In short
Modular and prefabricated AI data centers are factory built sections that are transported to a site and assembled, rather than built entirely on the ground from raw materials. They must meet the same International Building Code (IBC) requirements as traditional construction. Factory built units also need a product safety certification under UL 2755:2025. During fabrication inside a factory, OSHA general industry standards apply. Once modules are delivered and lifted into place on site, OSHA construction standards govern. Transporting a module that is wider than 8 feet 6 inches, taller than 13 feet 6 inches, or longer than 53 feet triggers state oversize and overweight permits, often adding weeks to the schedule. About 39 states run their own modular programs that let third party inspectors approve the factory work, so that local officials only need to inspect the foundation and connections. Modular construction shortens the site timeline to 8 to 13 months compared with 24 to 36 months for traditional building, though the upfront capital cost per megawatt is 20 to 30 percent higher.
What is modular and prefabricated construction for AI data centers?
Modular construction means building major sections of a facility inside a factory, shipping them to the site, and lifting them into place. For an AI data center, these sections are not simple steel boxes. They are power modules, cooling modules, and fully integrated IT modules that arrive with servers, electrical switchgear, liquid cooling loops, and fire suppression already installed and tested.
Prefabricated AI data center solutions fall into three main build types. The first is a power module, a factory built unit that houses transformers, switchgear, and backup power equipment. The second is a cooling module, which holds chillers, pumps, and heat rejection systems. The third is an IT module, the most complex, containing racks, servers, networking gear, and often the liquid cooling distribution. A fully prefabricated approach, where all three types are combined into a complete data hall before leaving the factory, is the fastest growing segment, with a projected compound annual growth rate of 16.9 percent through 2032. MarketsandMarkets, May 2026
Some projects assemble several IT modules together on site to form a larger campus. For example, Microsoft deployed modular AI data centers across 14 global locations in 2024, averaging 13 months from contract to operation, with configurations scaling from single modules to 40-module campuses delivering 10 megawatts of AI compute capacity. OSHA 29 CFR 1926 Subpart CC, Introl, Dec. 2025 update
Another example is the Vertiv MegaMod CoolChip, launched in July 2024, which uses direct to chip liquid cooling and can support hundreds of kilowatts per row in a prefabricated enclosure. It claims to cut deployment time by up to 50 percent. [Vertiv press release, July 2024](https://www.vertiv.com/fr-ca/about/news-and-insights/corporate-news/vertiv-launches-high density-prefabricated-modular-data-center-solution—to-accelerate-global-deployment-of-ai-compute)
Why are developers turning to modular for AI data centers?
The United States market for modular data centers was valued at about $11.87 billion in 2025 and is projected to reach $30.61 billion by 2032. MarketsandMarkets, May 2026 Behind that growth are three hard facts.
First, speed. A traditional stick built AI data center takes 24 to 36 months from breaking ground to commissioning. A modular build can cut that to 8 to 13 months because foundation work and module fabrication happen in parallel. Introl, Dec. 2025 update A reference deployment by Schneider Electric reached operational status in 11 months for a 4 megawatt facility, including 320 NVIDIA H100 GPUs. Introl, Dec. 2025 update
Second, reliability. Modular construction moves most of the construction work indoors, under controlled factory conditions. Factory quality control achieves roughly 95 percent first pass quality compared with 60 to 70 percent for field construction. Introl, Dec. 2025 update Schneider Electric’s Barcelona factory runs a 400 point inspection on each module, including thermal imaging of electrical connections and pressure testing of cooling systems. Introl, Dec. 2025 update After commissioning, modular deployments reach 99.982 percent availability within the first year of operation, matching traditional builds that need 18 to 24 months of operational tuning to get there. Introl, Dec. 2025 update
Third, the existing construction pipeline is strained. Nine out of ten traditional AI data center projects face delays, with the average delay extending the timeline by 34 percent. Hyperscale projects finish on average 20 months late, and costs run 80 percent over estimates. Vertiv/Dell federal white paper Primary market vacancy rates hit a historic low of 2.8 percent in the first half of 2024. CBRE
Speed and quality come at a cost. Modular builds have a 20 to 30 percent higher capital expenditure per megawatt. A 4 megawatt modular facility costs about $40 million compared with $32 million for a traditional equivalent. However, the faster timeline lets the project start generating revenue 12 to 18 months earlier, and factory assembly cuts construction labor by about 60 percent, saving $2 to $3 million on a 4 megawatt project. Introl, Dec. 2025 update
What building codes govern modular AI data centers?
There is no separate modular building code in the United States. A modular AI data center must satisfy the same state adopted version of the International Building Code (IBC) as a site built structure. Modular Building Institute The IBC sets structural, fire resistance, egress, and accessibility requirements. IBC Effective Use
The first practical hurdle is occupancy classification. The IBC Section 202 defines a data center but does not assign it to a specific occupancy group. The local authority having jurisdiction, called the AHJ, must decide the correct group based on use, hazards, and risk. The most common classifications are Group B (Business), Group F-1 (Moderate Hazard Factory Industrial), or Group S-1 (Moderate Hazard Storage). ICC Each group triggers different fire protection, egress, and ventilation requirements, and a misclassification early in design can force expensive rework later.
A pending IBC proposal, known as G38-25, would explicitly assign AI data centers to Group F-1, removing the current ambiguity. The proposal is working through the 2025 code cycle and awaits action at the Public Comment Hearings. ICC Separately, the ICC has a dedicated Guideline Committee, G12, developing a Data Center Guideline to clarify compliance pathways and identify gaps across occupancy classification, fire protection, structural design, electrical systems, and environmental impacts. ICC G12, BSJ article
Because states adopt IBC editions on their own schedules, some states are 6 to 9 years behind the latest edition. Modular Building Institute A developer must verify which edition the local jurisdiction has adopted.
The National Electrical Code (NFPA 70) Article 646 covers modular data centers directly, setting requirements for electrical equipment, wiring, labeling, and installation within a modular unit. NFPA 70, Article 646 The NEC is adopted by all states, though the edition in effect varies.
What product safety standard applies to factory built modules?
Even before a module reaches the site and becomes subject to the building code, it is a manufactured product. The applicable product safety certification is UL 2755:2025, the Outline of Investigation for Prefabricated Modular Data Center Systems and Related Modular Units. Modular compliance analysis, Intertek, UL Solutions insight, Intertek analysis UL 2755 provides a safety framework covering module type categorization, a comprehensive code compliance framework, and enhanced construction requirements for prefabricated units.
A critical distinction under UL 2755 and local code enforcement is whether the unit is treated as equipment or as a building. A prefabricated unit that has only exterior service access, where a technician reaches in through a panel and never enters the interior, may be classified by the AHJ as an equipment enclosure. If the design includes a side hinged man door, a walkable interior space, or required human entry for service, the AHJ may consider the unit a building, which can bring in state modular building requirements. Intertek
This choice matters because a building classification pulls the unit into the full plan review, in plant inspection, and state insignia requirements of the state’s modular program. An equipment classification keeps it under the product safety certification alone, though the unit must still interface with site built infrastructure that meets the IBC.
How do state modular programs work?
About 39 states operate their own modular building programs. Stream Modular, Offsite Builder These programs do not create a separate building code. Instead, they provide a regulatory pathway for factory built buildings. A state authorized third party inspection agency, called a TPIA, inspects the factory production against the approved plans that were reviewed and stamped by the state program. When a module arrives on site, it carries the state’s insignia, which satisfies the factory inspection requirement. The local AHJ remains responsible for site work, the foundation, utility connections, and the final integration of the modules.
The national standards that guide these state programs are the ICC/MBI Standards 1200 (planning, design, fabrication and assembly) and 1205 (inspection and regulatory compliance). They are ANSI accredited standards for modular construction review and approval. Virginia (effective January 18, 2024), Utah (SB 168, 2024), Montana (September 2024), Rhode Island, and Colorado (effective January 1, 2025) have adopted ICC/MBI Standards 1200 and 1205. Modular Building Institute, Modular Building Institute, Modular Building Institute, ICC, ASPE Pipeline
Texas runs its industrialized building program through the Texas Department of Licensing and Regulation (TDLR), under standards set by the Texas Industrialized Building Code Council. It covers plan reviews, in plant inspections, and site inspections. Stream Modular Florida’s program is overseen by the Department of Business and Professional Regulation (DBPR) and emphasizes hurricane resistance and wind load requirements, which matter for a state where AI data center construction is growing. Stream Modular
A modular AI data center moving through a state program typically follows this sequence. Step one, the design is submitted to the state program for plan approval. Step two, the approved plans are sent to the factory, and a TPIA is assigned to inspect during construction. Step three, the factory builds the modules while the TPIA conducts inspections. Step four, the finished modules are affixed with the state insignia and shipped. Step five, on site, the local AHJ inspects the foundation, the module to module connections, the utility tie ins, and any site built ancillary structures.
What transportation and logistics rules apply?
A module is a heavy, wide, long load that must travel public roads. The federal baseline for size and weight on the Interstate System comes from 23 CFR Part 658. 23 CFR Part 658 Any module that exceeds 8 feet 6 inches in width, 13 feet 6 inches in height, or 53 feet in length triggers the need for state oversize and overweight permits. Trucks hauling modular units can be over 20 feet wide and 120 feet long. FWF Logistics, Bear Down Logistics
State oversize permit rules are specific to each state and can take anywhere from one day to over two months to obtain, depending on the size and location of the buildings. FWF Logistics Many states restrict movement to daylight hours and restrict travel on holidays. Oversize.io
Georgia offers an example of precise state requirements. Under Chapter 672-2, a modular unit is defined as a building transportable in sections with a box width of 8 feet or more and a box length of 40 feet or more, with all sections no more than 16 feet wide. Overall length cannot exceed 80 feet including the hitch. A modular unit transporter must use 12 inch I-beams that are doubled and fabricated together, and have brakes on all axles. Georgia Rules and Regulations, Rule 672-2-.01(h)
A developer must also prepare the delivery route. Access roads need to support 40 ton modules with turning radii of 75 feet and a surface reinforced for 100,000 pound vehicles. Introl, Dec. 2025 update Upgrading the road can add significant cost. A QTS modular deployment in Phoenix, Arizona required upgrading 2.3 miles of access roads, at a cost of $1.2 million. Introl, Dec. 2025 update
What OSHA rules apply during factory fabrication versus on site erection?
The Occupational Safety and Health Administration (OSHA) has two separate sets of standards that matter for modular construction. Which one applies depends on where the work is happening.
Inside the factory, where modules are fabricated, OSHA’s general industry standards under 29 CFR Part 1910 govern. OSHA 1910 For example, fall protection is triggered when a worker is 4 feet above a lower level under 1910.28. OSHA 1910.28, OSHA 1926.501, OSHA 1926.501
Once the module is on site and the work involves erection, crane lifts, and assembly, OSHA’s construction standards under 29 CFR Part 1926 apply. OSHA 1926 On a construction site, the fall protection trigger rises to 6 feet under 1926.501. OSHA 1910.28, OSHA 1926.501 Crane operations on site are also governed by 1926, and module placement is typically halted when wind speeds exceed 25 miles per hour. Introl, Dec. 2025 update
One of the most cited OSHA violations for 15 consecutive years is fall protection under 29 CFR 1926.501, with 5,914 violations issued in fiscal year 2025 alone. National Safety Council A developer running a modular project must have a safety plan that recognizes the split. Factory workers operate under one set of rules. The crew setting modules on site operates under another.
Also, 27 states operate their own OSHA approved state plans with requirements that can go beyond the federal minimums. OSHA State Plans For instance, a project in a state like Virginia, which has its own plan, may need to meet additional state specific worker safety rules during the on site phase.
How does federal permitting policy affect modular AI data center projects?
Executive Order 14318, signed on July 23, 2025, directs federal agencies to accelerate permits for qualifying data center projects. It defines a Data Center Project as a facility requiring more than 100 megawatts of new load dedicated to AI inference, training, simulation, or synthetic data generation. Exec. Order No. 14318 The order authorizes the Federal Permitting Improvement Steering Council Executive Director to designate qualifying projects as transparency projects under the FAST-41 statute, and authorizes the Executive Director to publish them on the Permitting Dashboard within 30 days of agency notification, including schedules for expedited review. Exec. Order No. 14318
For modular projects, this matters because the off site fabrication can run in parallel with the federal permitting sprint, potentially compressing the overall schedule even more. The order does not create a new building code path. It focuses on accelerating federal permitting of AI data center infrastructure and associated energy infrastructure, including generation equipment, transmission lines, and pipelines. CRS Report R48762
The earlier Executive Order 14141 from January 2025 directed DoD and DOE to identify federal sites for frontier AI data centers, but it was revoked by EO 14318. Exec. Order No. 14141, Exec. Order No. 14318
How does modular compare to traditional construction on project delivery?
The following table compares a typical modular AI data center project with a traditional stick built equivalent.
| Factor | Traditional construction | Modular construction |
|---|---|---|
| Typical timeline from contract to operation | 24 to 36 months | 8 to 13 months |
| Capital cost for a 4 MW facility | Approximately $32 million | Approximately $40 million |
| Construction labor cost savings | Baseline | 60% less, saving $2 to $3 million on 4 MW |
| On site foundation preparation | 16 weeks typical | 8 weeks with standardized post tensioned slab |
| Quality (first pass yield) | 60 to 70% | Approximately 95% |
| First year operational availability | Requires 18 to 24 months tuning | 99.982% |
| Time to revenue | Baseline | 12 to 18 months earlier revenue |
| Grid connection planning | 4 years average wait, up to 7 | Same, but factory work runs in parallel |
[Sources, Introl, Dec. 2025 update, Data Center Knowledge via ConstructLaw]
These numbers come from actual projects. Compass Datacenters standardized a modular foundation design across 25 deployments using post tensioned concrete slabs, cutting foundation preparation from 16 weeks to 8 weeks while maintaining structural integrity for Category 5 hurricane zones. Introl, Dec. 2025 update Aligned Data Centers placed modules for a 3 megawatt facility in 5 days using two 500 ton cranes working in coordination. Introl, Dec. 2025 update
Grid interconnection remains a bottleneck regardless of construction method. The average grid connection wait time is 4 years in the US, with reports of up to 7 years. Data Center Knowledge via ConstructLaw A modular project cannot bypass that wait, but it can compress the on site build to a window that fits once the interconnection agreement is in hand.
The market is voting strongly for modular. In a 2022 survey by Vertiv and Omdia, 93 percent of AI data center operators said prefabricated modular solutions would be their default construction strategy in the future. Vertiv Vertiv itself has shipped over 1,500 modular data centers to more than 800 sites worldwide, delivering over 250 megawatts of IT load. Vertiv
Key takeaways
- Modular AI data centers must meet the same IBC requirements as site built ones. There is no separate modular building code. Modular Building Institute
- Classify the occupancy correctly early. Group B, F-1, or S-1 changes fire and egress requirements. The pending IBC proposal G38-25 may settle this by assigning data centers to Group F-1. ICC
- Factory built modules need UL 2755:2025 certification. Design decisions, such as whether the module has a walkable interior, determine if the unit is treated as equipment or a building. Building a unit off-site as a modular structure pulls it into the state modular program where one exists. ICC NTA
- About 39 states run modular programs that rely on third party inspection agencies. The factory work gets inspected and approved before delivery under the state program, as indicated by the state insignia affixed to each module, leaving foundation, utility connections, and on-site assembly for the local authority. Offsite Builder
- Transporting a module wider than 8 ft 6 in, taller than 13 ft 6 in, or longer than 53 ft requires state oversize permits. Permit timelines range from one day to over two months and often restrict travel to daylight weekdays. FWF Logistics
- OSHA’s general industry standards apply in the factory. Construction standards apply on site. Acknowledge the split in the project safety plan, especially the different fall protection triggers at 4 feet and 6 feet. OSHA 1910.28
- Modular capital cost is 20 to 30 percent higher per megawatt upfront. The speed to revenue, labor savings, and quality consistency often close the gap. Introl, Dec. 2025 update
- Federal permitting acceleration under EO 14318 applies to projects over 100 MW dedicated to AI. EO 14318 accelerates the federal permitting review window for qualifying AI data center projects through NEPA categorical exclusions, FAST-41 coordination, and streamlined environmental reviews. Exec. Order No. 14318
Frequently asked questions
Q:What is the difference between modular and prefabricated construction?
A:The terms are often used together. Prefabrication means any building component made off site. Modular construction means entire sections that form a finished space are assembled in a factory and transported to the site as a complete unit. A modular AI data center delivers an IT hall, a power room, or a cooling plant as a fully integrated factory built block.
Q:Do modular AI data centers need their own building permit?
A:Yes, but the permitting path is split. The module itself is reviewed and approved through the state modular program, if one exists. The local building department permits and inspects the foundation, the utility connections, and the assembly of the modules on site. The factory built portion arrives with a state insignia that satisfies the factory inspection requirement.
Q:Is a UL 2755 certification enough by itself to get a building permit?
A:No. UL 2755 is a product safety certification. It does not replace the IBC or local building code requirements. The local AHJ will still require compliance with the adopted building code. If the unit is classified as equipment, UL 2755 may be the primary safety standard accepted. If it is classified as a building, the state modular program requirements also apply.
Q:How long does it take to transport a module and what can go wrong?
A:Transport permit approval takes between one day and two months, depending on the state and the route. Most moves are restricted to daylight hours on weekdays. Common problems include road upgrades needed for turning radius and weight support, bridge clearances, and weather halts. Crane lifts on site stop when wind speeds exceed 25 miles per hour.
Q:Why is modular more expensive per megawatt upfront?
A:The main cost driver is the factory labor, engineering, and the integrated systems that are built and tested under controlled conditions. Materials like steel and specialized cooling equipment are the same. A 4 MW modular facility costs about $40 million compared with $32 million for a traditional build, but the 60 percent labor reduction and 12 to 18 months of earlier revenue offset much of that premium.
Q:Does a modular AI data center help with the grid interconnection timeline?
A:Not directly. Grid interconnection is a separate process governed by the utility and the regional transmission organization. The wait averages 4 years and can reach 7 years. What modular construction does is shorten the on site build to 8 to 13 months, so once the interconnection agreement is in place, the project can be completed and online faster.
Q:Are there tax or depreciation differences for modular versus traditional construction?
A:For federal income tax, what matters is what the property is, not whether it was built in a factory or on site. A modular AI data center that is permanently affixed to the land is generally treated as real property and depreciated over 39 years as nonresidential real property, the same as a traditional build. A cost segregation study can still reclassify much of the electrical, cooling, and other equipment to shorter 5 or 7 year recovery periods in either case. The modular method itself does not change the tax answer. For the depreciation rules in depth, see the tax articles in this series.
Q:What happens if a state has not adopted ICC/MBI Standards 1200 and 1205?
A:The state program still operates under its own rules, which generally require compliance with the adopted IBC edition. The ICC/MBI standards provide a common framework, but their absence does not prevent modular construction. However, the developer faces more variability in plan review and inspection processes from state to state.
Q:Can a module be modified after it is placed on site?
A:Yes, but modifications that affect structural integrity, fire resistance, or egress require a new review. The local AHJ has jurisdiction over site modifications. If a module was approved under a state modular program, substantial changes may need to be reviewed by the state program as well.
Q:How does the equipment versus building classification play out on a project?
A:If the module has only exterior access panels and a technician never steps inside, the AHJ may agree it is equipment. That can simplify approvals. But most high density AI modules need interior access for server swaps, liquid cooling maintenance, and cable management, so they are almost always classified as buildings, triggering the full state modular program.
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Junde Liu, JD, LL.M. (Taxation) candidate at UF Law. Originally published on Compute Law Blog. This article is general information and does not constitute legal advice. Reading it does not create an attorney client relationship. The reader should not act on the basis of any content here without first consulting a licensed attorney in the relevant state. Last reviewed for accuracy May 23, 2026.