In the last two columns, I’ve discussed the new sales opportunity for your company to begin offering directional sounders to supplement the fire alarm notification appliances you are already installing per the building/fire codes. While not (yet) required by these codes, directional sounders can provide a more complete evacuation of occupants and at the same time occupants have shown a 75 percent improvement in evacuation times when smoke is present and up to 35 percent faster without smoke. This month we conclude our series with the nuts and bolts of proper placement throughout the egress path and the various optional settings to use at each location.
Fire alarm signaling
It is the job of the horn/strobes to notify the building occupants of the need to evacuate or re-locate if a voice evacuation system is used. The directional sounders then help the occupants get to safety. Audible evacuation signals, including horns, bells and voice alarm systems, must be clearly heard throughout the building, at least 15 decibels above the average ambient sound. Directional sounders are compatible with all of these, even though they provide a sound level equal to or greater than the fire alarm notification appliances in that area. Since horns and bells are tonal, their sound is not masked by the pulsing, broad spectrum of white noise from directional sounders.
According to research, in addition to the broadband noise, the sounder is capable of playing an alert message in the form of a recorded voice message or other audible signals. These messages will instruct the occupants of what action to take as they approach the directional sounder and will allow them to react quickly and confidently when the sounder is activated. Fifteen different language combinations are available to instruct occupants that they are nearing an exit, a stairway or an area of refuge.
There are two specific application levels. The basic installation is called Type 1 and the enhanced installation is called Type 2. The manufacturer’s published guidelines for these sounders must be strictly followed and the directional sounder concept must be well understood by the designer since it is possible to lead people astray, possibly resulting in death.
Directional sounders may be added to a network access control (NAC) with other notification appliances or wired on their own circuit, or their own NAC power supply. They are not compatible with pulsed circuits (temporal three and coded signals) but with circuits using sync modules. Traditional fire alarm notification appliances must be provided and spaced so that they are clearly heard in all holding areas.
Operation of directional sounders
The white noise component of directional sounders includes settings for four pulsing speeds; fast, medium, medium slow and slow. Directional sounders feature five field-selectable power settings (sound levels) which allow an adjustable range from 73 to 85 dB. The 15 available voice options and other sounds may be used to provide additional egress information to the evacuees. This may be best applicable in areas where multiple nationalities are present (tourist areas, theme parks, cruise ships, etc.) or when the proper direction to travel in a stairwell isn’t down.