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Showing posts with label 520 Hz Sounders. Show all posts

Saturday, February 18, 2023

520 Hz Low Frequency for 120VAC Smoke Alarms IFC 2021

How is the new 2021 International Fire Code going to impact your fire alarm design and costs for Group R-1 and R-2 occupancies?

If you install fire alarm system in the residential vertical market, you need to keep reading.

When designing and pricing a new fire alarm system for group R-1 (hotels and motels) and R-2 (apartments, townhomes, and condos) you need to factor in 520Hz low frequency sounders for sleeping rooms. this is found in the 2021 International Fire Code (IFC) and 2022 NFPA 72 standard as follows:

2021 IFC Section 907.4.2.1.3
Audible signal frequency in Group R-1 and R-2 occupancies shall be in accordance with Sections 907.5.2.1.3.1 and 907.5.2.1.3.2

2021 IFC Section 907.5.2.1.3.1
In sleeping rooms of Group R-1 and R-2 occupancies, the audible alarm activated by the fire alarm system shall be 520-Hz low frequency signal complying with NFPA 72.

2022 NFPA 72 Section 18.4.6.3*
Audible appliances provided for the sleeping areas to awaken occupants shall produce a low frequency alarm signal that complies with the following:

(1) The waveform shall have a fundamental frequency of 520 Hz +/- 10 percent.
(2) The notification equipment shall be listed for producing the low frequency waveform.

What does NFPA 72 consider a sleeping area?

To answer this question, you need to consult NFPA 72 2022 Annex A.18.4.6.3.

"The intent of this section is to require the use of the low frequency signal in areas intended for sleeping and in areas that might reasonably be used for sleeping. For example this section requires a low frequency audible signal in a bedroom of an apartment and also in the living room area of an apartment as it might have sleeping occupants. However, it would not be required to use low frequency signal in the hallways, lobby, an other tenantless spaces. In hotels, the quest rooms would require audible signals could use any listed audible appliances regardless of the frequency content of the signal being produced. This chapter of the code addresses notification appliances connected to and controlled by a fire alarm or emergency communications system. This chapter does not address dwelling unit protection such as smoke alarms and their audible signal characteristics. Requirements for single and multiple station alarms and household fire alarm systems can be found in chapter 29.

To sum this up, NFPA 72 considers sleeping areas as bedrooms and living rooms.

Up to point, nothing has changed in the way we design and price new fire alarm systems in group R-1 occupancies and group R-2 occupancies. With that being said, lets get to the important code change noted above.

Here is where we get to the update!

2021 International Fire Code (IFC) Section 907.5.2.1.3.2

In sleeping rooms of Group R-1 and R-2 occupancies that are required by Section 907.2.8 or 907.2.9 to have a fire alarm system, the audible alarm signal activated by single or multiple-station smoke alarms in the dwelling unit or sleeping units shall be a 520-Hz signal complying with NFPA 72.

Where a sleeping room smoke alarm is unable to produce a 520-Hz signal, the 520-Hz alarm signal shall be provided by a listed notification appliance or a smoke detector with an integral 520-Hz sounder.

Here is the kicker. There are NO listed 120 VAC single or multiple station smoke alarms on the market with an integral 520 Hz sounder.

We all knew this was coming and surprise, here it is! If we simply the above code language, it states that the 120 VAC single and multiple station smoke alarms of group R-1 and Group R-2 occupancies must now produce a 520 Hz low frequency audible tone.

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Based on the second paragraph of Section 907.5.2.1.3.2, there are two ways to tackle this new requirement:

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(1) Use a listed 520 Hz low frequency notification appliance

If this option is selected, you can utilize the wall or ceiling mounted 520 Hz low frequency notification appliances required by the 2021 IFC section 907.5.2.1.3.1 for occupant notification in group R-1 and and Group R-2 occupancies. These should already be captured by your minimum code design. However, with a standard design in mind, these appliances will only activate via a general alarm signal. This new 2021 code section 907.5.2.1.3.2 is requiring the single and multiple smoke alarms to sound these low frequency appliances. To accomplish this an addressable monitor module could be connected to a contact on the residential unit smoke alarms. This has been done for quite some time in Group R-2 occupancies used for university dorms or specific design criteria such a Marriott's Module 14. In these cases, the addressable monitor module is in lace to supervise the in room smoke alarms. If these alarms activate, the fire alarm control unit (FACU) would receive a non-latching supervisory alarm without the activation of any occupant notification appliances. To insure the low frequency notification appliances activate via general alarm in addition to in-unit smoke alarm activation, you would need an addressable control module to isolate each residential units notification appliance circuit (NAC). This way the system can be programmed to activate the in-unit NAC control module upon general alarm (corridor, smoke detectors, elevator lobby smoke detectorss, manual pull stations, waterflow, etc.) or the addressable monitor module connected to the 120 VAC single and multiple station smoke alarms. Remember to program the control module for latching upon general alarm activation and non-latching for the in-unit residential single and multiple station smoke alarms.

Another scenario that will come up with this approach is audible tones synchroning as well as conflicting tones. If this method is used, an activated smoke alarm would sound it's internal sounder as well as the in room 520 Hz low frequency sounders. This would produce both the standard 3 KHz and 520 Hz tones in the space. Not sure if it is possible to disable the local piezo or sounder on a 120 VAC smoke alarm as this would rectify the conflicting tone issue. To top this off the new 2022 NFPA 72 standard requires audible tones to be synchronized. See section 18.4.3.3. We feel as though this could definitely produce an issue as the audible tones are produced from two different sources. Synchronizing the audible tones may be difficult or impossible.

Key takeaways for option number one:

Requires at least one addressable monitor module for each residential unit.
Requires one addressable control module for each residential unit
Requires a signaling line circuit (SLC) ran to each residential unit monitor module and control module.
Requires a 24VDC power circuit to the addressable control module.
Design the system so that each residential unit receives a separate isolated notification appliance circuit (NAC) fed from the control module noted above.
Confirm the electrical contractor is providing 120VAC single and multiple smoke alarms with dry contacts for the the capability to trip the addressable monitor module noted above.
Possible need for additional power supplies and signaling line circuit (SLC) cards depending on the base system.
Ensure the audible tones from the single and multiple stations smoke alarm internal piezo and the fire alarm system low frequency Sounders are synchronized. Per 2022 NFPA 72 section 18.4.3.3
Look into the issue of conflicting audible tones. As stated above there may be a method to disable the local piezo or sounder on the single or multiple stations smoke alarms.

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(1) Use an addressable system smoke detector with an integral 520 Hz low frequency sounder base.

If this option is selected for your design, you can replace the standard ceiling or wall mounted 520 Hz low frequency notification appliances with a low frequency sounder base connected to an addressable system smoke detector. As noted above per 2022 NFPA 72 Section A.18.4.6.3, these smoke detectors and 520 Hz low frequency sounder bases will be required in all sleeping areas which are considered bedrooms and living rooms. Like any other sounder base installation, make sure to account for the addition of a signaling line circuit (SLC) and sounder base notification appliance circuit. With this option, the electrical contractor can remove all power wiring, back boxes and single or multiple smoke alarms from their bid and installation.

Key takeaways for option number two:

Requires at least one addressable smoke detector with integral low frequency sounder base in each bedroom and Livingroom.
Requires a signaling line circuit (SLC) ran to each residential unit smoke detector.
Requires a 24VDC power circuit or notification appliance circuit (NAC) to the integral low frequency sounder base.
Depending on your fire alarm system, you may need end of line power supervision modules to supervise the loss of sounder base power.
Confirm the electrical contractor is NOT providing 120VAC single and multiple smoke alarms, 120 VAC power circuits and back boxes as this will be covered in your fire alarm design.
Possible need for additional power supplies and signaling line circuit (SLC) cards depending on the base system.

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Author note: Make sure if option number two is selected for you redesign, you still incorporate the necessary 110CD or 177CD visual appliances in the ADA (Americans with Disabilities Act) units.

This is a HUGE change to the code and we suggest you start the conversation with your architects, general contractors and electrical contractors so everyone is on the same page moving forward.

Thursday, August 3, 2017

Low Frequency Sounders for Sleeping Areas

What are Low Frequency Sounders for Sleeping Areas?

Anyone in the fire alarm design and installation industry has more than likely heard the term low frequency sounders. These newer sounders first appeared in the NFPA 72 2010 edition under section 18.4.5.3 and stated an effective date of January 1, 2014. In short these are re-designed audible appliances for sleeping areas only! Multiple studies have been performed on sleeping parties to see how they react in different scenarios. Some of the scenarios involved older individuals who have a difficulty with their hearing, others were individuals who are under the influence of narcotics. The original thought was that these people would have a difficult time awaking from a sleeping state via the standard 3 Hz sound put out by a typical mini-horn commonly found in apartment and hotel sleeping areas. The newer low frequency sounders have a square wave signal with 520 Hz plus or minus 10 percent. Below are two links to show you the difference between the two sound outputs:

Listen to a 520HZ Low Frequency Tone

Listen to a 3 KHz Standard Tone

Now that it is 2024, most of the country is currently enforcing the NFPA 72 2022 edition. If your AHJ is enforcing the 2013 version of this standard, you have been required to provide these low frequency appliances in all sleeping areas for nearly 4 years.

Are you Installing Low Frequency Sounders Correctly?

Now the same installation factors found in the NFPA 72 standard apply to low frequency sounders. They shall have a sound level of at least 15 dB over average ambient, 5 dB or maximum sound level (duration of at least 60 seconds) or 75 dB whichever is highest. Now seeing that NFPA 72 2013 has been nice enough to provide us with a chart depicting average ambient sound levels for different types of occupancies, this cannot be used in lieu of actual readings taken at the site. However we can take away from this chart that a residential occupancy has an average ambient sound level of 35 dB. If we use this as an example and tack on the additional 15 dB per NFPA 72 2022 18.4.5.1, we only come up with 50 dB. This is 25 dB lower than the required 75 dB per the same standard section. An example of the only time you would be going higher than 75 db is a sleeping area with an average ambient sound level of 61 dB. 61 dB plus 15 dB = 76 dB. In short, 99 percent of the time, a designer will be aiming to achieve 75 dB.

Occupancy Average Ambient Sound Level NFPA 72

NFPA 72 Occupancy Average Ambient Sound Levels

Tips to keep in mind:

If you double the power to the sounder, you will gain 3 dB
The dB from the appliance is measure at 10' away. Every time you double the distance from the appliance, you loose 6 dB. Read more here.

What Exactly is a Sleeping Area?

Seems like a pretty easy question to answer right? Well I'll have you know this comes up a lot and more often than not, designers get it wrong! A sleeping area is obviously associated with a bedroom and a bedroom is not classified as such unless it has a closet. However, as defined by NFPA 72 2022 A.18.4.6.3, low frequency sounders are required for use in areas intended for sleeping (bedrooms) as well as areas that might be reasonably used for sleeping (Living Rooms). Most apartments or hotel rooms are outfitted with a comfy couch in the living room. It's not uncommon to find yourself falling asleep in this area. This is what has prompted the requirement for low frequency sounders to be installed in not only the bedrooms but the living rooms as well.

How Does this Affect my Design?

It is pretty common knowledge that these 520 Hz low frequency sounders draw a lot more current than the standard 3 Hz mini-horns. You will need to take this into effect when calculation voltage drop and battery calculations for the remote power supplies serving the areas in question. Depending on the size of the project, this may mean you need additional notification appliance circuits and remote power supplies.

Tuesday, December 20, 2016

Low Frequency Sounders for Fire Alarm Evacuation

Are Low Frequency Sounders Being Enforced by your AHJ

Is your jurisdiction enforcing the new code mandated 520 Hz low frequency sounders for fire alarm audibility yet? If so how are you tackling this new requirement? And finally did you know that the smoke alarms within the sleeping rooms and guest units do not need to meet the 520 Hz requirement?

When did this start?

System Sensor Low Frequency Sounder and Sounder Strobe

Not a lot of people are aware that this requirement was originally noted in the (2010) NFPA 72 National Fire Alarm Code section 18.4.5.3. It states "Effective January 1, 2014, where audible appliances are provided to produce signals for sleeping areas, they shall produce a low frequency alarm signal that complies with the following:
(1) The alarm signal shall be square wave or provide equivalent awakening ability.
(2) The wave shall have a fundamental frequency of 520 Hz +/- 10 percent.

Now we fast forward to 2013.

Note that the (2013) NFPA 72 Fire Alarm and Signaling Code requirements are the same found in Section 18.4.5.3

Now lets break it down. There are a lot of code sections so stay with me.

The Annex A of NFPA 72 (2013) section A18.4.5.3 lets us know that this section does not cover the audible requirements of single and multiple station smoke alarms and instructs us to consult chapter 29 for said requirements.

If you refer to Chapter 29 "Single and Multiple-Station Alarms and Household Fire Alarm Systems" section 29.3.6 it states the following: "All audible fire alarm signals installed shall meet the performance requirements of 18.4.3, 18.4.5.1, 18.4.5.2 and 29.3.8." Please notice that this section does not include section 18.4.5.3. This may lead one to believe that single and multiple station smoke alarms for dwelling units do not need to meet the new 520 Hz low frequency requirements.

The key section to pay attention to here is section 29.3.8 which states "Notification appliances provided in sleeping rooms and guest rooms for those with hearing loss shall comply with 29.3.8.1 and 29.3.8.2, as applicable."

Section 29.3.8.1 "Mild to Severe Hearing Loss. Notification appliances provided for those with mild to severe hearing loss shall comply with the following:

(1) An audible notification appliance producing a low frequency alarm signal shall be installed in the following situations:

(a) Where required by governing laws, codes, or standards for people with hearing loss.
(b) Where provided voluntarily for those with hearing loss.

(2) The low frequency alarm signal output shall comply with the following:

(a) The waveform shall have a fundamental frequency of 520 Hz +/- 10 percent.
(b) The minimum sound level at the pillow shall be 75 dba, or 15 dba above the average ambient sound level or 5 dba above the maximum sound level having a duration of at least 60 seconds, whichever is greater."

Section 29.3.8.2 "Moderately Severe to profound Hearing Loss. Visible notification appliances in accordance with the requirements of 18.5.5.7 and tactile notification appliances in accordance with the requirements of section 18.10 shall be required for those with moderately severe to profound hearing loss in the following situations:

(1) Where required by governing laws, codes, or standards for people with hearing loss.
(2) Where provided voluntarily for those with hearing loss.

What does this mean?

Low frequency sounder internal view speaker cone

If we read section 29.3.8 very carefully you will notice the word "AND" between sleeping rooms and guest rooms for those with hearing loss. This is telling us that the requirements of section 29.3.8.1 and 29.3.8.2 apply to ALL sleeping rooms including guest rooms for those hard of hearing.

How does this effect your design?

To this date there are no UL listed UBC smoke alarms that can produce an audible tone at 520 Hz. In fact the only manufacture that has a UL listed 520 Hz low frequency sounder appliance is System Sensor. This means no more mini horns in the sleeping rooms of R-1, R-2 and R-2.1 occupancies. The only way to accomplish this is by installing a System Sensor HW-LF (low frequency sounder) or addressable smoke detector with low frequency sounder base in place of all mini horns. This will give us the required 520 Hz in all sleeping areas during a general alarm condition.

How do we accomplish 520 Hz when the Single or multiple station smoke alarm is activated?

Since there is no such thing as a low frequency LISTED smoke alarm, I propose installing addressable system smoke detectors in all sleeping rooms and guest rooms. On top of this an addressable control module will need to be installed for each residential unit. The control module will then need to be wired so that it controls an individual NAC (Notification Appliance Circuit) for that particular unit. Through programming we can activate this individual control module upon activation of any smoke detectors within the unit. Lastly the control module for each unit will need to be mapped to activate during a general alarm condition. This way we are activating the in room low frequency sounders via the in room smoke detectors as well as any building wide general alarm device. This method allows us to accomplish the requirements of section 18.4.5.3 as well as 29.3.8 with listed equipment and methods.

How does this effect your final cost?

Obviously there is a lot more equipment needed to perform this requirement such as addressable system smokes and control modules. On top of this the low frequency sounders are more expensive than mini horns. Also note that the new low frequency sounders draw more current than mini horns which will decrease your total allowable appliances per NAC ultimately increasing the number of required remote power supplies.

This is going to be a huge adjustment for our industry which will ultimately comes with a large learning curve. I suggest your contact your local AHJ (Authority Having Jurisdiction) and find out what their interpretations on this subject are.

Saturday, December 17, 2016

Strobes Flash When Fire Alarm Silenced

End Users, AHJs (Authority Having Jurisdiction) and Technicians seem to think that fire alarm strobes are required to continue flashing when the fire alarm control unit or panel is silenced.

FACT #1: There is not and never has been anything in the code that requires the fire alarm visual notification appliances AKA Strobes to continue flashing once the fire alarm control panel has been silenced.

FACT #2: NFPA 72 2013 Section 10.13.2: “When an occupant notification alarm signal deactivation means is actuated, both audible and visible notification appliances shall be simultaneously deactivated."

So Why did we have Strobes Flashing when the Fire Alarm System has been Silenced?

From what information I have been able to gather, this function crept into the minds of installers and inspectors sometime in the 1980's. The thought of having strobes continue flashing while firefighters validated the alarm condition was a plus. Firefighters could communicate via their radios without the loud distraction caused by the audible signal. Lastly, individuals looking to enter a facility would see the visual appliances flashing and know not to enter due to a potential threat of a fire.

This is an argument that comes up less as time moves forward, however, some people are stuck on the ability to have strobes continue flashing during a fire alarm system silence. Please note that while NOT required by any code or standard, this can still be required within a particular building specification or City Ordinance.

The function can be done by most manufacturers and is not hard to accomplish. However, it does not make sense to have it enabled and that is why you will not find it in any code references. Strobes where brought into the code for ADA adaptability. With that said, does it make sense to leave the strobes flashing if you silence the fire alarm?

Ask yourself, "How is a deaf person affected by this feature?".

When a fire alarm system is activated, a hearing impaired individual will see the strobes flashing but NOT hear the audible tone. Once the fire alarm panel has been silenced and the audible tone is cut off, this individual has no idea the fire department is on scene, the system as been silenced and the event is being investigated. To this individual there is still an active evacuation scenario in place until the fire alarm panel has been reset.

Ask yourself, "How is a blind person affected by this feature?".

When a fire alarm system is activated, a visually impaired individual will NOT see the strobes flashing but will hear the audible tone. If the fire alarm system is silenced and the audible tone is cut off, this individual will have no idea there is still a potential treat in the building. They could potentially return to their business when in fact there is an active fire alarm investigation occurring in their close proximity. Another point noted above was the ability for flashing strobes to notify individuals to not enter a building as it is being investigated for a fire. If you are blind, you would not be aware the fire alarm system is activated and under investigation. The blind individual could potentially walk right into harmful or fatal situation.

In my mind this is why NFPA 72 2013 directly addresses this situation in section 10.13.2. If we agree to just cut off both audible and visual signals in the event of a system silence, we are not favoring or discriminating against anyone with or without a disability.

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Tuesday, December 13, 2016

Fire Alarm Requirements for Group R-1 Occupancy

Group R-1: (Residential)

Systems required to be monitored per the 2021 IFC section 907.6.6.

A manual fire alarm system (manual fire alarm boxes) that activates the occupant notification system (horns, strobes, sounders, speakers, chimes, mass notification, etc.)

Manual Fire Alarm Box Requirements:

Manual fire alarm boxes are not required if the facility is two stories or less in height and all individual sleeping units and contiguous attic and crawl spaces to the sleeping units are separated from one another and public/common spaces by a minimum of 1-hour partitions. Each sleeping unit must also have a direct exit to a public way, egress court or yard.

Manual fire alarm boxes are not required to be installed when ALL of the following conditions exist:

#1: The Group R-1 facility is equipped with an automatic sprinkler system installed in accordance with section 903.3.1.1 or 903.3.1.2.

#2: The occupant notification systems will activate upon sprinkler water flow.

#3: At minimum one manual fire alarm box is installed at an approved location.

2021 IFC section 907.2 - If the facility is provided with an approved automatic sprinkler system in which the Waterflow activates the occupant notification system a minimum of one (1) manual fire alarm box is required to be provided in an area approved by the local AHJ (Authority Having Jurisdiction).

Exceptions:

#1: The manual fire alarm box is not required for fire alarm systems dedicated to elevator recall control and supervisory service.

#2: The manual fire alarm box is not required for group R2 occupies unless required by the fire code official to provide a means for fire watch personnel to initiate an alarm during a sprinkler system impairment event. Where provided, the manual fire alarm box shall not be located in an area that is open to the public.

UL 268 Automatic Smoke Detection Requirements:

System smoke detectors shall be provided for all of the following applications:

Above control panels and power supplies
For the purpose of elevator capture
On all HVAC units over 2,000 CFM (Duct Detector)
For releasing service
Fire Smoke Dampers
Delayed egress locks

Automatic smoke detectors are required to be installed in all interior corridors serving the sleeping units.

Exception:

Automatic smoke detectors are not required to be installed in interior corridors if the building does not contain interior corridors serving the sleeping units where all sleeping units have a means of direct exit access to the exterior.

UL 217 Smoke Alarm Requirements:

Low frequency sounders for fire alarms in sleeping areas

Single or multiple station smoke alarms shall be installed in all of the following areas:

Sleeping areas.

Each room in the path of the means of egress from sleeping area to the door leading to the sleeping unit.

On each level within the sleeping unit. This includes basements. If the sleeping unit has split levels without a door separation, one smoke alarm on the upper level will suffice. Note this is only for slip level where the distance between levels is less than one full story.

Fire Alarm Notification Requirements:

520 Hz low frequency sounders shall be installed in all sleeping areas. Horns can be provided in common areas including but not limited to corridors, public restrooms, elevator lobbies, etc. Emergency voice/alarm communications systems shall be provided for high rise applications. High rise buildings are classified by the International Building Code as a structure that has occupied floors located more than 75 feet above the lowest level of fire department vehicle access.

Note: R-1 occupancies have a required amount of handicap accessible rooms that need to be provided with visible appliances. This requires sounder/strobes, horn/strobes or speaker/strobes in the sleeping rooms and living rooms as well as a strobe in the restrooms. Keep in mind that the strobe located in sleeping areas shall be 110 candela if the top of the lens is greater than or equal to 24 inches from the ceiling. If the top of the lens is 23 inches or closer to the ceiling you shall provide a setting of 177 candela. ** These visible alarms shall activate upon system smoke detectors or single or multiple station smoke alarms.

** Use the ADA Room tool found in the main menu of this application to determine the quantity of accessible rooms you need to include in your design.

Using a sound pressure meter or dB Meter, verify you comply with the following:

Public Mode Audibility: You must have 15 dB above average ambient sound level or 5 dB above the maximum sound level for at least 60 seconds whichever is greater.

Private Mode Audibility: You must have 10 dB above average ambient sound level or 5 dB above the maximum sound level for at least 60 seconds whichever is greater.

Wednesday, March 18, 2015

Pre-Wire for ADA Adaptability in R2 Occupancies

What does it mean to pre-wire for future ADA adaptability?

The 2021 International Fire Code or IFC is where we look to find out what fire alarm requirements to follow when designing systems. Specifically Chapter 9 "Fire Protection Systems". If we dive deeper into section 907, we are informed as to what is required for each occupancy group.

For this article, we will be reviewing the requirements for an "R-2" occupancy. As defined in the International Building Code or IBC, an R-2 group occupancy consists of: "occupancies containing sleeping units or more than 2 dwelling units where the occupants are primarily permanent in nature, including: Apartments Houses, Boarding House with more than 16 occupants, Convents, Dormitories, Fraternities and Sororities, Hotels (non-transient), Live/Work units, Monitories, Motels (non-transient), Vacation timeshare properties."

Since this article revolves around the requirements to pre-wire for future visual alarms, we will stay away from discussing the initiating side of the code. Full requirements for an R-2 occupancy.

International Fire Code Section 907.5.2.3.3 Pre-Wire for Group R-2

Section 907.5.2.3.3 states "In group R-2 occupancies required by section 907 to have a fire alarm systems, all dwelling units and sleeping units shall be provided with the capability to support visible alarm notification appliances in accordance with Chapter 10 of ICC A117.1. Such capability shall be permitted to include the potential for future interconnection of the building fire alarm systems with the unit smoke alarms, replacement of audible appliances with combination audible/visible appliances. or future extension of the existing wiring from the unit smoke alarm locations to required locations for visible appliances."

This is a major upgrade in comparison to a group R-1 occupancy such as Hotels and Motels. In these facilities, the code gives us parameters as to how many rooms with visible alarms are needed based on the total quantity of sleeping units.

"So what does all this mean?"

In basic terms all living spaces within a group R-2 occupancy must contain the necessary wires, raceways and boxes to support the ability to upgrade to audible and visual notification throughout. ADA aside, our design must provide at least 75 dB in all areas of the quest room. On top of this, your jurisdiction may now be requiring the fire alarm occupant notification to produce a 520Hz low frequency tone in all sleeping areas. Find out more about 520Hz requirements.

A lot of fire alarm designers are confused to the actual requirements of this code section. To be clear, it is the intent of the code to have a fully functional low frequency audible occupant notification system that can be upgraded with visual alarms without cutting walls, adding boxes or running new conduit. All of the necessary wire or a conduit raceway must be in place to all living spaces, sleeping rooms and bathrooms within each living space. As stated in the paragraph above, we need a minimum of 75 dB throughout the space. To achieve this, it's typical to have a low frequency audible appliance in each sleeping room as well as the living space. This design makes it easy to just swap out the low frequency sounder appliance for a combination low frequency and visual appliance. Don't forget that you will need a box and wire to each restroom within the guestroom.

ADA section 4.28 "Alarms" gives us the requirements for visual appliances within ADA compliant areas. Pay close attention to section 4.28.4 "Auxiliary Alarms" Units and sleeping accommodations shall have visual alarms connected to the building emergency alarm system or shall have a standard 110-volt electrical receptacle into which such an alarm can be connected and a means by which a signal from the building emergency alarm system can trigger such an auxiliary alarm. When visual alarms are in place the signal shall be visible in all areas of the unit or room. Once a group R-2 living unit is upgraded to meet ADA requirements for visual alarms, you will need a low frequency audible tone of at least 75 dB throughout as well as visual alarms in all areas of the living unit. This includes restrooms.

Side note: NFPA 72 2022 Table 18.5.5.10.3 informs us of the candela rating required visual appliances installed in sleeping areas.

Distance from the ceiling to the top of the visual appliance lens:
> or = to 24 inches = 110 Candela
< 24 inches = 177 Candela

This standard was put in place as smoke migrates to the ceiling in the event of a fire. It is common sense that a more intense strobe flash would be required to shine thorough the thicker smoke found closer to the ceiling and still have the ability to awake a sleeping occupant. This is why we are required to install a 177 candela strobe when located less than 24" from the ceiling.

Best installation method to accomplish ADA adaptability for Group R-2 occupancies.

Run a trunk run down the corridor with Notification Appliance Circuit (NAC) loops as well as a Signaling Line Circuit (SLC) pulled into a J-Box within the closet of each living unit. It is best to pick the closet that contains the unit's breaker panel. From this J-Box pull your notification circuit loop through all appliance locations. In the event the room needed to become adaptable, simply splice your incoming/outgoing NAC loop through in the J-Box. This way the notification field wiring loop within the living unit is separate from the rest of the existing building NAC circuits. Install a single output remote power supply listed for fire within the closet and power up with a dedicated 120 AC circuit. Use the SLC in the closet to install an addressable smoke detector and control module to protect and activate the power supply. See the example layout below:

Group R-2 ADA Adaptability for Fire Alarm

Now keep in mind that these audible / visual notification appliances will need to activate via general alarm, floor alarm or an alarm from within the unit itself. To activate the notification appliances from within the living unit, you could either install addressable system smoke detectors or connect addressable mini modules to the 120 VAC UBC smoke alarms. The detectors or modules would activate the control module connected to the power supply as well as indicate a supervisory condition on the fire alarm control unit (FACU).

Tuesday, March 17, 2015

Are Low Frequency Sounders Required by Your AHJ

520Hz Low Frequency Sounders

"Effective January 1st 2014, audible appliances provided for the sleeping areas to awaken occupants shall provide a low frequency alarm signal that complies with the following: (1) The alarm signal shall be square wave or provide equivalent awakening ability. (2) The wave shall have a fundamental frequency of 520 Hz +/- 10 percent."

We got a glimpse of the future requirement in the 2010 Version of NFPA 72 section 18.4.5.3 page 102. Here we could see that come January 1st 2014, there would be a requirement for fire alarm designers to use a 520Hz square wave low frequency sounder within all sleeping areas. There have been multiple studies performed that validate the belief that a 520 Hz low frequency audible tone will have a greater chance at awakening a sleeping occupant. The lower frequency also has greater chances of awakening people whom are intoxicated or hard of hearing.

Lets fast forward to the 2016 edition of the standard. NFPA 72 version 2016 notes the same requirement in section 18.4.5.3 page 112.

Click to listen to a 520Hz Low Frequency sound file. Or a 3KHz tone typically used prior to 520Hz requirements.

Now, here we are in the year 2016 and yet not everyone is following this standard. You may ask yourselves why is our AHJ or authority having jurisdiction not requiring our fire alarm installation company to install the new 520Hz low frequency sounders for sleeping areas. Keep in mind that the particular state you install fire alarms in may have an older code adopted. Click to learn the difference between fire alarm codes and standards.

How do you know if your state or region is requiring 520Hz low frequency sounders?

The International Fire Code or IFC 2018 edition chapter 80 as well as the International Building Code or IBC 2018 edition chapter 35 both reference NFPA 72 2019. With this said, you will need to find out if your jurisdiction has adopted the 2012 or newer version of the IBC or IFC code. Better yet, System Sensor has provided a detailed map of the States and Regions currently adopting this code. See below:

Tuesday, April 22, 2014

Fire Alarm Requirements for Group R-4 Occupancy

Group R-4: (Residential)

Systems required to be monitored per the 2021 IFC section 907.6.6.

A manual fire alarm system (pull stations) and automatic smoke detection system that activates the occupant notification system (horns, strobes, sounders, speakers, chimes, mass notification, etc.)