What the 2024 IFC Section 1207.5 Requires for Means of Egress Separation in Energy Storage Systems

The potential of energy storage system (ESS) failure impacts an ESS’s siting location, especially in relation to building egress. Were an ESS to be positioned too close to an exit, occupants evacuating in an emergency scenario could face a compromised path at the moment they need it most. International Fire Code (IFC) section 1207.5.8 addresses this directly by establishing minimum separation requirements between an outdoor ESS installation and any means of egress. 

Getting means of egress clearance distance right requires a thorough understanding of how multiple code sections interact, and as an engineering firm specializing in the solar and storage industry, Mayfield Renewables sets the standard by working with installers and designers to address exactly that from the earliest stages of design

Key Takeaways

• The base code language establishes that outdoor ESS installations must maintain a minimum of 10 feet from any means of egress.
• The 10-foot minimum can be reduced with both fire code official approval and large-scale fire testing.
• A reduction to 5-foot separation is possible per IFC 1207.8.4, excluding where a door serves as a means of egress.  
• Always identify your site’s means of egress before finalizing ESS placement and coordinate with the AHJ early. 

Understanding IFC 1207.5.8 

IFC 1207.5 establishes the overarching requirements for electrochemical energy storage systems, covering everything from size and separation of ESS groups, maximum allowable quantities by technology type, elevation restrictions, fire detection, fire suppression, enclosure size limits, and vegetation control. Taken together, these subsections create a comprehensive framework for how ESS installations are sized, arranged, and protected. Each subsection addresses a specific dimension of risk, and 1207.5.8 is no different.

Section 1207.5.8 applies to ESS located outdoors and in open parking garages, and it establishes a minimum separation distance between those systems and any means of egress. The code requires that this distance be determined by the fire code official based on what is necessary to ensure safe egress under fire conditions, with an absolute floor of no less than 10 feet. In practical terms, this means 10 feet is the starting point, not a suggestion, and the authority having jurisdiction may require more depending on the specifics of the installation.

What Is Means of Egress Separation?

The 2024 IFC defines a means of egress as “a continuous and unobstructed path of vertical and horizontal egress travel from any occupied portion of a building or structure to a public way. A means of egress consists of three separate and distinct parts: the exit access, the exit and the exit discharge.”. So means of egress separation, in the context of ESS installations, refers to the clearance distance between an ESS and this three-part understanding of egress.

Again, the concern is not simply proximity to a door or walkway under normal conditions, but more so during abnormal conditions. If an ESS sited too close to a means of egress is involved in an incident the route that occupants depend on to evacuate safely can be compromised or even unusable at the worst possible moment. 

The Exception

The 10-foot minimum is not absolute. The fire code official is authorized to approve a reduced separation distance if the manufacturer can demonstrate through large-scale fire testing, see IFC 207.1.7)  that a fire involving the ESS will not adversely impact occupant egress at the proposed reduced dstance. This places the burden of proof on the manufacturer, and the reduction is only valid once the fire code official has reviewed and accepted the test results. Without that approval, 10 feet remains the enforceable minimum regardless of what a manufacturer may claim about their system's performance.

Exterior Wall Installations: Where It Gets Complicated

Section 1207.8.4 permits ESS units to be installed outdoors on exterior walls of buildings, but only when a specific set of conditions are met. Individual units are capped at 20 kilowatt hours, which effectively limits these installations to residential-scale applications. Units must comply with the broader requirements of Section 1207, be installed in accordance with the manufacturer's instructions and their listing, and be separated from each other by at least 3 feet. 

They must also maintain a minimum of 5 feet of separation from doors, windows, operable openings into buildings, and HVAC inlets. As with other spacing requirements throughout 1207, the exception allows the fire code official to approve smaller separation distances for both the 3-foot between battery units, and the 5-foot from total BESS footprint to egress requirements where large-scale fire testing supports it. 

The 5-foot separation from doors is where 1207.8.4 and 1207.5.8 come into direct conflict. If a door on the exterior wall of a building also serves as a means of egress, the 5-foot requirement in 1207.8.4 does not satisfy the 10-foot minimum established in 1207.5.8. Design and installation cannot assume reduction to 5-foot simply. The more stringent requirement takes precident. if the door functions as a means of egress.

When 5 Feet Becomes 10 Feet

When a door on the exterior wall serves as a means of egress, the 5-foot requirement for a wall-mounted BESS in 1207.8.4 is not sufficient on its own. Section 1207.5.8 establishes 10 feet as the absolute minimum separation from any means of egress, and that requirement does not disappear simply because the installation is wall mounted. 

For example, a wall-mounted ESS unit placed 7 feet from an exit door would satisfy 1207.8.4 but violate 1207.5.8. The designer or installer must identify whether each door near the installation qualifies as a means of egress and apply the 10-foot minimum accordingly, unless the fire code official has approved a reduced distance based on compliant large-scale fire testing. 

How to Determine if a Door is a Means of Egress

Determining whether a door qualifies as a means of egress requires looking at its function within the building's overall egress system. Under IBC Chapter 10, a means of egress is made up of three components: the exit access, the exit, and the exit discharge. A door that forms part of any one of these three components is a means of egress door. This includes doors that lead occupants from an occupied space toward an exit, doors that serve as the exit itself, and doors that discharge occupants to a public way. A door providing access only to a mechanical room, storage area, or other non-occupied space is generally not part of the means of egress system.

The most reliable way to confirm which doors on a building are designated as means of egress is to consult the architectural drawings, which are required to identify egress components under IBC Chapter 10. Where drawings are unavailable or ambiguous, coordinating directly with the authority having jurisdiction is the appropriate path. When assessing an exterior wall ESS installation, every door within proximity of the proposed unit should be evaluated before finalizing placement. If any of those doors serve as exit access, an exit, or exit discharge, the 10-foot separation requirement under 1207.5.8 governs, and the 5-foot figure in 1207.8.4 alone is not sufficient.

Conclusion

Egress separation is rarely the first thing that comes to mind when planning an ESS installation, but as 1207.5.8 makes clear, it carries the same weight as any other spacing requirement in the code. The interaction between 1207.5.8 and 1207.8.4 is a useful reminder that no single code section exists in isolation. A spacing distance that satisfies one requirement may fall short of another, and the consequences of getting it wrong extend beyond a failed inspection. When a means of egress is compromised during a thermal runaway event, the stakes are measured in occupant safety, not just code compliance. Reading these sections together, identifying egress components early in the design process, and coordinating with the authority having jurisdiction before installation are the most effective ways to ensure that the spacing decisions made on paper hold up when it matters most. 

Mayfield Renewables is an engineering consultancy specializing in commercial and industrial PV and microgrid engineering. Contact us today for a consultation.

FAQs

Does 1207.5.8 apply to all outdoor ESS installations?

Yes. Section 1207.5.8 applies to all ESS located outdoors and in open parking garages, regardless of occupancy type or system size. Any outdoor installation must maintain a minimum of 10 feet from any means of egress unless a reduced distance has been approved by the fire code official based on compliant large-scale fire testing.

Can the 10-foot minimum ever be reduced?

Yes, but only under specific conditions. The fire code official is authorized to approve a reduced separation distance if large-scale fire testing conducted in accordance with UL 9540A and Section 1207.1.7 demonstrates that a fire involving the ESS will not adversely impact occupant egress. That approval must come from the authority having jurisdiction before any reduction can be applied.

Does the 5-foot separation in 1207.8.4 satisfy the egress requirement for exterior wall mounted units?

Not when the door in question is a means of egress. The 5-foot separation in 1207.8.4 governs doors, windows, operable openings, and HVAC inlets, but it does not override 1207.5.8. Where a door serves as exit access, an exit, or exit discharge, the 10-foot minimum in 1207.5.8 applies regardless of the installation type.

How do I know which doors on a building qualify as means of egress?

The building's architectural drawings are the most reliable reference, as they are required to identify egress components under IBC Chapter 10. Where drawings are unavailable or unclear, coordinating with the authority having jurisdiction is the appropriate course of action prior to finalizing ESS placement.

Does the 20 kWh cap in 1207.8.4 apply to all outdoor ESS installations?

No. The 20 kWh limit applies specifically to ESS units mounted on exterior walls under 1207.8.4. Outdoor installations that are not wall mounted, such as pad mounted systems, are subject to the broader requirements of Section 1207 and are not restricted to 20 kWh under this particular provision.