Building and Fire Codes for Data Centers: IBC, NFPA 75 and 76, NFPA 855

Building and fire codes in the United States are model codes that states and local governments adopt, usually with amendments. The International Building Code is adopted in all 50 states, and the International Fire Code, or major portions of it, in 42 states plus the District of Columbia, Puerto Rico and Guam.⁵ Most states do not adopt the codes verbatim; they adopt sections and add local exceptions.⁵ The edition matters, because requirements for batteries in particular have changed quickly from one edition to the next.

Codes rarely decide whether land can hold a data center, but they shape what fits on it. Fire separation, generator placement, fuel quantities, fire access and battery rooms all take space and drive the layout that goes into site plan review. They also feed the building permit stage described in the data center permitting process.

Occupancy classification sets construction type, allowable area, egress, sprinkler and separation requirements. The 2024 IBC defines “data center” in Section 202 but does not assign it to an occupancy group in Chapter 3, so code officials classify each facility based on its use, hazards and risk.¹

Classification has practical costs. An architecture firm notes that jurisdictions often ask for Group B across the whole building at first, and that applying Group B to server halls can force design for an occupant count far above the real operating headcount.⁸ Facilities with lithium-ion energy storage are identified as Group F-1 under the 2024 IBC, so battery rooms may need separation from the rest of the building.¹ A written code analysis agreed with the building official before design development is the way to settle these questions.

NFPA 75 is the standard for fire protection of information technology equipment and addresses data centers and the areas around them.² NFPA 76 covers telecommunications facilities that deliver landline, cable, wireless and satellite services to the public, including cable entrance areas, power areas and standby engine areas.⁹ A common dividing line is private versus public networks: NFPA 75 for an operator’s own IT equipment, NFPA 76 for carrier equipment serving the public. Colocation sites and carrier hotels often contain both, so designers look at both standards.²

The National Electrical Code ties in through Article 645, which covers information technology equipment rooms. Article 645 is optional. It grants wiring allowances, such as cabling under raised floors, only when conditions are met, including a disconnecting means under Section 645.10, dedicated or coordinated HVAC, restricted occupancy and fire-resistant separation.¹⁰ Compliance with NFPA 75 is needed only when an owner wants those allowances.¹⁰ Many large data halls are wired under standard methods instead, which avoids the room-wide disconnect.

Uninterruptible power supply (UPS) batteries are where data center fire codes have changed most. NFPA 855 governs stationary energy storage systems, and through the IFC’s energy storage provisions it applies to lithium-ion UPS systems that exceed its threshold, commonly read as 20 kWh of lithium-ion storage per fire area.⁶ That threshold is low enough to catch nearly every data hall UPS line-up and any on-site battery energy storage system.

Larger battery groups need test evidence. For energy storage groups over 50 kWh, NFPA 855 requires sprinkler design and separation distances to be validated by large-scale fire testing, such as UL 9540A or equivalent, and a fire authority’s review of the 2026 edition notes that sprinkler density is to be based on that large-scale test.³ Trade reviews of the 2026 edition also highlight new thermal runaway propagation prevention provisions and expanded commissioning requirements.¹¹ Which edition governs depends on the fire code a jurisdiction has adopted, so confirm it with the fire marshal before selecting a battery product.

The September 2025 fire at South Korea’s National Information Resources Service in Daejeon shows why regulators focus on batteries. It began with a lithium-ion UPS battery during a relocation, destroyed all 384 battery packs in a fifth-floor IT room and flared again after it was first put out.¹² The building hosted servers for 647 government systems, and restoration came in phases.¹³ For the power side of on-site storage, see microgrids and battery storage.

Backup generators bring three groups of rules. NFPA 110 and the NEC set the baseline for reliability and operation of emergency and standby power systems, while NFPA 37 governs how the engine and its fuel supply, tanks and surroundings are installed so they do not create a fire hazard.⁴ Fuel tanks follow NFPA 30 and related standards where NFPA 37 points to them.⁴

• Indoor fuel limits: a fuel tank that is not in a room by itself is limited to 660 gallons under NFPA 37, and NFPA 110 caps integral tanks inside or on a roof at the same amount.⁴
• Generator rooms: one California hospital agency’s checklist requires sprinklers and bars combustible materials when fuel storage exceeds 660 gallons of Class II liquid.¹⁴
• Spill planning: a facility with more than 1,320 gallons of aboveground oil storage, counting only containers of 55 gallons or more, needs a federal SPCC plan if a spill could reach navigable waters.⁷
• Plan tiers: facilities with 10,000 gallons or less, and no single tank over 5,000 gallons, may qualify for simpler self-certified plans.⁷

Most campus generators sit outdoors on sub-base tanks, which avoids the indoor limits but brings setback, fire access and spill containment questions at site plan review. Fuel quantity is a design choice driven by required runtime; see backup generators and fuel sizing. Emissions are a separate approval, covered in air permits for data center generators.

Most large data centers are fully sprinklered, often with pre-action systems in data halls, and some add clean-agent suppression in critical rooms. The fire code official also reviews fire alarm, smoke detection, fire department access, hydrants and water supply. Water supply ties back to the site: fire flow can drive the size of the water main or require on-site storage, which is a question for municipal water and sewer capacity.

Fire officials have also become more cautious about lithium-ion batteries and diesel generators together. The New South Wales fire service, for example, has published a position statement on both in data centers, including sprinkler and separation expectations for battery groups.³

1. 01Which IBC and IFC editions the state and locality have adopted, and any local amendments.⁵
2. 02How the building official has classified other data centers, and whether lithium-ion areas have been treated as F-1.¹
3. 03The fire marshal’s position on battery rooms, large-scale fire test data and separation.³
4. 04Whether fire flow is available from the public system or needs on-site storage.
5. 05How much fuel the campus will store, and what that triggers for SPCC and local permits.⁷
6. 06Whether outdoor generator and battery yards fit within setbacks and leave room for fire access.

None of this is usually decisive at the land stage, but it shapes layout, cost and schedule, and a jurisdiction that has never reviewed a data center may take longer. If you want an early read on a parcel, you can get a site reviewed.