Health Care Fire Alarm Audible Alarm Question

[tmillard]

In 2003 we designed a new addition to a hospital on the east coast. During the fire alarm test, the local inspector walked around with a dB meter checking the sound levels throughout. He is flagging us on a number of areas since they are not 15db above and ambient level.

The project was started in 03 so we are following IBC 2000 (907.9.2) and NFPA 72 7.4.2.1 (2002).

We understand that hospitals follow 'defend in place' which means they won't evacuate the building in the event of an alarm, and we have had several previous complaints about the fire alarm being too loud (staff complaints...)

Has anyone run into this issue before?

Thanks,

Tom

 

[DUCKMAN]

Public or Private

Public or Private

Was the system designed (and approved) as public mode or private mode?

 

[tmillard]

Public or Private Mode

Public or Private Mode

I believe the system was designed as public mode.

 

[Fire Alarm]

How have you determined just what the ambient level is? Realistically it is the average sound pressure level over 24 hours. This problem might be resolved through the redefinition of what "Ambient" is...

 

[ron]

I have run into this and have had the installer increase the wattage taps on the speakers (if they are speakers) to account for higher volume. Be sure that you don't run into amplifier capacity or voltage drop issues.
Speakers must also be intelligible (be understood), so be sure there is enough speakers so you don't get a "stadium" or "NYC Subway" effect.

If they are horns, then you are out of luck and need to add. Usually Hospitals are speakers, so I hope you can just raise the taps.

 

[tmillard]

Fire Alarm

Fire Alarm

Thanks for the responses...

The hospital took readings prior to construction and stated the average sound level was 40dB. The fire alarm manufacturer/installer has bumped up all the taps on the speakers and there are still some instances where we fall below 55dB.

Based on these issues, I believe the right thing to do on all future projects in use all speaker/strobes in lieu of a combination of strobes and speaker/strobes.

Tom

 

[Life Safety]

I'm new to the site, so please excuse any fau paux. In most hospitals I've seen, they use chimes, chime/strobes, or strobes in area's like restrooms. However, the last hospital I worked at had horns, horn strobes and a voice evac for the dining area ( over 300 occupancy). The hospital personel hate it every time it goes off.

 

[Weaver Road]

Debated This Just Yesterday

Debated This Just Yesterday

Greetings to all. First, I am new today, but this is very on topic for me. My office just had a meeting with multiple AHJs on this very topic. If it's still of interest, I have a few comments to add.

Keeping in mind the differences in codes and interpretations by AHJs:

The Fire Code does not actually recognize the principles of "protect in place" or "defend in place" directly. More directly it speeks to the impracticality of moving certain persons. The principle of the fire code is still evacuation, even if delayed.

In private mode, the designated staff must still be notified by some means immediate and in a format approved by the AHJ (chimes, page over PA, etc.).

In public mode everyone knows about it.

AHJ can approve in some instances the use of visual only even in public mode.

Areas seperated from the healthcare areas by certain provisions like fire seperation assemblies, etc, likely will still be required to use a normal public mode evacuation signal or meesage.

The NFPA 72 provisions for pre-signal or alarm verification may not be allowed by the AHJ in healthcare occupancies.

The ambient reading done before the reconstruction of the area discussed above is not fair game in my mind as the new surfaces alone may have changed the sound reflection qualities never mind that all of the systems in place may have greatly altered the ambient reading. Just try an ambient reading with a desk fan off then on and you will see the problem there.

The 24 hour average for ambient is not something I have heard before, but I am interested to hear how other inspectors do this. I find there is a lot of different info on sound metering as well as light metering for the emergency lighting, but that's another problem all together!

Hope this brings more info and thought to the debate, I would be happy to hear other's responses.

WR

 

[MichaelGP3]

Something you might want to consider.....

Something you might want to consider.....

.....

Based on these issues, I believe the right thing to do on all future projects in use all speaker/strobes in lieu of a combination of strobes and speaker/strobes.

Tom

would be to specify the same type of backbox (example: 1 deep 4" square box and 1 standard depth extension) for the strobes as are provided for the speaker/strobes. This way, should a strobe need to be replaced with a speaker/strobe to address sound pressure level deficiencies, at most some additional labor is required for wire pulling, but no 'retrofitting' backboxes (that already have wire pulled in/thru them!) or wall patching will be required. If 4" square strobes are available from the vendor, the electrician can set all the extension boxes flush with the sheetrock, making the install a little simpler. Having said all this, I'm not sure whether my suggestion is more cost effective than your idea.....