A Look at NFPA 855: Locations for Energy Storage in One- or Two-Family Dwellings

The US energy storage market saw a dramatic 84% surge in installed capacity during Q1 2024 compared to the same period in 2023, as reported in the June 2024 US Energy Storage Monitor from Wood Mackenzie and American Clean Power. This substantial growth highlights the increasing importance of energy storage systems (ESS) across all segments. As the industry expands, it’s crucial for installers and designers to familiarize themselves not only with the National Electrical Code but also with other key compliance documents. One such critical resource is NFPA 855, Standard for the Installation of Stationary Energy Storage Systems (2023).

In this excerpt from 2023 NFPA 855 and Fire Codes for Energy Storage Systems course, HeatSpring instructor Ryan Mayfield explains the acceptable locations for ESS in one- and two-family dwellings, as outlined in Chapter 15 of NFPA 855. For a comprehensive understanding of energy storage installation requirements, consider enrolling in Ryan’s 2023 NFPA 855 and Fire Codes for Energy Storage Systems course, which covers an in-depth look of the 2023 NFPA 855 standards and related fire codes. 

Looking at that kind of visual part of 15.3. We have this illustration showing the requirements that we have for our installs. So we have three feet in between the equipment, so that’s our code language. That’s our charging statement. Unless we have documentation saying otherwise, we would have to have a minimum of three feet between our pieces of equipment. As we’re going to see, the requirements are three feet from windows and doors that open into the dwelling units. So it’s important to know that as well in keeping our equipment spaced far apart. 

As we all know when you go to a job site, when you’re at your customer’s home, space can very much be at a premium and being able to fit this equipment in under all of the requirements – it can get difficult sometimes. So just knowing what these are and understanding what documentation you need to do any variants from these requirements is important. 

So here’s that [section] 15.4.1, where [it states] that three feet from doors and windows directly entering the dwelling unit. That’s a change in the 2023 language, and so understanding that if those windows or doors are directly into the dwelling unit, then we have to have that minimum of three feet. That’s one of those four requirements. 

But the other things – and this is a question that comes up a fair amount is –  where can I put the energy storage? What is allowed? 

We have these four locations that are explicitly called out – attached or detached garages. 

Attached garage is separated from the dwelling unit and sleeping units in accordance with the local building code. That’s one way. 

In a detached garage or accessory structure, those are acceptable locations. 

Outdoor wall units with that three foot requirement. 

Then we do have this in enclosed utility closets and storage or utility spaces where approved by the AHJ. So this is giving us a little bit more leeway. This is giving us a little bit more open ended in terms of where we can install these things. It doesn’t have to be in a garage or it doesn’t have to be outside. Utility spaces are acceptable, where approved by the AHJ, so they give the AHJ some leeway there. 

I highly recommend if you are an installer, if you’re a designer, if it’s at all a question in your mind, then talking with the AHJ and making sure that they do approve it as well. Just because once it’s there, it’s going to be a heck of a lot harder to move and figure out a different place. This is definitely not something worth trying to ask for forgiveness instead of permission. Definitely get permission ahead of time.