How have people been addressing the IFC (2021) Section 907.5.2.1.3.2 requiring 520Hz single/multiple station smoke alarms in residential units being addressed?
It sounds like there are no 520 Hz smoke alarms available on the on the market meet these requirements. We have a roughly 300-unit building and the AHJ is pushing us to put smoke detectors with sounder bases in each unit instead of 120v smoke alarms. We know this could be done, but the cost impacts would be substantial and the future maintenance and inspections in the building would be very difficult. This is the first time we've seen this be pushed by an AHJ, so looking for information on how others have handled this. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
13 Comments
Chad
7/26/2024 08:31:36 am
That’s the only solution right now until they make smoke alarms with LF sounders
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Ricardo Gonzales Jr
7/26/2024 08:54:59 am
There are smoke alarms with the 520Hz available. However, they are more expensive than the older version.
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Chad
7/26/2024 09:00:10 am
Ricardo,
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Ricardo Gonzales Jr
8/14/2024 09:11:27 am
I saw them at Home Depot, but when I look on-line, they don't show up. I haven't been back in a few weeks. I'll stop there and see if they have them and take pictures.
Jack G
7/26/2024 09:19:26 am
They are not available in my 3 areas that I work in. Online companies that have them on their menu are out of stock.
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Jay
8/5/2024 02:44:03 pm
The requirement for low frequency square wave audible notification in sleeping areas was first introduced in the 2010 edition of NFPA 72, with an effective date of January 1, 2014. The manufacturers were first given a 3 year window to develop a solution and have now had over 14 years.
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Sean
7/26/2024 10:02:01 am
Here was a good article from Jensen Hughes that may be worth sharing with the AHJ or customer. It's from 7 months ago and notes the technology doesn't exist yet, and I've heard that there are outfits trying to develop 120V LF Smoke Alarms, however I am not aware of a product yet. The discussion may go towards justifying the additional cost to include it on the building fire alarm system.
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Brian
7/26/2024 05:57:42 pm
As a third-party acting as the AHJ for several jurisdictions, we basically have not enforced this requirement. Those that have seem to regret go back to the tried and true design.
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Katie
8/15/2024 04:29:55 pm
As a member of the AHJ we have added language (amendment) to Section 907.5.2.1.3.2 to read: shall be a 520-Hz signal complying with NFPA 72 or an alternative means approved by the fire code official. Until technology catches up, we allow the 120v single/multi-station just like in a single-family dwelling. That way we are not just blatantly not enforcing a code we adopted.
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Chad
8/15/2024 04:32:53 pm
As an AHJ, I understand and acknowledge that local amendments are necessary evil. We use a few. It’s just unfortunate that the standard has changed so drastically and we’re not all on the same page, Nationally. Many places are enforcing this full throated.
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Chad
8/15/2024 04:38:25 pm
I’ve heard that Kidde and BRK have no intention of pursuing the development one of these devices. It’s not practical to run one on a 9 V battery. My fear is the technology will never catch up.
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Taylor
1/14/2025 02:49:51 pm
We are attempting a solution that minimizes complexity to the fire alarm system itself.
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Ricardo Gonzales Jr
1/14/2025 03:33:22 pm
As the comments above indicate the 520Hz devices require a lot more power to operate. This would be consistent with audio systems where the low frequencies draw more power over the same time frame than higher frequencies. i.e. LF vs. Voice. A 9V smoke alarm would have one activation and then the battery would need replacing. LF is a power hog.
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