Modular and Prefabricated Data Centers: Speed, Footprint and Permitting

The terms cover a spectrum rather than one product. At one end, individual systems are built and tested in a factory: power skids, switchgear line-ups, prefabricated electrical rooms (often called eHouses or power modules) and packaged chiller plants. In the middle are modular white-space products that combine racks, power distribution and cooling in units set inside a shell. At the far end are containerized or volumetric data centers, where the IT space itself arrives on a truck. Most large campuses mix these: a conventional building surrounded by factory-built power and cooling.

The scale of a single module has grown. Vertiv’s OneCore, announced for global availability in August 2025, packages power, thermal and IT infrastructure in blocks of 5 to 50 MW configurable for 96 to 944 racks, inside a Vertiv-supplied steel shell, and Vertiv says parallel manufacturing of the electrical and mechanical modules shortens timelines.¹⁰ JLL describes a shift from build-to-suit development to “assemble-at-scale” and expects designs to grow into mega-modules of 10 MW or more.³ At the small end, containerized units remain common for edge data centers.

The main driver is schedule risk. Trade coverage of JLL’s 2026 outlook reported that more than half of 2025 data center projects ran at least three months late.¹¹ Moving work into factories lets fabrication run in parallel with site work and replaces some field labor with controlled assembly.¹² Operators using factory-built power skids, prefabricated cooling modules and pre-assembled electrical rooms report 12–18 months from site clearance to energization.¹

Adoption is broad but the best survey data is sponsored. In a 2022 Omdia survey sponsored by Vertiv, roughly half of 228 companies that operate their own data centers had deployed some form of prefabricated modular solution, and 93% said prefabricated modular solutions would become their default construction strategy.¹³

Factory output is now committed years ahead. Schneider Electric and Compass Datacenters announced a five-year, $3 billion agreement in 2023 to jointly manufacture prefabricated modular data centers; Schneider had already delivered about 150 modular solutions to Compass from its West Chester, Ohio operation, and the companies run a 110,000-square-foot facility in Red Oak, Texas.⁴ In 2026 Schneider wrote that buyers increasingly sign multi-year agreements, giving the example of 10 modules a month for three years, cited prefab deals with Switch and Digital Realty, and said it planned to double its prefab team to more than 2,000 employees.⁵ Factory slots behave like any other long-lead item; see data center equipment supply chain constraints.

The most extreme example is temporary. In July 2025, reporting relayed from SemiAnalysis said Meta was erecting tent structures with prefabricated power and cooling modules to add AI capacity while permanent buildings were under construction, trading redundancy for speed.¹⁴ Few owners would accept that trade, but it shows how far speed has moved up the priority list.

Published time savings cluster around a third or more. Flex estimates that factory integration and parallel workflows can shorten schedules by 30% or more, against traditional end-to-end delivery of about 24–36 months.¹² Trade analysis cites 30–50% reductions for highly modularized projects, and modular builders claim 10–15% lower installed cost.¹¹¹ Nearly all of these numbers come from companies that sell modules, so treat them as upper bounds and ask for reference projects with dates from notice to proceed through commissioning.

The savings sit inside the building scope. Prefabrication does nothing for a utility’s load study, a transmission upgrade or a new substation, and a module that arrives before service is ready has nowhere to plug in. On many sites the power path is the longest track, which is why power timelines and a phased build-out matter more than the construction method. Our guide to how long it takes to build a data center covers the full sequence.

Prefabrication moves space out of the building and into the yard. Power modules, packaged chillers and generators usually sit on outdoor pads, so the equipment yard, its clearances and its orientation toward neighbors carry more weight in the layout. See cooling plant and equipment yard space and noise setbacks and buffers. Pads and paved access add impervious area, which feeds into stormwater management.

Construction logistics also need land. Modules arrive in sequence and may be staged before setting, so a site needs laydown area, crane pads, turning room for long trailers and roads built for heavy loads. Foundations are designed around module weights and soils, which makes an early geotechnical investigation more important, not less; see slope, soils and geotechnical review.

Density changes the ratio of building to plant. UL says its revised standard addresses AI workloads of 200 kW or more per rack.⁷ Higher rack density shrinks the data hall for a given load, but not the transformers, switchgear and heat rejection behind it, so total acreage is still driven by power, cooling and setbacks. Our guide to building footprint and lot coverage covers the zoning math.

Module size is limited by the road. Federal rules set a 102-inch width limit for commercial vehicles, and FHWA guidance says a vehicle whose cargo extends past 102 inches needs an overwidth permit on the National Network and its access routes.⁶ Permits come from each state on the route and typically specify the route and travel times. Many power and cooling modules exceed that width, so they move as oversize loads.

The last miles are where sites fail. A parcel can sit near an interstate and still be hard to reach if county roads are narrow, bridges carry low weight ratings, rail crossings are tight or overhead lines cross the route. Height limits are set state by state, so a route survey belongs in early diligence for any modular plan. Our guide to heavy-haul routes and construction access explains what a route study checks, and the same route usually serves the large transformers a campus needs.

Prefabrication splits approvals into two tracks. On the electrical side, UL explains that NEC Article 646 lets manufacturers meet the requirements for prefabricated data centers with a single certification, UL 2755, if it is obtained before the module ships from the factory.⁷ UL says the 2025 edition adds newer NEC requirements, high-density power and cooling, and interoperability requirements for modules from different manufacturers.⁷

A listing is not a building approval. Intertek notes that UL 2755 does not replace the International Building Code or state and local review, and that the authority having jurisdiction decides whether a unit is equipment or a building; features such as side-hinged man doors or walkable interior space can change that call.² The classification matters because a building triggers occupancy, egress and fire protection rules; see building and fire codes for data centers.

For factory-built building modules, the ICC/MBI 1200 and 1205 standards (2021) cover planning, design, fabrication, transport and assembly, and the inspection and approval process, including state modular programs, third-party inspectors and the local authority.¹⁵ State programs illustrate the split. Maryland sets construction standards for modular buildings and preempts local ones, but the owner still applies to the local building department, which issues the permit after state approval and inspects the foundation and all site work.⁸ Texas uses third-party in-plant inspections, while the local building official handles site inspections and may require plans before a permit.⁹

Zoning does not change. Use permission, height, setbacks, noise limits, stormwater and generator air permits all still apply; see zoning for data centers and the data center permitting process. Temporary structures such as tents may fall under separate rules, so confirm with the county early.

A modular plan pays off only if the site can feed it power on time and receive the modules. A practical screen:

1. 01Confirm the power date first. If the utility path takes longer than the factory, prefabrication will not move the finish date.
2. 02Survey the delivery route from the nearest interstate for width, height, bridge and turning limits, and ask which state permits apply.⁶
3. 03Lay out the equipment yard, crane pads and laydown area early, and check them against setbacks, lot coverage and stormwater limits.
4. 04Commission geotechnical work sized to module and crane loads.
5. 05Ask the county or city whether the modules will be treated as equipment or buildings, and which agency inspects what.²⁸
6. 06Confirm the manufacturer’s factory slot and listings, such as UL 2755, in writing.⁷⁵

If you are weighing a parcel for a fast, factory-built deployment, we can get a site reviewed for power timing, access and layout before you commit to a module order.