Electrical Prefabrication Rising in the Data Center Market
Containerized electrical equipment is an integrated, prefabricated enclosure containing electrical infrastructure. These exterior pre-engineered containers include electrical distribution equipment, lighting and associated lighting controls, receptacle power, self-contained mechanical systems, and fire suppression systems (if required).
Once reserved for remote, off-grid, industrial applications or temporary power, this prefabricated option has gained popularity in the data center market with three major benefits:
1. Reduce Building Footprint
By relocating majority of the electrical infrastructure from inside the building to exterior containers, the need for large interior electrical rooms and associated square footage can be eliminated. Clients can repurpose these spaces for rentable data hall usage or reduce the overall building footprint. Either option increases the rental to overall building square footage ratio. Current applications have increased rentable data hall square footage from 35% to over 50% of the building’s total interior footprint.
2. Standardize Deployment
Construction phasing is a critical component on data center projects. Containerized electrical equipment is easily standardized and duplicated for staged deployment. Data centers typically require a portion of the electrical capacity available for an initial phase with the remaining electrical capacity available shortly afterwards. Designing the electrical infrastructure into deployable segments allows each segment to be standardized for an economical release for initial and further phases. This can be implemented for a building-wide, campus-wide, and even owner-wide applications.
3. Prefabricated Approach
The general prefabrication benefits are applicable for containerized electrical equipment. These advantages include safety, quality control, and production value. For many projects, removing most of the electrical equipment fabrication off-site in a controlled, conditioned, and safe environment is highly desired.
To fully capitalize on the benefits of containerized electrical equipment, careful planning considerations need to be implemented:
With the containerization approach, most of the electrical infrastructure is designed, coordinated, and finalized early in the design process. The building’s layout and site orientation are dictated on where and how the containerized electrical equipment connects to the interior electrical distribution system and is distributed throughout the spaces. With moving the electrical infrastructure to the exterior equipment yard, civil and structural components like stormwater drainage and structural footings are coordinated with proposed electrical equipment and associated feeder locations. Additional complexity arises if the building structure is precast since precast openings can influence the location and elevation of exterior containers. These openings are coordinated to avoid precast seams and columns; therefore, can dictate the container’s spacing and width. Architectural, civil, structural, and other trades need to agree on overall design building penetrations, slab heights, and elements, including proposed piping/conduit routing elevations.
Service and Feeder Connections:
A key planning consideration is determining how services and feeders will enter and exit the containerized electrical equipment. These items include electrical feeders, branch circuiting, grounding, low voltage systems pathways, and (if required) fire suppression piping. Unplanned raceways after the containerized electrical equipment arrives onsite can result in higher cost and schedule delays.
Coordination is required for floor openings within the electrical container for underground services and feeders. Overhead options include conduit, cable bus, and bus duct. Each option requires penetration coordination with the container manufacturer. Reviewing support locations of overhead feeders with the owner’s operations team is essential to avoid road blocks in future maintenance and construction phasing.
Scope of Work Division:
Many owners elect to procure the containerized electrical equipment. A defined scope of work at the beginning of the project between the container manufacturer, equipment vendors, electrical and controls contractors, and commissioning agent will helps avoid any scope gaps. Common containerized equipment scope gaps are related to equipment accessory procurement and installation, interconnecting wiring, and pre-functional testing. It’s advantageous to incorporate a majority of the scope with the container manufacturer; however, shipping restrictions, lead times, and required field coordination should be evaluated prior to their scope definition. For example, container penetrations should be limited to major openings that can be stabilized for shipping. The motion and circumstances of shipping stipulate it is best to field mount trapeze supported conduit and exterior mounted elements like light fixtures and security devices. Designate sub-floor space and overhead “zones” for feeders. The container manufacturer can provide permanent supports coordinated with the field installed feeders.
The Design-Build Delivery Method provides advantages to implement these planning considerations. This method promotes early coordination between designers and installers which is unavailable in the traditional Design-Bid Delivery Method. This partnership of the project team directly impacts the benefits of the containerized approach.