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Introduction to Fire Alarm Sirens

A fire alarm siren is a critical component of any fire safety system, designed to provide a loud, audible warning in the event of a fire. These sirens are installed in buildings and other structures to alert occupants to evacuate or take emergency actions. Eterna bilding Automation Pvt Ltd offers state-of-the-art fire alarm siren systems that ensure comprehensive and effective fire safety.

How Fire Alarm Sirens Work

 

Activation and Control

Fire alarm sirens are typically activated by a fire alarm control panel. This control panel receives signals from fire detectors or other components of the fire alarm system. Some fire alarm sirens are integrated with a public address system to provide verbal instructions and additional information to the building occupants during an emergency.

 

Audible Alarm Signals

Audible fire alarm signals must provide a clear and unmistakable warning to all intended recipients. For most buildings, this implies that all occupants should be able to hear the alarm. However, in specific settings such as hospitals or rest homes, it may be more appropriate to alert staff who can then assist residents.

Technical Specifications :

Sound Pressure Level (SPL)

The general requirement for the volume of audible alarm signals is a Sound Pressure Level (SPL) of at least 65dB(A), but not more than 120dB(A) throughout all accessible areas of the building. Exceptions include:

  • In stairways, the SPL may be reduced to 60dB(A).
  • In enclosures less than 60m², the SPL may be reduced to 60dB(A).
  • There is no minimum SPL requirement for enclosures less than 1m².
  • At specific points of limited extent, the SPL may be reduced to 60dB(A).
  • Where continuous background noise exceeds 60dB(A), the fire alarm signal should be 5dB above the ambient noise level, but not greater than 120dB(A).

Alarm Placement

For alarms intended to wake people, an SPL of 75dB(A) is required at the bed head, typically necessitating the placement of a sounder within the room. If placing a sounder within a room is not feasible, it’s important to consider sound loss: approximately 20dB(A) through a standard door and 30dB(A) through a fire door.

 

Hearing Safety

Warning: Volumes greater than 120dB(A) can cause hearing damage. In open spaces, as the distance from a sounder doubles, the sound level is reduced by 6dB(A). It is preferable to use multiple quieter sounders to achieve the required sound level rather than a smaller number of loud devices to prevent points of excessive volume, which may cause disorientation or hearing damage. Two sounders providing equal sound levels will combine to add 3dB(A) to the SPL.

Visual Alarm Integration :

In compliance with the Disability Discrimination Act (DDA) and for use in areas with high background noise where hearing protection may be worn, visual alarms are essential. Visual alarms should be:

  • Clearly distinguishable from other warning lights, preferably red.
  • Flashing at a rate of 30 to 130 flashes per minute.
  • Mounted above 2.1m, but not closer than 150mm from the ceiling.
  • Positioned to be clearly visible from all locations within the protected area.

Key Features

  • High Decibel Output: Ensures audible alarms are heard throughout the building.
  • Public Address System Integration: Provides verbal instructions during an emergency.
  • Compliance with Safety Standards: Meets or exceeds SPL requirements for effective fire warning.
  • Visual Alarm Compatibility: Ensures comprehensive alerts for hearing-impaired individuals.

Eterna Automation Pvt Ltd offers advanced fire alarm siren systems that are crucial for effective fire safety. These systems provide clear, audible warnings and can be integrated with public address systems for additional safety measures. With the added option of visual alarms, Eterna Automation ensures comprehensive protection for all occupants, enhancing safety in residential, commercial, and industrial settings.