January 30, 2008 | | Comments 18
Print This Post
Email This Post

Reducing alarm decibel levels, NFPA 72 style

I was chatting with someone about the decibel level that fire alarms must be set at, and I thought, “Hey, a nice blog idea.”

The National Fire Alarm Code (NFPA 72) requires fire alarms to have an output (i.e., sound level) at least 15 decibels above the average ambient sound level or 5 decibels above the maximum sound level having a duration of at least 60 seconds, whichever is greater. You measure this decibel level 5 ft above the floor in the occupied area.

That said, NFPA 72 does say that audible signaling volume can be reduced, or in some cases, eliminated, when:

  • Approved by the AHJ (generally the local fire department)
  • Visible signaling is in place

If a fire alarm horn is so loud that the PA announcement can’t be heard, I would consider that an improvement opportunity and time to call the fire inspector.

Entry Information

Filed Under: Life Safety Code

Steve MacArthur About the Author: Steve MacArthur is a safety consultant with The Greeley Company in Danvers, Mass. He brings more than 30 years of healthcare management and consulting experience to his work with hospitals, physician offices, and ambulatory care facilities across the country. He is the author of HCPro's Hospital Safety Director's Handbook and is contributing editor for Briefings on Hospital Safety. Contact Steve at stevemacsafetyspace@gmail.com.

RSSComments: 18  |  Post a Comment  |  Trackback URL

  1. Mac, this issue is particularly important when considering neonates. Studies find that noise (and lighting) can have adverse developmental effects on small infants.

  2. If the budget will allow – upgrade and eliminate the Fire alarm horn – by discussing with the AHJ, the means to use private mode in lieu of public mode evacuation requirments – hospitals are allowed by the Code/AHJ to have planned evacuation using private mode notification. “chimes” versus those annyoing horns.

    but even better -I Highly recommend using
    voice evacuation notification…in such emergency situations, the AHJ will allow the Local fire warden to give commands (AKA the security personel or nurse call station at the front desk)for a coordinated and planned evacuation for ambulatory care facilities – so the the Fire alarm is the Public announcment – otherwise the PA is required to be fully disabled. The usual adopted code generally requires the Evacuation signal to overide all other notifications -In other words -one should not be able to hear the PA anyway.

    THe PA system would have to be a listed, FM/UL approved equipment for such emergency notification – a bogen, TOA or Common off the shelf equipment is not. IF your PA is listed, get rid of those horns.

  3. The decibel volume on these newer alarms with the flashing lights are excruciating. I ended up seeing a dr. after the school where I work did a fire drill and I was only about 5 feet away from the alarm. i was diagnosed with Acoustic Trauma (Explosive). My inner ear was very tender and hurt, but thankfully no damage. The pain subsided the next day. However, I am so fearful of another alarm. I almost fell over from the shock of it like a gun going off next to your head, but it doesn’t stop. I don’t see how this can be safe. I didn’t have students with me at the time, but if I had I don’t think I could have helped them if they needed help because I couldn’t take my hands off my ears. I don’t have children (my own) in school any more, but I would be furious if I did. This must be damaging to tender ears. There seems to be no reason for it so loud in a school where everyone hears, AND there are flashing lights AND there is a teacher in charge AND examples to follow of classmates leaving the room. these are set excessively loud for very deaf people, but because of the above reasons no need in a regular public school. The sound is so EXCRUCIATING.

  4. I agree with the previous comment. The school fire alarm where I teach is painful to my ears and many students. The foolish school head said I was a bad example by putting fingers in my ears (as many students do also), when actually the students should be encouraged to do the same if the sound level is painful. The decibel level is way too loud.
    I read that the db level should be 15 more than the ambient sound. Ambient sound of educational facility is 45, so the alarm should be at 60 decibels. My guess is my school level is near or above 100 decibels.

  5. They only sell fire alarm horns in the range of 75-90dBA, with most at 80dBA. Simplex sells a (legal) attenuator pad that reduces loudness 5-6dB. The loudness is both a signal and an incentive to get-out-of-there.

  6. Teachers and those with experience with Children with Special Needs will tell you of the disorder, and chaos that happens in their classrooms when the alarms go off. Many Children, especially those with Autism, feel actual pain, and trauma, and sometimes a lifetime of PTSD, as a result of the alarms. Our son, now 33, is one such person. He has been working hard to bring attention to this matter. As a result of his inquiries, the NFPA is presently doing a study on this issue. This is an important an timely subject, thank you.

  7. My previous entry related to our son, but I’d like to share an experience I had in a Hotel when the alarm went off. The sound was excruciating. So loud that I was unable to help people from a neighboring room that did not speak English. All I could do was point to the exit sign, finally taking one by the arm and leading him out. The sound was so loud, it made it difficult to think. It was really an impediment to safe evacuation.

  8. We just had a test of a new fire alarm system that was seriously so loud I’m sitting here with a throbbing headache. As Randy pointed out trying to explain to foreign students that missed the announcement that it was just a test was difficult and almost impossible.
    Randy, do you have a link to the NFPA study or more information as to the status of that study?

  9. If the fire alarm lists the device as 85 decibels at 10′, what is decibel increase at 5′. Would someone be able to provide me with either the equation or answer? Thanks!

  10. CM, the sound level will increase by 6db each time the distance is halved. It will increase by 6db each time the distance is doubled.

  11. Oops – It decreases as distance increases…

  12. Jun 28 2018 I conducted a Fire Drill in the Hospital Ambulatory Care Surgical center. We ran the Audio for about 4 minutes this would be about the time for the Fire Department to arrive in a real alarm. The audio alarms were very loud.
    The Evacuation plan is to relocate Surgical patients in a fire to the adjacent Smoke Compartment where Pre Admission Testing is done. However the audio is even louder there and no one can stay in that area and stand it.
    Why are “Evacuation” alarms, which drive you out of the building, required in a building where the plan is to relocate in the same building?
    Smoke Compartments are required as safe areas to move non ambulatory or unconscious patients into. This is now impossible. The Audio code has nullified any usefulness of the Life Safety Smoke Compartment code.

  13. I can not agree with this more. Our current hospital alarm system is set to audio levels that are physically painful. This is ridiculous. Fire chief won’t adjust. I get we need to know that the building is burning down, but the decibel level of these new alarm systems is absolutely ludicrous. The people who design this audio damaging crap should be forced to stay in the same room as one going off for 10 minutes. There’s no way 15 db above our ambient sound levels can possibly be that freakin loud.

  14. I am another such person similar to Randy’s son. Ive had to leave my condo because the alarms were so loud they could wake the dead. It shakes me to the core and can take months for the effects to away. It’s not safe for babies,special needs people/animals or anybody that’s gone through PTSD type physical or mental trauma.

  15. I feel the same. I live in a hotel in an accessible room for my brother in law, and our alarm goes off more than it should, usually to glitches or whatever. Last night it startled me so badly I fell off my bed and hurt my wrist a little. I was shaking for a couple hours afterwards. Today I am feeling highly anxious and I can’t settle down. Needless to say, sleeping was horrible.

  16. Sadly most of these companies are in bed with government facilities (There really isn’t anything truly private anymore and hasn’t been since post WW2) so they don’t listen to the actual customer’s needs.

    If we had true capitalism not ‘pseudo’ kind we live in today you’d be having your needs meet with fire alarms,security alarms,etc the best way possible instead of companies sit on their butts and throw away feedback until someone dies.

    This is a continuation of ‘Robber barons’ that have special protection.

    The noise levels IS a serious threat. What if your so deaf by false alarms you cannot hear properly real ones?

    Louder isn’t better. Sound should be lowered in volume and made to travel further in distance.

  17. I’d suggest the use of a voice-evacuation system – which depending on certain conditions may already be required.
    Voice evacuation systems are much quieter than traditional horn/strobes.
    See (and hear) a voice evacuation system in action: https://youtube.com/watch?v=jAeXjFPGxAI

    They are more expensive but if the building already has a PA/sound system, the alarm audio may be able to be wired into the PA system if the AHJ is willing to approve this. (usually on the condition of requirements like battery backup, volume overrides, priority, fault detection, etc…)

    Colonie Center near Albany, New York originally had horn/strobes, but during a renovation the horn/strobes were replaced with remote strobes and the alarm audio was wired into the sound system – it saves a lot of wiring costs. (although the stores and other areas not covered by the sound system have speaker/strobes)

  18. This seems to be a common issue. Nothing worse than a system that is so loud that no one wants to leave their space and pass near the device. Over the past 40 years that I have been in this business, NFPA 72 has continually increased the required dba from 60 to 75, and where it is measured. All of this so that we can obtain 75 dba at the pillow in the bedroom. The only way to accomplish that is to put a device into the bedroom. I do not blame manufactures for having units that loud as they need to meet the worst case situations.

    Here in the People’s Republic of San Francisco, they are requiring fire alarm retrofits to provide low frequency sounders, 75 dba at the pillow. That would typically require an 81 dba or louder unit depending on the location of the pillow versus the sounder.

    I have had clients install additional sounding devices to try to meet the old 70 dba at the bedroom using devices in the public hallways of the apartment houses. Once they were installed the tenants no longer complained that they could barely hear the devices. Now they complain that it hurts to leave their apartments so they will not unless directed by the fire department.

    NFPA needs to stop massaging the code and come up with a reasonable solution. We cannot have a perfect design or world.

RSSPost a Comment  |  Trackback URL