Technical Article


Prefabricated Modular and Containerized Data Centers: Pros and Cons


In the last few years and more and more frequently, the term “prefabricated modular and containerized data center” has become more common in data center projects being executed and in short- and medium-term project plans. Nevertheless, the term continues to be used indiscriminately without really understanding the differences between one and the other and without really understanding their advantages and disadvantages and, in turn for traditional (brick and mortar) construction projects. This is precisely the subject that this article deals with.

First of all, a prefabricated modular data center is not the same as a containerized data center and, on the contrary there are clear, marked differences between them.

A containerized data center, as its name suggests, is a packaged data center solution that has been pre-engineered at the factory. It has been put together in an ISO container (20 feet by 8 feet or 40 feet by 8 feet) for shipping by sea. It has been reinforced structurally to support the weight of the equipment inside. It may have additional customized features such as armor plating on the structure or have specific access routes to the racks (and other parts). Typically, it is used in locations that are difficult to reach (e.g., in a jungle area) or as a temporary or contingency solution or a solution that needs to be implemented quickly and be mobile.

Due to its limited area based on standard ISO dimensions, it also has a limited capacity for the number of racks and the total power in the IT loads. These loads are around 150 kW for “all in one” solutions (that integrate the IT racks with power and cooling equipment in a single container). These loads may also be around 250 kW for containers dedicated to IT cabinets that need additional containers with power and cooling equipment.

For its part, a prefabricated modular data center is a customized solution for the precise quantity of IT cabinets and for the power and cooling capacity making up the data center. These may be based on components of modular blocks, pre-assembled and factory tested and provide a scalable solution and a delivery time that is shorter than in traditional brick and mortar construction. Its major difference in relation to a containerized solution is that there is not a limited capacity for the number of racks or the total power for the IT load, but they may be assembled and dispatched in modules that have the right dimensions to ease shipping and transportation.

The three most common types found on the market are:

d) Micro data center: a complete pre-fabricated solution in a single piece called “all in one.” In general, the maximum IT load is 150 kW in an ISO container. This type of data center is useful when no more growth is expected since, for a quantity larger than 2 or 3 modules, it may be more costly that a traditional construction solution. Normally, they are used as temporary (event-based) solutions, for remote locations, in very aggressive outside environments (petroleum or industrial applications) that require mobility or as a small data center for disaster recovery.
e) Semi-prefabricated: when there is traditional construction with IT space to grow, but the electrical capacity or the remaining sufficient cooling is not available, or vice versa. They are also usually used as a temporary or short-term solution to take care of specific demand while a long-term plan is defined with a final solution.
f) Fully prefabricated: a full solution in blocks of modules that may be used as a “Disaster Recovery” or contingency site or when the data center is expected to repeatedly grow “homogeneously” in stages of phases.

In addition, some prefabricated solutions dedicated to power modules (Switchgear, Transformador, UPS, electrical panels) to deal with specific electrical capacity demands are shipped on metal pallets, open frames or on rails for ease of transport to be used inside locations.

The main factor that is boosting the use of prefabricated modular solutions is the implementation times. The reason is that standard components are used that have been preassembled and tested at the factory and delivered and placed into commission on site. They provide reliable, efficient solutions with a very good “time to market” and the modular blocks may offer greater scalability, ease of replacement or field upgrades.

Both containerized and prefabricated modular solutions may offer the following advantages in relation to implementing a data center in traditional brick and mortar buildings. However, what is expressed below may not always be taken for granted so, they need to be validated case by case:

f) Shorter implementation time or “time to market” due to less civil work to implement and a possibly shorter time for obtaining construction permits. The civil work is mostly related to site preparation and the slab where the prefabricated structure will rest. It also includes laying pipes and digging drains, building security grids or walls, setting up an area for fuel tanks and areas for masonry work for bathrooms, an electrical sub-station and offices. Even so, depending on the manufacturer, these areas may be included as part of the modular solution. In addition, manufacturing, preassembling, and testing the solution at the factory may be done simultaneously with the civil outfitting. Market supply indicates full data center implementation times of between 5 and 6 months.
A check needs to be run to be sure that shorter design and planning times do not come from using existing reference designs since they do not necessarily match all the client’s project requirements.
g) Lower capital expenses facilitate greater scalability or growth in phases with solutions that may store greater density in more optimized spaces with a capacity that more closely matches the project phases without any excessive dimensioning that causes early or higher costs. In addition, more optimized spaces may lead to greater energy efficiency since they move the thermal loads closer to the cooling units.
h) More predictable subsequent operating phases allow for a module-based procurement expansion plan with fixed pricing, in addition to lower depreciation costs per module that result from life cycles similar to the IT servers or with a maximum life cycle of 10 years (instead of 15 or 20 years).
i) Different block availability and project stage or phase requirements are easier to come by since each block may be constructed specifically with a separate infrastructure.
j) The inspection process is easier so the commissioning time may be shortened since an assumption is made that the pipes and internal electrical wiring to and from the physical infrastructure equipment has been tested during preassembly and manufacturing. This cuts back on the field work for the modules’ electrical, mechanical, and external telecommunications connections. Of course, this issue goes hand in hand with the advantage indicated first.

It bears clarifying that data center projects with traditional construction may also include phase-based scalability and expansion. However, their planning needs to be done more years in advance than for prefabricated solutions. This may result in some invalid assumptions some years later due to rapid changes in technology, innovations, better supplies, or new competitors on the market. Nevertheless, even in prefabricated set-ups, expandability and growth depend mostly on an indication of maximum future capacity, which is no different in a traditional set-up.

On the other hand, for data centers that provide placement services to third parties, traditional construction is much more practical and flexible because it is able to handle such varied needs for client spaces. It also makes it possible for the “cages” (and even thermal containment areas) to be easily installed and reconfigured to adapt to change and required growth. Moreover, growth using more discrete units (a rack) may be achieved more easily while prefabricated modular and containerized solutions grow using blocks or larger units. They need to have ample spaces for adding one or more cabinets and possibly even heavy machinery or tools.

With the understanding that it may be a paradigm, the generalized perception that exists on the market may not be cast aside either. The perception is held by clients who pay for outsourced services that their IT equipment or services (placement / hosting / managed services) are more secure if they are inside a traditional building than if they are in a container or in a prefabricated modular solution.

There is also a need to consider that almost all the prefabricated solutions on the market have to have some traditional construction to be used as a recognized physical address for the business. Depending on the project, areas may need to be included such as an electrical (medium tension) sub-station, bathrooms, security room, storage area, and even offices.

Finally, it is a good idea to take into account the fact that security should not be a decisive factor in traditional construction and prefabricated solutions since it depends on the client’s needs, the client’s business, and the organization’s internal policies and not on whether the data center is a prefabricated or traditional solution. In both cases, the security level required by the client may be implemented.

In addition, the main differences between containerized and prefabricated modular solutions are:

g) Greater flexibility in prefabricated solutions for the number of cabinets, size and power density and for future growth, adjustments or field modifications.
h) Containerized applications are mostly oriented toward being a temporary, transportable or emergency solution or for use at remote sites. Meanwhile, prefabricated solutions are used more as a permanent solution, as a complement to additional capacity for an existing facility and as disaster recover or as an alternate contingency site.
i) The esthetic appearance is much more pleasing and customizable in prefabricated solutions, making them more appropriate for enterprise data centers since, once they are assembled on site (and even painted), they may look similar to a traditional data center. On the contrary, containerized solutions without any esthetic adjustments may give off an air of “job site” to the location, making them unattractive for enterprise data centers or for providing services to third parties.
j) Since prefabricated solutions may be built without space limitations compared to containerized solutions, they provide more ease in maintaining and respecting service spaces based on local sets of norms. Containerized service is usually provided using exterior panels for doors that affect how air tight the air conditioning systems are.
k) Unlike a container, special attention should be paid to which prefabricated solution should be chosen. It may be hauled disassembled in standard sizes similar to an ISO container. Otherwise, hauling on highways may require special equipment and permits that are not just very difficult to obtain in the countries in the region, but are also very costly.
l) Normally, containerized solutions are a single height since it is common for the roof to bear condensers for the air conditioning system. On the contrary, some prefabricated solutions may have two and up to three levels or floors to capitalize better on the footprint.

It is pertinent to consider the differences and advantages that a prefabricated modular solution may have over a containerized solution. Although both types of solutions have more favorable scenarios for each of them, in practice, all scenarios need to have some traditional construction that complements the areas that a complete data center project requires.

Therefore, the specific business needs should be analyzed as they relate to the project’s and the client’s needs based on the possible traditional construction scenarios and containerized or prefabricated modular solutions, including their pros and cons, to decide which better matches and most appropriately satisfies the requirements and needs. Each data center project is unique so there is no applicable rule when choosing the possible implementation scenario.

By: Juan Carlos Londoño Z. – Senior Consultant Engineer – INGENIUM
[email protected]