a building, especially a multi-story building, there must be speakers at every level to notify all the tenants. Typically, there is an audio amplifier credited to the voice commands. However, the temporal pattern may be installed as a backup should the voice evacuation fail to send the signals.

    Wrap up!

    Installing fire detection systems and automatic sprinklers in buildings has become a standard of all buildings to ensure the safety of the occupants. While there is a plethora of alarm systems from smoke detectors to heat detectors, the NFPA has set standards to be complied with when installing fire detection systems.

    The Temporal 3 fire alarm system was enacted as the standard on 1 July 1996. Therefore, all alarm systems installed thereafter should have this system. The old systems can also be modified to comply with the building codes and NFPA 72 requirements. The Temporal 3 fire alarm system operates in pulses with some silences in between to alert the occupants should there be a fire.

    Contact Us

    Tags : MEP engineers building automation system smart devices smart buildings automatic fire sprinklers
    Linkedin

    Join 15,000+ Fellow Architects and Contractors

    Get expert engineering tips straight to your inbox. Subscribe to the NY Engineers Blog below.

    Have a project in mind?
    Request a proposal