Fire alarm one-way voice evacuation speakers in dwelling units

[Tainted]

I am designing a fire alarm system for a residential apartment building.

In NYC you are required to put speakers in dwelling units if the building is over 75ft tall.

What is a good rule of thumb for placement and spacing of speakers? Do you need one in every room?

What decibel levels do I need to achieve?

 

[gadfly56]

I am designing a fire alarm system for a residential apartment building.

In NYC you are required to put speakers in dwelling units if the building is over 75ft tall.

What is a good rule of thumb for placement and spacing of speakers? Do you need one in every room?

What decibel levels do I need to achieve?

Generally, we place them above or adjacent to the entry door. There is usually no additional requirements for system connected notification in the dwelling units.

 

[Tainted]

Generally, we place them above or adjacent to the entry door. There is usually no additional requirements for system connected notification in the dwelling units.

I wasn't talking about temporal 3 speakers. I was talking about voice evacuation speaker when FDNY picks up the mic by the building entrance and tells people to evacuate. (one way voice) Specifically this section of building code 907.5.2.2

 

[gadfly56]

I wasn't talking about temporal 3 speakers. I was talking about voice evacuation speaker when FDNY picks up the mic by the building entrance and tells people to evacuate. (one way voice) Specifically this section of building code 907.5.2.2

View attachment 2579005

I was actually talking about speakers. We have a Jersey City 26-floor residential high-rise with this arrangement. It is usually much easier to throw in a fire alarm voice system speaker than try to get the building intercom approved by the FD. The next intercom I see that's UL864 certified will be my first.

 

[Tainted]

I was actually talking about speakers. We have a Jersey City 26-floor residential high-rise with this arrangement. It is usually much easier to throw in a fire alarm voice system speaker than try to get the building intercom approved by the FD. The next intercom I see that's UL864 certified will be my first.

The difference is in New Jersey they don't require the speaker to be in dwelling units for one-way voice like NYC does

 

[gadfly56]

The difference is in New Jersey they don't require the speaker to be in dwelling units for one-way voice like NYC does

While technically true, Jersey City has pursued this as a "policy" looking for "voluntary" compliance. Again, if you need one-way voice to the dwelling units, do it with the fire alarm system. Unless you are talking about being able to do one apartment at a time. That's still doable with fire alarm voice, just more expensive. Better to do it a floor at a time, which is what you want anyway.

 

[Tainted]

While technically true, Jersey City has pursued this as a "policy" looking for "voluntary" compliance. Again, if you need one-way voice to the dwelling units, do it with the fire alarm system. Unless you are talking about being able to do one apartment at a time. That's still doable with fire alarm voice, just more expensive. Better to do it a floor at a time, which is what you want anyway.

I am doing it with fire alarm. Thing that sucks is that it's an existing building and putting speakers in existing dwelling units is going to be invasive and piss off a lot of people. I am not sure if it's required in kitchens, bathrooms or even bedrooms since it does not say where to put them in dwelling units.

 

[gadfly56]

I am doing it with fire alarm. Thing that sucks is that it's an existing building and putting speakers in existing dwelling units is going to be invasive and piss off a lot of people. I am not sure if it's required in kitchens, bathrooms or even bedrooms since it does not say where to put them in dwelling units.

The IBC/NYC requirement is hazy in my mind, but I believe it was to accommodate one and only one device, location decided by the AHJ. We don't do many, and no one so far has kicked about it being near the door to the apartment.

 

[Tainted]

The IBC/NYC requirement is hazy in my mind, but I believe it was to accommodate one and only one device, location decided by the AHJ. We don't do many, and no one so far has kicked about it being near the door to the apartment.

I might just do one for now and send it to FDNY for review after plans are done. If they want more, I will add more.

 

[Caddman99]

I am designing a fire alarm system for a residential apartment building.

In NYC you are required to put speakers in dwelling units if the building is over 75ft tall.

What is a good rule of thumb for placement and spacing of speakers? Do you need one in every room?

What decibel levels do I need to achieve?

A good rule of thumb is to place a speaker in each sleeping room and any location that could be used for sleeping (i.e. living room with a couch).
NFPA 72 requires 75 dB at the pillow.

 

[gadfly56]

A good rule of thumb is to place a speaker in each sleeping room and any location that could be used for sleeping (i.e. living room with a couch).
NFPA 72 requires 75 dB at the pillow.

Unless the AHJ is holding a loaded weapon to your head, no one can afford this sort of coverage for an apartment building, most especially a high rise. Well, if the units are going for $5,000,000 a pop, you could. Anything that would require that kind of coverage is a severe edge case.

 

[Caddman99]

Unless the AHJ is holding a loaded weapon to your head, no one can afford this sort of coverage for an apartment building, most especially a high rise. Well, if the units are going for $5,000,000 a pop, you could. Anything that would require that kind of coverage is a severe edge case.

Hi gadfly, The AHJ is given all the bullets they need in with section 18.4.6 of NFPA-72 (2025 edition reference).
Our local AHJ in CO is steadfast in enforcement of those audibility requirements. I also worked on a residential high rise project in Bellevue WA where the audibility requirement was enforced, but jurisdictions do vary.

You are correct, it is expensive to include those "extra" low frequency sounders in the initial design & installation, but the requirements of NFPA 72 are pretty clear and the cost of failing to meet minimum audibility levels at the fire final when the GC is screaming for his certificate of occupancy is exponentially higher.

Here is a very rough illustration based upon the info I scraped from a quick internet search: 1/2" drywall has a Sound Transmission Class (STC) of approximately 33 for a 125 - 4,000 Hz frequency range. This equates to roughly a 33 dBA drop as the evacuation tone passes from the living room sounder through the wall into the bedroom (assuming you are only installing a sounder in the living room on the common wall with the bedroom, and only passing through a single layer of drywall). System Sensor low frequency sounders produce a Sound Pressure Level (SPL) of 80 dBA at 10' for the high volume temporal setting. If you measure the SPL inside the bedroom with the door closed as NFPA 72 requires, you would only achieve a reading in the neighborhood of 47 dBA. That is well shy of NFPA requirements for sleeping areas of 75 dBA at the pillow. If you only install the low frequency sounder in the bedroom, then you fall short of the audibility requirement for the living room, which also is considered a sleeping area (NFPA 72, 18.4.6.4).

 

[Tainted]

A good rule of thumb is to place a speaker in each sleeping room and any location that could be used for sleeping (i.e. living room with a couch).
NFPA 72 requires 75 dB at the pillow.

75dB at the pillow refers to alarm notification. In NYC buildings 75ft+, inside dwelling units we are required to install speakers for paging purposes, not for alarm. Those are two different purposes.

 

[gadfly56]

Hi gadfly, The AHJ is given all the bullets they need in with section 18.4.6 of NFPA-72 (2025 edition reference).
Our local AHJ in CO is steadfast in enforcement of those audibility requirements. I also worked on a residential high rise project in Bellevue WA where the audibility requirement was enforced, but jurisdictions do vary.

You are correct, it is expensive to include those "extra" low frequency sounders in the initial design & installation, but the requirements of NFPA 72 are pretty clear and the cost of failing to meet minimum audibility levels at the fire final when the GC is screaming for his certificate of occupancy is exponentially higher.

Here is a very rough illustration based upon the info I scraped from a quick internet search: 1/2" drywall has a Sound Transmission Class (STC) of approximately 33 for a 125 - 4,000 Hz frequency range. This equates to roughly a 33 dBA drop as the evacuation tone passes from the living room sounder through the wall into the bedroom (assuming you are only installing a sounder in the living room on the common wall with the bedroom, and only passing through a single layer of drywall). System Sensor low frequency sounders produce a Sound Pressure Level (SPL) of 80 dBA at 10' for the high volume temporal setting. If you measure the SPL inside the bedroom with the door closed as NFPA 72 requires, you would only achieve a reading in the neighborhood of 47 dBA. That is well shy of NFPA requirements for sleeping areas of 75 dBA at the pillow. If you only install the low frequency sounder in the bedroom, then you fall short of the audibility requirement for the living room, which also is considered a sleeping area (NFPA 72, 18.4.6.4).

Did they suddenly decide to go all system, all the time for residential high rise? NFPA and the IBC require only local smoke alarms, not smoke detectors. The appendix note specifically excludes dwelling units in 18.4.6.1.

 

[Caddman99]

Did they suddenly decide to go all system, all the time for residential high rise? NFPA and the IBC require only local smoke alarms, not smoke detectors. The appendix note specifically excludes dwelling units in 18.4.6.1.

Hi Gadfly, Things changed when the requirement for low frequency tones came out in both IBC (907.5.2.1.3) and IFC (907.5.2.1.3). To the best of my knowledge, they don't make smoke alarms with low frequency sounders. Please correct me if you know of a COTS smoke alarm that complies with the 520 Hz requirement as I would genuinely seek that solution. The low frequency sounder requirement has triggered the push to change from smoke alarms to smoke detectors.

 

[gadfly56]

Hi Gadfly, Things changed when the requirement for low frequency tones came out in both IBC (907.5.2.1.3) and IFC (907.5.2.1.3). To the best of my knowledge, they don't make smoke alarms with low frequency sounders. Please correct me if you know of a COTS smoke alarm that complies with the 520 Hz requirement as I would genuinely seek that solution. The low frequency sounder requirement has triggered the push to change from smoke alarms to smoke detectors.

I looked into it a little more, and it looks like the IBC is targeting R-1 and R-2 occupancies for this requirement, which seems to go against the appendix note for 18.4.6.1. It wouldn't be the first time the code weenies decided to "fire, aim, ready". I have previously asked our Kidde rep when they might be fielding a 120/battery version of a 520 Hz sounder, but mums the word.