# Residential ESS (battery back-up) Heat Detectors Required?



## Joe.B (Oct 26, 2021)

I posted this in the Res. forum because the most useful information I'm finding comes from chapter 3 of the Res code, hoping someone can shed some light on this for me. 

We have had an influx of questions regarding "*satisfying the new heat detector requirement*." It appears as though some of my neighboring AHJ's are requiring heat detectors for all new battery installations. I am not seeing anything that would indicate a blanket requirement for heat detectors. I'm just wondering if I'm missing something. For example are they looking at the 2020 NEC and finding requirements that are not yet adopted here in CA? Any insight is greatly appreciated. Here's what I've found so far:

We are on 2019 CA Codes, based off of 2018 IBC/IRC/IFC and 2017 NEC

I've read through CRC R327, CEC (NEC) 705 & 706, and CFC 1206 and this is all I can find:

R327.7 Fire Detection

Rooms and areas within dwelling units, basements, and attached garages in which ESS are installed shall be protected by smoke alarms in accordance with Section R314. *A listed heat detector shall be installed in locations within dwelling units and attached garages where smoke alarms cannot be installed based on their listing.*

CFC 1206 is only triggered when the allowable quantities are exceeded by:

R327.5 Energy Ratings

Individual ESS units shall have a maximum rating of 20 kWh. The aggregate rating of the ESS shall not exceed:
40 kWh within utility closets, basements, and storage or utility spaces.
80 kWh in attached or detached garages and detached accessory structures.
80 kWh on exterior walls.
80 kWh outdoors on the ground.
*ESS installations exceeding the permitted individual or aggregate ratings shall be installed in accordance with Sections 1206.1 through 1206.9 of the California Fire Code.*

And states:

1206.5.4 Fire Detection

An approved automatic smoke detection system or radiant energy—sensing fire detection system complying with Section 907.2 shall be installed in rooms, indoor areas, and walk-in units containing electrochemical ESS. An approved radiant energy—sensing fire detection system shall be installed to protect open parking garage and rooftop installations. Alarm signals from detection systems shall be transmitted to a central station, proprietary or remote station service in accordance with NFPA 72, or where approved to a constantly attended location.


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## steveray (Oct 27, 2021)

2021 IRC

R328.7 Fire detection. Rooms and areas within dwelling
units, basements and attached garages in which ESS are
installed shall be protected by smoke alarms in accordance
with Section R314. A heat detector, listed and interconnected
to the smoke alarms, shall be installed in locations
within dwelling units and attached garages where smoke
alarms cannot be installed based on their listing.


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## Joe.B (Oct 27, 2021)

Apparently smoke alarms are not rated for garages therefore heat detectors required. I didn't know that because locally our fire departments recommend smoke alarms in garages, in fact they give them out for free and install them in garages all the time and have told me it's saved houses. We don't get hot here.

Thanks!


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## Msradell (Oct 27, 2021)

Joe.B said:


> Apparently smoke alarms are not rated for garages therefore heat detectors required. I didn't know that because locally our fire departments recommend smoke alarms in garages, in fact they give them out for free and install them in garages all the time and have told me it's saved houses. We don't get hot here.
> 
> Thanks!


There are 2 reasons that smoke detectors are not recommended for garages. The 1st 1 you alluded to is that in many areas garages get quite warm in the summer. The 2nd 1 is that many times he exhausts from automobiles will trigger them accidentally. I would certainly recommend installing a heat detector any place there was a ESS is installed.


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## tmurray (Oct 28, 2021)

Yes, we had a local home inspector going around calling for smoke alarms in garages. He said it was required by code. We had a bunch of people with new homes get upset that their brand new home does not meet code. So we asked him for a code section. When he couldn't find one, he changed to "it is good construction practice". When we showed him that the Canadian installation standard and manufacturer's installation instructions prohibited their installation in that location, he finally dropped it.


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## tmurray (Oct 28, 2021)

Msradell said:


> There are 2 reasons that smoke detectors are not recommended for garages. The 1st 1 you alluded to is that in many areas garages get quite warm in the summer. The 2nd 1 is that many times he exhausts from automobiles will trigger them accidentally. I would certainly recommend installing a heat detector any place there was a ESS is installed.


Cold will actually will cause nuisance alarms and degrade the effectiveness of the equipment as well, so it is a no go anywhere.


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## Glenn (Oct 28, 2021)

This is a rapidly changing subject, with new standards having just been created and likely more underway.  There is a new marking "for use in residential dwelling units" part of the UL 9540 standard.  These units are a complete 100% exception for everything in R328, including heat detectors.  These units are incapable of going into thermal runaway, even with physical damage.  So none of the vehicle protection is required either.  I did some heavy research on the 2021 changes for this recent article in my Fine Homebuilding Magazine column, Know the Code.  Lots of nuggets in the article, and I am happy to further discuss them.  https://www.finehomebuilding.com/2021/06/04/storing-your-own-electricity


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## Joe.B (Oct 28, 2021)

Great article Glenn. I recently did a site visit for a contractor who wanted to look at a garage with me before he gave a bid to the customer. This was an attached garage with exposed framing except for the wall that separated the house which had 5/8" gwb (foundation to roof decking) and the door into the house was spring loaded. He was concerned that he was going to have to bid the job to include finishing the wall board in the entire garage. I haven't seen an application yet but I anticipate seeing it soon. 

The main points I stated at the time was the house was built to code at the time it was built and that he would have to carefully read the installation directions for the install. I also said that I would have to do a careful plan-check based on what he submits. So basically I told him that I didn't know.

So given this garage scenario and assuming the batteries were installed on the wall with gwb to manufactures specs, and the proper heat detector were installed do you think covering the rest of the framing with gwb would be required? If not required do you think it would be a good recommendation? Or not worry about that as long as instructions were followed? 

Thanks again for sharing your knowledge.


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## Glenn (Oct 28, 2021)

Joe.B said:


> Great article Glenn. I recently did a site visit for a contractor who wanted to look at a garage with me before he gave a bid to the customer. This was an attached garage with exposed framing except for the wall that separated the house which had 5/8" gwb (foundation to roof decking) and the door into the house was spring loaded. He was concerned that he was going to have to bid the job to include finishing the wall board in the entire garage. I haven't seen an application yet but I anticipate seeing it soon.
> 
> The main points I stated at the time was the house was built to code at the time it was built and that he would have to carefully read the installation directions for the install. I also said that I would have to do a careful plan-check based on what he submits. So basically I told him that I didn't know.
> 
> ...


Thank you.  Section R328.4 item #2 of the 2021 IRC simply requires the gypsum separation of 302.6.  So it sounds good to me so far.  Of course the first thing is they need to select the ESS they are using.


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## Joe.B (Oct 28, 2021)

Glenn said:


> Thank you.  Section R328.4 item #2 of the 2021 IRC simply requires the gypsum separation of 302.6.  So it sounds good to me so far.  Of course the first thing is they need to select the ESS they are using.


Right, I figure they're working that out now. I'll come back to this post with an update when I finally see this permit come in.


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## Joe.B (Oct 28, 2021)

Also an update to this Heat Detector requirement I did an inspection for a Sunpower battery system in a garage yesterday and the house already had an alarm system so it was very easy for the contractor to install a new heat detector in the garage that ties into the existing alarm. That was awesome for them!


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