How hot climates challenge data centre structures

In my previous blog, I discussed the impact that cold temperatures can have on data centre structures. However, data centres also need to be built in hot climates. As such, understanding what structural decisions need to be made during the design process is key to brining a data centre online in the heat. Additionally, as climate change continues, understanding the impact of future conditions needs to be accounted for, including storms, heavy rainfall, and even snow.

As mentioned in the previous blog, the increase in global in global data centre developments has led to the widespread implementation of reference designs. These are important in speeding up the delivery of data centres across different regions. However, when bringing a reference design development to a hot climate, there are unique challenges that must be addressed. Bringing a design from Sweden to Spain requires changes to be made given that the country exists in hotter conditions and has different materials available.

As such, structural engineers must use innovative solutions to account for these high temperatures, thermal expansion, and other stressors on the building. Additionally, with sustainability becoming a much larger focus, building in hotter climates can provide a challenge to structural engineers to keep the building cool during periods of extended heat in the summer. Ensuring successful, efficient delivery requires a skilled team of engineers that understand the climate they are operating in. A reference design cannot just be copied and pasted. For a facility to remain functional in the long-term, there are techniques that need to be used.

The challenges and solutions of working in hot climates

In regions with hot temperatures, such as locations close to the equator, there are different challenges that come from the thermal actions and concrete works on the building compared to buildings in colder climates. For these projects, different materials must be involved in the construction compared to those in colder climates, in particular, taking zero carbon and efficiency in mind. Specific considerations include:

Thermal actions

Similarly to cold environments, thermal actions govern movements of the building frame and movement joint requirements. In cold climates, the buildings will be subjected to more contraction forces; in the hot environments, the buildings will be subjected to significant expansion forces. These variations in temperature cause variability in the load of the structure.

We designed a data centre on a site in a desert-like area of Spain. This required us to operate within the regulatory framework of the Spanish Technical Building Code or Código Técnico de la Edificación (CTE). Through this framework, we were tasked to design the building to withstand outside air temperatures of up to 48°C which was possible where the site operated. Understanding these temperatures is essential to designing the buildings, particularly to understand the positioning of movement joints and stability elements and to minimise the tonnage of steelworks to reduce embodied carbon.

Concreting

When concreting in hot temperatures, the heat can affect the construction programme as it impacts scheduling. For example, the curing time for concrete needs to be considered. Given that the speed of construction is one of the biggest factors for clients, finding the optimum time to get concrete in place is essential for data centre projects.

To account for these impacts, designers must operate by local regulations. The Spanish regulations include not pouring concrete when air temperatures are above 40°C. At these temperatures, water can evaporate quickly, resulting in an increased risk of cracking and compromises the durability of the concrete in the foundations of the building.

Oftentimes, this will result in the concreting taking place at night when temperatures are lower or by incorporating manual cooling practices like shading to get the concrete to lower temperatures.

Solar radiation

The radiation from the sun needs to be accounted for during design. Increased sunlight can increase the surface temperature of the building, resulting in thermal expansion which will lead to increased stresses in the structural materials. This factor can heavily impact the choice of materials for the building, in particular, with the choice of insulation to reduce the stresses on the structural elements.

To mitigate the effects of solar radiation, structural engineers should be experienced in choosing local materials for heat and UV resistance. For example, lighter colours for the exposed elements to the sun is a good practice as it attracts less solar radiation. In addition, by working with manufacturers who have tested and certified the materials to suit the environment, they can produce the most robust insulation surfaces.

How could climate change affect future climate conditions?

The trend of increasing global temperatures and extreme weather conditions has impacted the design of data centres. Since these buildings are expected to be operational for at least 50 years, ensuring that the new builds created now can account for future weather trends is critical. This is particularly important in locations where extreme weather is expected to occur, such as storms, droughts, or heavy rainfall. To accommodate these, structural engineers need to address specific challenges:

Storms

The effects of storms on buildings are readily apparent. They come with increased wind speeds, which naturally put buildings at risk. These increased wind speeds can impact the lateral force exerted onto a building, resulting in temporary movement of the building. Whilst the impact of such wind forces typically leads to building movement rather than safety concerns, it can still impact the outside of the data centre and even the internal equipment.

To manage this risk, structures need to be designed for increased variable wind loads. Regulations and research predict the possibility of these variables to at least a 50-year level, which needs to be used during design. The choice of materials plays a critical role here, as they need to be able to accommodate the increased load on the building and the effects of high wind speeds.

Temperature variations

The rise in global temperatures has already impacted the data centre industry. When temperatures hit record highs in the UK, data centres designed for lower external temperatures couldn't operate as efficiently during these extreme periods. Whilst steps are being taken globally to reduce the impact of climate change, data centre facilities need to be designed considering the chance of extreme temperature variations. In both hot and cold climates, the increased level of expansion and contraction of materials from thermal actions could result in cracking or significant movements in the building.

Designers need to manage the conditions of the structure and make plans for the foreseeable worst-case scenarios. This can help reduce the need for costly retrofitting later down the line. The temperature range considered for the building design should expect to exceed any variation both during construction and in-use.

Heavy rainfall and snow

Increased rainfall and snow in certain climates can apply a larger force on the data centre's roof. An increased risk of structural damage or failure comes with an increased force. The increased load can result in the deflection or bending off the structural elements themselves, therefore choosing suitably resilient materials is needed. Whilst it would typically require extremely high forces to cause structural failure, the performance and appearance of the structure are a consideration during extreme rainfall and snow events.

Currently, data centres are designed to meet regulatory requirements that detail elements like snow load within a 50-year return period and appropriate loading safety factors. This ensures that roofing can handle any expected snow or rainfall load without significant structural risk. However, operators should ensure the maintenance of drainage systems to reduce the risk of damage to the building during these extreme weather events.

Experience is the best risk mitigator

Reference design developments are an important way to speed up the delivery of mission-critical infrastructure. By bringing a working design to new regions, data centre operators can bring facilities online faster. However, when operating in different areas around the world, individual climatic conditions need to be addressed.

By partnering with an engineering team that is experienced in working with these conditions, data centre operators can reduce the risks that come from these variables. During design, mitigating risk and reducing embodied and operational carbon are large factors that could cause delays in delivery. At Cundall, we have many years of experience operating around the world in different locations, working with material manufacturers and regulators to understand the different approaches that each facility needs. As the climate continues to change, the structure of data centres will need to change too.