Requirements for spacing between containers in energy storage power stations

Specifically, we're focused on spacing requirements and limitations for energy storage systems (ESS). NFPA 855 sets the rules in residential settings for each energy storage unit—how many kWh you can have per unit and the spacing requirements between those units. First, let's start with the language, and then we'll explain what this means.

Individual ESS units shall have a maximum stored energy of 20 kWh per NFPA Section 15.7. NFPA 855 clearly tells us each unit can be up to 20 kWh, but how much overall storage can you put in your installation? That depends on where you put it and is defined in Section 15.7.1 of NFPA 855.

he Installation of Stationary Energy Storage Systems—providesmandatory requirements for, and explanations of, the safety strategies and features of energy storage systems (ESS). Applying to all energy storage technologies, e standard includes chapters for specific technology classes. The depth of this standard makes

Therefore, if you install multiple storage units, you have to space them three feet apart unless the manufacturer has already done large-scale fire testing and can prove closer spacing will not cause fire to propagate between adjacent units.

In Section 15.5 of NFPA 855, we learn that individual ESS units shall be separated from each other by a minimum of three feet, unless smaller separation distances are documented to be adequate and approved by the authority having jurisdiction (AHJ) based on large-scale fire testing.

The diagram shows that each ESS unit can have a maximum rating of 20 kWh, and if you're going to install two units, let's say outside on your wall, you need to have the appropriate spacing between those units and three-feet separation from doors and windows per NFPA 855 15.6.1.