Hi everyone, Mike B here! As a Regional Sales Manager I get called out to perform building walk-throughs on a fairly regular basis. Unfortunately, the driving factor for these visits is a problem. I’ve been to multiple Fire Voice installations with the same theme: “not enough”. I want to share just a few observations of what “not enough” could mean.
Not Enough Light
There is no inexpensive and reliable way to measure strobe light in the field. You might take a common sense approach to this problem. If you can’t see the light then there’s not enough. In factories, warehouses, and even offices, there can be dead spaces. Your local Fire Marshalls are exceptional at finding them! When the fire and voice systems are active, there should be no area within your space where you cannot see a strobe or have your attention captured by a strobe. In larger spaces with high ceilings, light gets absorbed quickly and even high candela strobes can seem dim. Some of the most common inspection failures related to strobes is the dead space between racks or pieces of machinery. 100% coverage is key! If it’s a space where people work or through which people travel, a strobe should be visible.
Not Enough Sound
This is a biggie! The “voice” in “voice evacuation” needs to be heard above the ambient noise in any occupancy. Dead spots can occur when not enough sound/audible devices are deployed. Note: I have used a simple iPhone app to measure sound with limited success. Think of this as an indicator rather than a measurement.
Keep in Mind
More is better. We know that when sound reaches us from several different places that it becomes clearer and more intelligible, (intelligibility is the understanding of the message). High ceilings, cavernous lobbies, marble floors and/or walls can be the enemy, (background or ambient noise levels can play a big part as well). Just like big spaces absorb light, these big spaces can absorb sound and can even add an echo effect, significantly decreasing intelligibility.
Walls and ceilings. In tight spaces like hallways, a ceiling mounted speaker will tend to project sound where if you deployed wall speakers in the same space the sound would likely bounce off the opposing wall or worse, get absorbed. In big open spaces, especially those with high ceilings, wall speakers will work better than ceiling mounted as they will be closer to the ear. Remembering that more is better in terms of intelligibility of the message, more is better in terms of volume as well and don’t forget the dead spots between racks or behind partitions.
Speaker placement is important. Speakers placed facing each other, for example on opposing walls, will tend to cancel each other out. Just like you would stagger strobes to gain greater coverage within a space, stagger the sound to avoid cancelling. It’s a lot easier to lower the tap setting on a speaker that might be considered extra than it is to cut a hole in marble or otherwise finished walls, and then there’s the wiring…
Looking for more?
Fire-Lite Alarms and AFMG teamed up on a webinar to discuss in-building and outdoor ECS design with a review of code and guidelines. The webinar included an in-depth look at how EASE Evac software can help you with your design. For more information on the EASE Evac Software please visit: http://evac.afmg.eu/ If you’d like to watch the on-demand recording of the webinar, please visit our website.
About the Author
Mike Breault is the Northeast Regional Sales Manager for Fire-Lite Alarms and has previously worked as a Fire-Lite Alarms Programming and Installation Trainer and SME. He joined Honeywell Fire Systems in 2007 and has worked for Honeywell for over 11 years.