In the October 2020 issue of EC&M, we discussed the requirements for energy storage systems (ESSs) as covered by the 2020 edition of the NEC. It’s time to take another look at these systems regarding fire codes and building codes.
To address concerns expressed by fire services that have to respond to buildings in emergency situations (both fire-related and non-fire related), NFPA 1, Fire Code, and the 2021 International Fire Code (IFC) contain requirements relative to the installation of ESSs, especially in residential occupancies. In response to this, NFPA established a technical committee to develop a new standard for the installation of these systems. Note that these requirements are in addition to those found in NFPA 70, the National Electrical Code, and they are not intended to override or replace them.
Origin and development
The ESS project that led to this first edition of NFPA 855, Standard for the Installation of Stationary Energy Storage Systems, was approved by the NFPA Standards Council in April 2016, after which a call for members was posted. The original request was submitted by an individual on behalf of the California Energy Storage Alliance to address gaps in regulation identified in workshops held by the U.S. Department of Energy and the Fire Protection Research Foundation. In August of that same year, the Standards Council appointed the first NFPA Technical Committee on ESSs. The initial draft was developed over the course of three meetings by the technical committee, and it was released to the public in 2017. Over the past two years, the technical committee has met several times to review feedback from the public and make improvements to the standard.
Some of the requirements this new standard covers are as follows:
(1) Plans and specifications associated with an ESS and its intended installation submitted to the AHJ for approval.
(2) Location and layout diagram of the room or area in which the ESS is to be installed.
(3) Details on hourly fire-resistant-rated assemblies provided or relied upon in relation to the ESS.
(4) The quantities and types of ESS units.
(5) Manufacturer's specifications, ratings, and listings of ESS.
(6) Description of energy storage management systems and their operation.
(7) Location and content of required signage.
(8) Details on fire suppression, smoke or fire detection, gas detection, thermal management, ventilation, exhaust, and deflagration venting systems, if provided.
(9) Support arrangement associated with the installation, including any required seismic support.
This new standard covers ESS installations in indoor and outdoor locations and provides even more installation restrictions when installing an ESS in or at a dwelling occupancy. Indoor locations include non-dedicated-use buildings or (put another way) general-use buildings that have an ESS installed within them. There are requirements for separation from adjacent ESS assemblies and a limit of 50kWh per group assembly. Dedicated-use buildings are those that are intended for use only for containing ESS assemblies for grid-tied operations. Information is provided for what else is required, which includes items such as site access providing a means for personnel to egress from the area and limiting such personnel to those necessary to operate the installation. This adjacent use is limited to 10% of the building area.
There is a general prohibition to the installation of other than portable ESS units in sleeping rooms or living areas of dwelling units. Chapter 15 contains some more specific requirements for ESS installations associated with one- or two-family dwellings or townhouse units.
The first requirement aligns with the requirements found in the NEC, and that is the listing of the assembly in accordance with UL 9540. This listing requirement is limited to ESS equipment with a rating of 1kWh or greater in maximum stored energy. ESSs listed and labeled solely for utility or commercial use shall not be used for residential applications.
ESSs shall be installed in accordance with the manufacturer’s instructions and their listing. One thing that is different from a standard electrical installation in one of the residential applications is a requirement for a commissioning procedure, which requires the following steps:
(1) Verify that the system is installed in accordance with the approved plans and manufacturer’s instructions and is operating properly.
(2) Supply a copy of the manufacturer’s installation, operation, and maintenance instructions included with the listed system.
(3) Provide training on the proper operation and maintenance of the system to the system owner.
(4) Provide a label on the installed system that contains contact information for the qualified maintenance and service providers.
In addition, it is required to separate individual ESS units a minimum of 3 ft apart unless documented fire testing is provided that would allow for a lesser distance. This information would be provided by the manufacturer.
As far as where these units can be located in a dwelling unit setting, they are limited to the following locations:
(1) In attached garages separated from the dwelling unit living area and sleeping units in accordance with the local building code.
(2) In detached garages and detached accessory structures.
(3) Outdoors on exterior walls or on the ground located a minimum of 3 ft (914 mm) from doors and windows.
(4) In enclosed utility closets and storage or utility spaces.
If the room or space where the ESS is to be installed is not finished, the walls and ceiling of the room or space shall be protected with not less than 5∕8-in. Type X gypsum board.
An ESS shall not be installed in the living area of dwelling units or in sleeping units other than within utility closets and storage or utility spaces.
The limitation of energy ratings for these installations is as follows:
- Individual ESS units shall have a maximum stored energy of 20kWh.
- The aggregate rating amount within a dwelling, garage, or accessory structure shall not exceed:
(1) 40kWh within utility closets and storage or utility spaces.
(2) 80kWh in attached or detached garages and detached accessory structures.
(3) 80kWh on exterior walls.
(4) 80kWh in outdoor installations.
The last item we’ll cover is the fire detection that is required by NFPA 855, which is as follows:
Interconnected smoke alarms shall be installed throughout the dwelling, including in rooms, attached garages, and areas in which ESSs are installed in compliance with the local building code.
Where ESSs are installed in an attached garage or an area in which smoke alarms cannot be installed in accordance with their listing, an interconnected listed heat alarm shall be installed and connected to the smoke alarm system required by the local building code.
Summing it up
Much of this information is what NFPA 855 requires, and this article is intended to provide awareness of this new standard. Both enforcers and installers need to be aware of this standard. As with any new standard, it will take time for jurisdictions to formally adopt it into a regulatory requirement. It is recommended that installers check with the jurisdictions where they are working to see if the adoption process is either underway or complete. Those interested in this standard are encouraged to get involved in the NFPA process because this standard is subject to public review and comment just like all NFPA standards.
Jim Rogers is the owner/operator of Bay State Inspectional Agency, Vineyard Haven, Mass. He is an active instructor for IAEI, the wiring inspector for the town of Oak Bluffs, and the chair of NEC Code-Making Panel (CMP) 4. He has previously taught for the International Brotherhood of Electrical Workers (IBEW). He can be reached at [email protected].
Inspector Intel articles are provided by the International Association of Electrical Inspectors (IAEI), www.iaei.org, a membership-driven, non-profit association headquartered in Richardson, Texas, that promotes electrical safety throughout the industry by providing education, certification of inspectors, advocacy, partnerships, and expert leadership in electrical codes and standards.
