DCD Construction Supplement 2022 by DCD Magazine

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Contents 4. Building underwater Subsea data centers could be more efficient. But how do you build them? 8. Advertorial Building the largest data centers 10. Do we need architecture? Data centers have a job to do. Why do they have to look good as well? 13. Plant-based buildings If you ditched concrete, your data center could be carbon-negative

Building for a change

he data center sector is known for its conservatism. But if it is to respond effectively to the climate emergency, it urgently needs to rethink its buildings

On some measures, the global construction industry causes more global warming than any other sector. It accounts for 38 percent of the world's energy-related CO2 emissions, according to UN figures. If we are to reach net-zero in time to limit the world's rise in temperature, we have to rethink construction urgently. There are alternatives to concrete and steel, which can reset the scoreboard, turning construction from a source of greenhouse gases into a carbon sink.

Climate-positive buildings

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In simple terms, plant-based materials could store carbon while concrete and steel generate it (p14). We have the technology to make buildings which have a net positive impact on the climate. But you don't see many netpositive buildings in the world yet. Why not? Because the alternative materials are not well established. Architects and designers don't trust them, because they don't have a track record. Often, the alternative materials have not passed certification, so it's not legal to use them. Here is where the digital sector has a real opportunity to help. Data centers are a small proportion of the world's buildings, but they are built and operated by a forward-looking and innovative community.

Low carbon construction needs flagship projects, if it is to start making headway. And the data center sector is in a position to create those projects, as well as helping to get alternative materials through the hurdles of approval. The logic of the data center industry is building low-margin sheds for hyperscaler customers. But those customers are among the world's most profitable businesses. Surely it is possible for them to invest in low-carbon buildings, as a way to make good on their environmental promises?

Design issues Meanwhile, the physical look of data centers is going to become more important as they integrate with other aspects of our environment. Edge facilities, by definition, need to be close to people, so they need to be designed not to alienate their neighbors. For this reason, architecture, in the sense of the design of a building, is more important than ever (p10).

The subsea frontier Underwater data centers have been a surprise hit in recent years. Microsoft's initial efforts with Natick proved interesting, but might have been little more than a science project, if China's Highlander had not seen the potential, and a few regional authorities wrote seabed facilities into their five-year plans. But how do you build underwater? We can glimpse Microsoft and Highlander's ideas, along with a radical alternative, still at the concept stage (p14).

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Building underwater Peter Judge Global Editor

Projects in the US and China have shown that data centers underwater could be more efficient than those on land. But how do you build them?

ata center construction is a specialized task, and builders have evolved particular ways to handle it. But what would you do if you suddenly had to build a data center underwater? It’s a serious question. Tests in the US and China have shown that pressure vessels on the sea bed could deliver data center services - and provide benefits in terms of reliability and efficiency. Commercial roll out has begun, and engineers are working on the practical issues. Launching Microsoft’s Natick It all started with Project Natick, a Microsoft project which served some Azure workloads from an eight-foot (2.4m) cylinder, 30ft (9m) underwater off the Pacific coast of the US in 2015. Microsoft followed up in 2018 with 12 racks of servers in a container 12m long, which ran for two years in 117 feet of water in Scotland’s Orkney Islands. Phase 2, the Scottish experiment, was focused on “researching whether the concept is logistically, environmentally and economically practical,” so it took several steps which approached towards an actual commercial construction model. Microsoft subcontracted the build process to Naval Group, a 400-year-old French marine engineering company, with experience in naval submarines and civil nuclear power. The Microsoft team presented Naval Group with general specifications for the underwater data center and let the company take the lead on the design and manufacture of the vessel deployed in Scotland. This included the creation of interfaces to other systems such as its umbilical cable, and the delivery of the actual system. “At the first look, we thought there is a big gap between data centers and submarines, but in fact they have a lot of synergies,” commented Naval CTO Eric Papin at the time. Submarines are basically big pressure vessels that have to protect complex systems, maintaining the right electrical and thermal conditions. Naval Group used a heat-exchange process already in use for

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Construction Supplement cooling submarines. It pipes seawater through radiators on the back of each of the 12 server racks and back out into the ocean. The size of Natick Phase 2 was chosen to make an easy journey towards commercial deployment. Like many landbased data centers, the Natick vessel was designed to have similar dimensions to shipping containers used in ships, trains, and trucks. The data center was bolted shut and tested in France, then loaded onto an 18-wheel articulated truck and driven to the Orkney Islands, including multiple ferry crossings. In Scotland, the vessel was fixed to the ballast-filled triangular base which would keep it on the sea bed. A gantry barge then took the data center, and was towed out to sea to the eventual deployment site. Microsoft said the experiment was a success. In particular, it found that its Natick servers failed eight times less often than land-based ones, because they were immersed in a nitrogen atmosphere and weren’t disturbed by any engineers. What happened to Natick Phase 3? After claiming success for Natick Phase 2, observers expected Microsoft to move straight on to a more commercialized deployment Indeed, the company promptly patented the idea for a giant “reef” of containers holding servers, and things looked interesting. One image of “Azure Natick Gen 3.12” circulated, suggesting a step-change in capacity. The design shows a 300m long steel frame, holding 12 data center cylinders similar to that from Phase 2. A figure of 5MW for the total structure has been suggested - and that’s in line with a pretty low power density for the 144 racks it could hold. If that’s not ambitious enough. Microsoft has suggested it could group multiple 5MW modules together to create underwater Azure availability zones. As you’d expect from a project transitioning from test to development, there are new practical aspects to the design. Each frame has two long ballast tanks which can be filled with air, so the unit can be floated into position without support vessels. Once on site, the tanks can be filled with water to sink it to the sea bed. Despite these details, Microsoft has said very little about any third generation of Natick, and declined DCD’s invitation to elaborate. But Systems Engineering students at the University of Maryland were asked to analyze the likely lifecycle of

an underwater data center from need, through operations, to retirement. One resulting essay, published on Medium said: “A Natick data center deployment cycle will last up to five years, which is the anticipated lifespan of the computers contained within the deep-water servers. After each five-year deployment cycle, the data center would be retrieved, reloaded with new computers, and redeployed. The target lifespan of a Natick data center is at least 20 years. After that, the data center is designed to be retrieved, recycled, and redeployed.” While Microsoft is keeping tight-lipped about any plans to commercialize its ideas for underwater data centers, it did include some Natick ideas in the Low Carbon Pledge, a promise to give free access to a raft of patents designed to make data centers more sustainable. Over to China Meanwhile, the next move in the underwater data center race came from China. A company called Beijing Highlander launched a four-rack test vessel at the port of Guangdong in early 2021, and ran live China Telecom data on the servers later that year. That same year, Highlander quickly followed up with a bigger test at the Hainan Free Trade Port, and announced the world’s first commercial underwater data center would be constructed from 100 of its data cabins, networked on the sea bed, connected to land by power-anddata cables, and powered by low-carbon electricity from Hainan’s nuclear power station. Coastal regions of China are adopting the idea of underwater data centers. The concept is included in the fiveyear economic plans of several Chinese regional authorities, including the provinces of Hainan and Shandong, as well as the coastal cities of Xiamen and Shenzhen. In Hainan, contracts were signed to deliver the data center in January 2022. Like Microsoft, Highlander engaged a

more experienced marine engineering partner to handle the actual construction of the eventual data center. As its name suggests, Offshore Oil Engineering Co (COOEC) is a marine firm with a history in the oil industry. It announced its partnership with Highlander in a release that makes it clear it sees the data center project as part of a move from the oil industry to a low-carbon strategy. COOEC says the Hainan data center project will allow it to "expand from traditional offshore oil and gas engineering products to new offshore businesses." Other than that, it says it is keen to enter green marine engineering industries such as offshore wind power. The company says it is working on data cabins at its Tianjin Lingang manufacturing site, to be deployed in 20m deep water off the coast of the Hainan Free Trade Port. The announcement says the cabins will weigh 1,300 tons (the equivalent of around 1,000 cars), and be connected to land via a “placenta” tank with a diameter of 3.6 meters. COOEC says this will make it the world's largest submarine data cabin - though as far as we know at DCD, with

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the retirement of Natick Phase 2, it will be more or less the only submarine data cabin besides the smaller Highlander test vessel. Details are emerging about the efforts COOEC and Highlander are making to deliver an engineering solution to the problem of underwater data centers, which can be constructed in volume. COOEC says the cabins will be “innovative marine equipment,” and will have to be constructed to withstand the sea pressure. The system will also have to resist corrosion. The cabin will hold sophisticated electronics, and will need a large number of openings for pipelines and cables to pass through. All of these will need highpressure, non-corroding seals. “From scheme research, engineering design, construction to testing, there are very big technical challenges,” COOEC says. In one small additional detail, COOEC says the external circulation pipework will be recyclable.

COOEC will handle the design of the vessels, procurement of materials, manufacturing, and testing. It will also manage the land transportation of the modules and ships to take them to their eventual working environment. Highlander says the system will consume no water, and will use less energy. Despite the amount of steel involved in the cabins, the two companies say the underwater facility will have a lower construction cost than a land-based one and (obviously enough) will save on the use of land. Like Microsoft, Highlander praised the reliability of underwater servers. In particular, "It is a new type of marine engineering that effectively saves energy and resources and integrates technology, big data, low carbon, and green, and has far-reaching significance for promoting the green development of the data industry," COOEC and Highlander say in their press release.

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Let’s go deeper! While Highlander is the front-runner in actually deploying underwater data centers, a rival US firm is promising to set a depth record - at least in principle - for a concept announced early in 2022. Microsoft and Highlander have not spoken of going any deeper than 120m (400ft), but Texas-based Subsea Cloud claims it will go way deeper, to 3,000m (9,850ft). Subsea says it wants to take its liquidcooled underwater data center pods (UDCPs) to these depths for security reasons, so they will be safe from interference by divers and submersibles, which cannot reach those depths. "You can’t [access these pods] with divers,” said CEO Maxie Reynolds. “You’re going to need some very disruptive equipment. You can’t do it with a submarine, they don’t go deep enough. So you’re gonna need a remote operated vehicle (ROV) and those are very trackable. It takes care of a lot of the physical side of security.” Reynolds has a background in marine engineering and security penetration testing, and claims her engineering partners, connected with offshore technology company Energy Subsea, have pressure-tested the pods to show they can work at 3,000m. We’ve got a big caveat here: Subsea has not shared very much about its pods or how they were tested. Despite that, it’s a proposal that offers interesting challenges to anyone involved in the field - and suggests that this emerging idea could still

Construction Supplement change radically. Instead of heavy-duty pressure vessels, Reynolds says Subsea is working on simple, lightweight pods which will each hold around 800 servers, and have a "far more simple and proven design” than Microsoft or Highlander. Though the pods are designed to operate at very high pressure, she says they “don’t use pressure vessels (a competitive advantage for us).” At sea level, every square inch of a surface is subjected to a force of 14.6 pounds. This is atmospheric pressure. Under the sea, pressure increases rapidly at one atmosphere every 10m; so at 3,000m, a shell designed to keep that pressure out would have to withstand 300 atmospheres of excess pressure. “Both Highlander and Microsoft have opted to use pressure vessels. This design matters because the deeper data centers go into the oceans, the more pressure they incur,” says Reynolds. “To withstand the pressure they incur, they must make the walls of the data centers thicker. This affects many elements of the logistics on land and the deployment subsea.” If you don’t attempt to recreate conditions on land, you can allow the pressure to equalize, inside the vessel, and you no longer have to have such a physically strong structure. Subsea has shared a photo of its system - a square yellow container that looks sturdy, but is clearly not a pressure vessel. Visible openings in the box are presumably designed to allow pressure to equalize. The electronics must be able to work at a high pressure, probably immersed in some sort of oil. “As subsea engineers, we've designed ours to be versatile whilst maintaining its design integrity. The data center pods will work in shallow depths just as they will at deeper depths. The design ensures that at any depth, the pressure inside the housing is equal to the pressure outside – we make no changes to accommodate different depths because we don't have to.” To sum up, she says: “We designed the solution based on subsea engineering principles, not on submarine engineering principles (broadly speaking).” Construction developments Noting that modular construction is already used in land-based containerized data centers, Reynolds predicts that underwater installations could leapfrog to new levels of prefabrication: “this type of construction isn’t held back by legacy manufacturing issues and the industry, as well as the businesses that it supports need to scale quickly.”

She also points out that modular construction processes are well established offshore: “Historically, modular construction has been the norm subsea. Things must be fabricated in sections and laid in sections.” Some of the other parts of construction are also easier, because the sea bed does not already have buildings and other infrastructure installed, she tells DCD. “If you think of the complexities of laying cables to data centers on land, it is resource-intensive and expensive (it could cost millions per mile). It faces many bureaucratic and logistical challenges,” she says. “A cable deployed subsea takes a matter of weeks and actually costs less. Laying a cable subsea can cost as little as $50,000 per mile. It’s counterintuitive.” If underwater data centers ever reach bulk production, that will cut the costs, she says: “Most everything is cheaper in bulk.” While Natick had to ship one module from France to Scotland, and then charter a boat to tow it to sea, future deployments would plan for shorter travel, and deploy in larger numbers. “It will be more efficient to deploy in large numbers simply because connecting to existing infrastructure needs a vessel, which has a day rate,” says Reynolds. “You want to lay as many as you can in one go. A vessel can typically carry 80 units. It is more economical to use it to its full capacity.” While Subsea’s pods are designed for deep-sea deployment, they will operate just as well in shallow water, though they might have to be buried for security, says Reynolds: “The specs of each pod will not change for us, deep or shallow. Installation engineering will change.” For instance, in deep water, the pods will have to be maneuvered into place using a thruster tool, while that won’t be needed in shallow water. With large concentrations of underwater pods, it will be possible to

locate a maintenance vessel nearby. Small lightweight pods can be pulled to the surface quickly to be worked on. “If we deploy in a large cluster, let’s say more than 20 pods, there will be a nearby maintenance vessel which will react to large faults or disturbances,” she says. ”To disconnect, recover, replace servers, redeploy, will take us around six to eight hours.” But most underwater data centers will have spare hardware in place, so operations can be rerouted without having to bring the module to the surface: “We have redundancy in place for all pods. I presume any other company in the space will offer similar and they will also see the benefits of different classes of monitoring.” It’s sometimes asserted that the sea is governed by different rules, generally aimed at controlling fishing and mineral extraction. Data center operators may hope that they can be free of tiresome zoning rules created for land-based buildings, but they may still have planning headaches. “In the US and Asia, planning permission will not necessarily be easier, unfortunately,” warns Reynolds. “The governing system for subsea permitting is underdeveloped relative to future needs, but it will catch up as the industry shifts.”

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Building the largest data centers

emand for data center capacity has grown exponentially in recent years. While the scale, speed of delivery and technological advancements have progressed significantly, the principles of how we work remain unchanged. We adhere steadfastly to Kirby’s core values of People, Safety, Quality, Delivery and Value. These priorities have guided us since the company’s foundation and inspired us to learn and grow as an organization. As we take on more ambitious projects, we refine and hone the skills we’ve developed to take us this far and use them as a foundation for the next level. Prefabrication and modularisation have been gamechangers for Kirby since we began investing in this area about twenty years ago. We now review each new project

through the lens of maximising off-site fabrication in advance. Early collaboration with the project team is key to this, which can bring multiple benefits: •

educed on-site construction R duration

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educed management costs and R risk

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igher quality of final product is H more efficiently achieved in factory environment specifically set up for fabrication

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ean manufacturing in factory can L generate additional cost savings

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educed duration of on-site R commissioning

For example, when a confidential client in Dublin awarded Kirby the contract to deliver the full electrical and mechanical installation for a 60MW Hyperscale Data Center, one of the first tasks we undertook was to examine the plans to see how we could implement modularization to the benefit of the project and client. We soon realized that the internal electrical switchrooms were the perfect option for this type of construction. Working with the other parties involved in the contract, we agreed to prepare fully modularized Data Center switchrooms that could fully integrate the equipment and be prepared off-site. Our digitalized services came into their own as we used them to maximize the space available for racks while ensuring appropriate space was available for features and services like maintenance, access to

Kirby Group Engineering | Advertorial

equipment, and circulation. The modularization approach also meant tasks could be completed independently of progress on the site itself - there was no need for the crews on the ground to reach a certain point before our teams could get to work on the switchrooms. From there, our focus on collaboration and communication became absolutely critical, to eliminate waste, promote a safe environment and build right first time. Each contractor had to be on board with the process and get regular updates on the project. To manage this, Kirby took on the role of Lead Coordinator to bring the various moving parts together. We hosted all data around the plans and 3D modeling online so every tiny detail was accessible to anyone who needed it in real-time. Construction within the controlled manufacturing facility we used eliminated the issues that can crop up on building sites, which meant we were able to deliver products that had already undergone extremely thorough quality testing. That delivery process was a hugely exciting part of the project. Each component weighed over 20 tonnes, was 26 meters long and nearly 5 meters wide. Working closely once again with our partners on the job, we successfully transported them from Derry to Dublin for installation.

Once again, the information we hosted online and shared with each contractor served us well. We were even able to upload any data about on-site variance onto our cloud-based hub which helped us to install entire electrical switchrooms in just a matter of days. 20,000 labor hours on this project were completed off-site. It is essential that the procurement strategy around the capital equipment is aligned to this off-site manufacturing philosophy, if not, the benefits in terms of schedule and overall efficiency can be limited. Kirby Group Engineering is fully committed to this kind of manufacturing process for the future, which is why we have been investing heavily in establishing our own prefabrication facilities in the Irish midlands. These are integral parts of our offering, which give us the edge in giving clients more efficient, safer, and better quality results. It also works in tandem with another element of our vision for the future. During a multi-million euro upgrade to our company headquarters in Limerick, recently we installed a state-of-the-art Digitization Lab where we really bring our projects to life at every stage using an impressive augmented reality platform. The combined potential of these forward-thinking steps and the benefit of almost 60 years’ experience will stand Kirby in good stead for the exciting years to come.

Do we need architecture? Data centers have a job to do. Why do they have to look good as well? Peter Judge Global Editor

ata center buildings don’t get much love. They are often unnoticed and invisible. If people ever become aware of them and make any comment at all, it is most likely a sneer. "Data centers are like uncanny offices," says Tom Ravenscroft. That’s actually a compliment, because Ravenscroft is a rare example of a data

center architecture fan. But what the editor of Dezeen, the largest architecture and design magazine, likes is their unsettling strangeness, their contradictions. Uncanny offices As an architecture student, Ravenscroft’s Master's project was an exploration of London's hidden data centers, sparked by seeing a building in Lewisham, South London.

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The six-story block had windows and looked like some sort of uninspiring office block. But windows were blank, no staff came and went, and there were no cars in the car park. He found out this was Citibank’s London data center, and he began to uncover data centers hidden all over London. The Wordpress blog documenting his travels is still available, and he has led walking tours of London’s data center sector.

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these provided.

"These buildings have reflective windows, they are dirty and they look neglected,” he said at a London exhibition about data center architecture. “And yet, they have high security." Ravenscroft sees urban data centers as buildings trying so hard to be anonymous they are unmistakable. Architecture winner Others find things to like about data centers. DCD has issued a series of awards to Beautiful Data Centers, or those with particular architectural merit. This year’s winner was Ashton Old Baths in Greater Manchester UK, a 19th-century municipal public swimming bath, which was closed and lay empty for 40 years, before Tameside Council converted it into a tech hub, with 10,000 sq ft of office and coworking space, and a 200kW data center. The finished product looks special because of a factor that made the data center difficult to install. The building is Grade II* listed by Historic England for its architectural merit, putting it on a par with the iconic Battersea Power Station in London. That put a strict limit on what the data center builders could do. “As engineers we tend to try and put holes everywhere for ducts and so forth,” says data center designer Zac Potts, at Sudlows, the firm that built the Ashton Old Baths data center.

“We had to meet the requirements of the engineering perspective, and restrictions imposed because of the building’s heritage,” he said. “We needed apertures and penetrations cut out of the building, but we had to work within the original windows and doors to route services out without damaging what is left of the building.” There were restrictions on planning: “We couldn’t drop surprises with our ductworks. All the penetrations had to be planned out quite meticulously. "We had to send information through to the heritage team, and there were lots of hoops to jump through. Every detail had to be approved.” The Council’s heritage team were keen to prevent damage to the existing building, and make sure everything had to balance with the existing colors and styles. To meet these demands, architects Paull and Robinson designed a freestanding wooden “ark” structure independent of the building shell to hold the new office space and the data center. Sudlows and the engineers had to work closely with the architects to make it work. Is old better? Many of the data centers that feature on DCD’s award shortlists were installed in existing spaces, where they had to make the best of the limitations and opportunities

"As they mushroom across the globe, it’s time we thought of data centers as a peculiar - and peculiarly challenging - new building typology."

In Stockholm, Bahnhof’s Pionen data center turned a former nuclear bunker into a glossy lair high-tech lair worthy of a James Bond villain. The MareNostrum supercomputer nestles its server racks into the warm-hued stones of a 19th-century church, on the campus of the Polytechnic University of Catalonia in Barcelona. Another church, the Salem Chapel in Leeds, became a data center where the servers are installed on the ground floor of the old worship space. The balcony was kept, and turned into a conference auditorium, looking down on the data center through a new glass ceiling. But retrofits are a tiny minority of data centers. Vastly more are in new buildings, which have to meet multiple demands. They have to fit in with their surroundings, satisfy planning regulations, and also please any local residents - all alongside the need to satisfy the technical requirements of the data center. And underlying all that, they have to meet a budget. Architects are a big part of that. A new building type? "Data centers power modern life and yet they’re rarely considered as pieces of architecture," said Clare Dowdy, curator of the recent London gallery exhibition of data center architecture, Power House. "But as they mushroom across the globe, it’s time we thought of data centers as a peculiar, and peculiarly challenging, new

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building typology." Potts, like most data center builders, has more modest aims: “Newly-built data centers, are usually pretty ‘nice’ buildings, but from an architectural point of view they are normally fairly understated.” Young tech companies may want a stateof-the-art building, but they don’t want to show off their data center. They want the building discreet, partly for security reasons, so it doesn’t attract attention from vandals, terrorists, or environmental activists. That’s the fundamental reason for the “uncanny office” effect noted by Ravenscroft. A discrete look is also important for aesthetic reasons, particularly in urban areas where people will see the building. No operator wants to alienate its neighbors. There’s a tension between the engineering demands and the need for a ‘plain’ look, says Potts: “How do we integrate things like diesel generators and chillers with a plain architectural look? We also have to provide airflow and acoustics.” A good architect will be able to work closely with the engineers, and may surprise them: “From an engineering point of view we say what we need,” says Potts. “They can usually integrate that and make it into something special. They will work with colors, lines, and the edges, to produce something you wouldn’t have envisaged.”

He says: “We start with clean lines and symmetry. Architecture adds an extra layer on that.” Architects who have done similar projects should be able to help with constraints like the thermal performance of the building, so it meets regulations and operates efficiently. They can also add fresh ideas. “Working with a good architect really helps,” says Potts. “We focus on the data center aspect. An architect with some understanding of data centers can be involved at the very early stages and engage in those conversations. A good architect might spot opportunities that could be missed otherwise - perhaps suggesting where a data center should go within a mixed-use building, or where to place it in a large development. “There can be opportunities for heat reuse, or for mitigating where pipes and maintenance go,” says Potts. “Often data centers on a commercial estate can get tucked away into the most awkward position.” Getting the architect in early can help make sure the project fits: “They will consider things other than the engineering,” he says. “Our aspiration is to improve the area, through its presence. Rather than detract from it.” Budget can be an issue: “If you boil down to the absolute bare bones, you would end up with an ugly building with not much

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consideration for the area,” says Potts. By contrast, an attractive tech hub can encourage other buildings and businesses to work together. “That’s why there’s a lot of focus from master planners and developers,” he says. “Just look at the margins, and you might bet a gray box, but that doesn’t improve the area so you need to look at doing something else.” What that something is, is undefined. There’s been a trend for “exposed services” which leads to visible ducts and cables all over retail spaces. But data center operators don’t want that, except in the inside of the building where practicality is all that matters. On the outside, there’s usually not much budget for extravagant decorations, but a strong desire to minimize the impact of the building and, usually, to obscure its technical nature: “Louvers and cladding can make sure the diesels and chillers are integrated in well.” There is also likely to be some landscaping around the buildings, combining the ubiquitous security fencing with a screen of trees and some grassed banks. “We focus on the engineering constraints, says Potts, “but it’s about achieving a balance and making sure the data center looks beyond the IT, to see the potential for creating improvement to the area, instead of just taking from it.”

Plant-based buildings Concrete creates huge carbon emissions. Why can’t data center builders turn that around, and use biological material that stores carbon instead?

Peter Judge Global Editor

oncrete construction is one of the worst polluting industries worldwide, pumping out some eight percent of the world’s CO2 emissions. Data center operators make a small portion of that, but they are building very fast indeed, pouring concrete like there is no tomorrow. Operators are very keen to show their green credentials by reducing the energy consumption of their buildings when they are in actual use - they are not moving nearly so fast in cutting the emissions they create when they are being built. For instance, Microsoft and Amazon have invested in a company called CarbonCure, which pumps CO2 into the concrete as it sets, Compass Datacenters has used CarbonCure concrete in some of its buildings. However, this process only compensates for about five percent of the emissions from a given batch of concrete and it is only possible to use it in a small fraction of the concrete being used. Far more radical alternatives are possible, particularly with plant-based materials, which could actually turn the tables and make buildings carbon negative, storing carbon instead of emitting it.

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Wood Timber is a much more practical building material than many would credit. But it is one that suffers from all the difficulties any new material will have with a community as conservative and risk-averse as data center builders. Data center builder Zac Potts of Sudlows has constructed a wooden building-withinbuilding containing a data center, at the Ashton Old Baths in Manchester, but he was uncertain about the idea of building a facility entirely from wood. “There would definitely be considerations about fire risks,” said Potts, when DCD asked him about the possibility. In 2021, OVHcloud’s SBG2 in Strasbourg burnt down, and no cause has been revealed - but among the rumors circulating about it, one allegation is that the building had wooden floors. Architects who favor wood would argue differently, and point the finger elsewhere. Architect Rune Abrahamsen has built the world’s tallest timber building, an 18-story office-and-hotel block in Norway called Mjøstårnet and he told EuroNews wood’s wellknown behavior in a fire can actually be better than concrete. “Timber burns, but the good thing is that we know how it burns,” he said, pointing out that a big log on a campfire will still be there in the morning when smaller branches have gone. ”Similarly, a timber building will remain standing after a fire has gone out by itself. The charring of wood creates an insulating layer that protects the inner part of the timber.” “The charring speed is predictable,” he said, explaining that the building is made crosslaminated timber, also known as glulam. Tests have shown a structural column can burn out leaving large sections undamaged. Concrete is very different “When there is a fire, concrete will get warm and crack, which means there will be openings at the surface, exposing the reinforcement. The reinforcement is normally made of steel and when the steel gets warm it melts and loses its bearing capacity. Consequently, the concrete will collapse because it’s no good without the reinforcement.” As a modern hotel with an exhibition center and office space, Mjøstårnet has a wooden swimming pool, and will certainly also have some installed IT equipment, probably in a dedicated server room or closet. Still, that is not a wooden data center. The closest to a wooden data center can be found in two projects in Sweden. The first is EcoDataCenter’s facility in Falun, which uses cross-laminated glulam wood for the frame, walls, and roof of the data center. “You will ask me, why, wood burns?,” Jan Fahlén, EcoDataCenter site development manager, told DCD. “Yeah, it does, but laminated wood doesn’t burn that way - try to put fire on this, you won’t be able to.”

The second is the Boden Type facility built by researchers in Sweden, which uses wood for efficiency, and also to meet with environmental requirements set down by the local authority. “We laid the foundations in concrete, and we added some steel reinforcements, but the outer shell construction was wood, all the way,” says Professor Jon Summers, of RISE, the Research Institutes of Sweden. “There were some metal elements holding the main supports together.” Summers says that buildings don’t have to be entirely made from non-traditional materials: “It’s about reducing, isn’t it? If you are reducing the amount of concrete, then your carbon intensity should be lower.”

hempcrete panel for a building like that makes a lot of sense,” One of the authors, Chris Magwood, told HempBuild magazine (interviewed by city planner Adam Tate). Magwood has worked with hemp for 20 years, writing a major textbook on its use, and is the author of Essential Hempcrete Construction: The Complete Step by Step Guide. He’s not expecting Microsoft to switch

Hemp Another front runner in organic building material is hemp. Hurds or shives, a by-product of making hemp fiber can be mixed with a lime-based

binder, to create a composite material called “hempcrete.” This has very good carbon storage properties, as the organic hemp material consists of carbon fixed from the atmosphere, and the lime binder absorbs CO2 during the setting process (unlike concrete which emits it). Microsoft is reportedly considering using hempcrete to build carbon-negative facilities, having sponsored a paper on alternative construction methods in 2021, from the Carbon Leadership Forum at the University of Washington College of Built Environments The report considered hemp, alongside five other novel materials. Hemp is not suitable for load-bearing structures, but very good for insulation, with “high fire resistance, excellent moisturehandling capabilities, good carbon storage capacity, and non-toxicity,” according to the report. “For Microsoft’s data centers, they are trying to make fireproof buildings, so a

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across to hemp overnight, but its name on the report will legitimize the subject, giving it credibility. “If I’m somebody making a hempcrete material and trying to convince somebody to fund me; if I tell them I have three homeowners who want to do this, that doesn’t speak very loudly,” he says. “If I can say Microsoft is interested and they’re actually in with some money, that really makes a difference. So I’m hopeful that things like Microsoft’s interest will really help move things along faster than they might have.” Hemp cultivation was only legalized in the US in 2018, and new hemp farmers will be looking for a way to make use of their hurds, and hempcrete products can be made as likefor-like replacements to existing products, so they can be used in both new builds and retrofits, turning buildings from carbon sources to carbon sinks. “The great thing about a material like that is that it’s a one for one substitution for

Construction Supplement things that are already in the market,” says Magwood. “If your crew sticks a fiberglass batt in a wall every day, they can just stick a hemp fiber batt in.”

Mycelium, earth, and more Another material proposed in the Microsoftsponsored is mycelium, the root structures of mushrooms. The benefit of mycelium is that, as well as storing carbon, it can also be turned into wall panels or even structural mycelium tubes. Mycelium can be grown in agricultural residue or waste such as straw, hemp, wood chips, or nutshells. Many of the materials it replaces are made from petrochemicals - and tubes produced from it can even replace some structural steel. Other materials in the report include bricks made by growing algae in a mixture of sand, seawater, and cyanobacteria: “These ‘living bricks’ are a concrete-like alternative that can be grown on demand.”

It’s also possible to get bricks as a byproduct of making biofuel. The residues can be turned into stable “biochar,” which stores CO2 for very long periods. Alternatively, raw algae or nutshells can be mixed into more conventional concrete, storing carbon and making it carbon neutral. Even replacing some of the cement in concrete with unreactive fly ash can reduce the carbon it emits substantially. Some alternative materials are far more simple and traditional: hay bales and thatch can be used, and bamboo’s structural

properties are well known. Another possibility is literally much more down-to-earth. Data centers have a concrete slab floor, but the Microsoft-sponsored CLF report proposes a solution already available, under our feet: hard-packed earth slabs. “Despite centuries of historical precedent, surprisingly little research has been devoted to the idea in a modern context,” the report says.”Among those unaware of modern enhancements, the notion of an earthen floor tends to evoke associations of poverty and dirt, so the option is typically dismissed. For this reason, the making of earthen floors has remained a niche market, one not yet applied to modern buildings or seen as meriting any significant study.” Additives can give the earth floor greater durability and grip, protecting it from spillages or other eventualities.

Building a market The tough part to any of this is turning the

idea from a possibility into an actuality with a groundswell behind it. With the earth’s climate teetering on the brink, it’s just as vital to give up on polluting buildings as it is to stop using fossil fuels. But it won’t happen unless new material get credibility through prototypes like Mjøstårnet and the report’s authors think Microsoft can help here “These materials warrant realistic enthusiasm and are worthy of investment to aid and accelerate their prototyping, scaling, manufacturing, and marketable use in the building industry supply chain,” the report concludes. “In addition, opportunities exist for investment in educational and training opportunities in embedded apprenticeships in research, design, and construction labs, at manufacturing sites, and with professional design firms.” It suggests that in 2022 showcase carbon positive buildings should be put together and promoted. It might even be possible to

make quick and easy versions of Edge data centers, which could be 3D printed from new materials. There also needs to be a significant investment in getting the new materials through compliance and safety tests. That’s an expensive process, Magwood points out: “We could get all these materials through R&D, and approved in two years for millions of dollars, but in general, the people doing it don’t have millions of dollars.”

Give us a showcase That’s one role for a Microsoft or another tech giant. Once approval is gained, new materials can stand on their own two feet, says the report: “Past experience bringing cross-laminated timber and mass timber materials to market has shown that lowcarbon and carbon-storing materials are feasible and attain parity with more conventional alternatives in terms of cost, code compliance, and construction schedules.” It adds, however, that “these materials, lacking leverage on any of these fronts and needing significant investment to scale up production, have not achieved mainstream status.” To get over this next hurdle, the concept needs a showcase, and an actual net-positive data center would be a very good one, well within the capability of a hyperscale data center builder. Microsoft stops short of promising that in its introduction: “Investing in a proofof-concept plan to bring new carbonstoring technologies to market aligns with Microsoft’s environmental values and pledge to become carbon negative in present-day operations by 2030 and to remove from the environment all carbon emitted by the company historically by 2050.” Microsoft’s actual promises are to champion low-carbon public policy, and support efforts to educate students into using new materials with an “Idea” program (Integrated Design, Engineering, and Architecture) to promote carbon-storing material, delivered through colleges and Microsoft’s Climate Innovation Fund. Magwood is hopeful: “I think there’s a really great role for them to play and it was exciting to be a part of Microsoft kind of sticking their toe in the water. That’s a real switch, for the last 25 years, alternative materials have been this really grassroots thing, so it’s really interesting to see Microsoft make these really bold climate commitments they now have to figure out.” But actual data center designers warn it will be an uphill struggle, when delivering an IT service is the first priority: “It’s what we’re always up against - it’s there for the IT,” says Potts. “Keeping the space clean and safe is the number one priority, and it’s hard to justify new materials.”

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