Going prefab — data centres on the move

As converged infrastructure gains momentum in Australia, so too will prefab data centres.

Converged infrastructure (CI) is reshaping the Australian IT market, with speed and efficiency being the keys, as CI has brought the ability to provision, test and deploy IT much faster than ever before. The trend is being adopted at an ever-increasing pace and is pushing the industry further down the path of standardisation, modularity and prefabricated (prefab) construction. One example of this is the growing uptake of prefabricated data centres.

When CI is applied to the data centre, the vendor provides preconfigured bundles of hardware and software in a single framework. Fundamentally, it is a collocation of computer, storage and network resources that is managed as a single IT asset, often in one or a small handful of cabinets. This system is then dropped into a data centre. Whether it is a simple reference design or pre-constructed by one of several turnkey vendors, these converged stacks are typically characterised by a high degree of virtualisation and automated software management.

While the benefits of prefabricated data centres are well understood, many of the practical considerations are not, especially when compared to regular ‘stick-built’ data centres. In order to ensure companies are embracing the technology correctly, a thorough knowledge of prefab implementation is important, because the planning, design, site preparation, procurement and installation stages all play vital roles in the process.

Planning and design considerations

Besides shorter process times, there are two planning considerations that are unique to prefabricated data centres: how the equipment is classified financially and the degree of component-level design engineering involved.

Prefabricated modules that are assembled in a factory and packaged either as an assembly on a skid or as an assembly within an enclosure possess the attribute of being considered a ‘product’ rather than a basket of parts or subsystems. This provides a company with certain financial options that are generally not afforded to stick-built date centres. For example, they may be booked and depreciated separate to the building, they may be leased (or sold and leased back) independent of the rest of the assets on the site, and may be moved (or relocated) from one regional data centre to another with prior depreciation recognised and remaining value intact.

Engineering a data centre built from prefabricated modules also involves more system-level design work when compared to engineering one built from products and parts. Prefabrication carries an implicit expectation that the components within the modules are well matched and thoroughly integrated. Communications and controls are ready to function when the module is delivered, with minimal on-site work. Prefab data centre design can be half of traditional models, typically reducing from 24 weeks to 16 weeks.

Site preparation

Whether the project is a retrofit data centre or a new ‘greenfield’ location, some degree of work is generally needed to ready the site. For prefab data centres there are some unique considerations needed for obtaining permits and foundation for modules.

The permitting process for data centres assembled from prefabricated modules generally resembles that of conventional builds, but one point of difference is that the construction drawings can be simpler, as all the detailed information is available from the manufacturer. Another factor is that prefabricated data centres have been pre-tested and pre-approved. As the ‘inspection function’ has been performed by recognised agencies and the cost of those approvals is incorporated into the purchase price, local inspectors are not tasked or responsible for module inspection.

Many modules are designed to be weather-tight enclosures, making them well suited for outdoor installation as standalone structures. Whether indoor or outdoor, common types of structure foundations used are continuous concrete slabs, multiple concrete slabs, piers or a combination of these. The style and type of foundation selected has much to do with the physical properties of the site, such as soil conditions, surface water drainage, the presence of frost, as well as seismic and wind loading requirements for a particular geographic location.

Procurement considerations

Since prefab data centres are designed with mobility in mind, traditional transport and packaging considerations are always taken into account.

As transportation of data centre modules to a site is generally by truck, standards imposed on truck and cargo weights and dimensions are taken into account well in advance. Despite variations between Australian states, modules are usually designed to suit all conditions. Since data centre modules are often at the upper end of the size and weight limits, manufacturers often use the services of transportation and logistics companies that specialise in the delivery of large, singular payloads.

Another point of difference between prefab and traditional data centres is the packaging. Traditional projects use significant volumes of palettes, cardboard and plastic. On the other hand, prefabricated modules have the majority of the physical infrastructure (power, cooling, rack) subsystems installed and secured within the modules prior to delivery, which reduces, by an order of magnitude, the amount of packaging necessary to transport the modules safely.

Site considerations

Well-designed prefabricated modules facilitate a simpler, quicker installation process. To ensure reliable, efficient operations, a key factor that should be considered during the installation process is where to position and secure the module.

For ideal operations, modules should be placed so their shortest side faces the sun, minimising heat gain. They should be placed away from trees, lamps, wires or other objects that could pose a hazard during a natural event. The site layout should discourage potential vehicular collisions. Beyond this, modules should be free from obstruction and located in an area that allows proper water drainage. In some cases, they can be stacked to save space.

Implementation and deployment of prefabricated data centre modules is substantially different to that of a traditional data centre build. As converged infrastructure continues to gain momentum in Australia, so too will prefab technology. As these trends become more common, it is important for companies to understand all considerations to implement them effectively.