Rising relative humidity rates across the UK are presenting challenges for the construction and maintenance of a range of buildings, not least data centres. With critical infrastructure requiring particular humidity levels for optimal operations, Billy Durie, Global Head of Sector – Data Centres at Aggreko, discusses best practices in temperature and moisture control for data centres.
Due to the sensitivity of their systems and equipment, data centres have a specific relative humidity level in server rooms to maintain in order to maintain uptime. However, as heavy rainstorms and increasingly hot temperatures are becoming ever-more frequent in the UK, high humidity is an issue that will present continual challenges to data centres for the foreseeable future.
Climate change is a key concern for many data centre professionals, particularly amid pressure to alleviate the impact that facilities themselves have on the environment. According to the UK's National Centre for Atmospheric Science, Europe has been warming significantly fast compared to the global average. Where moisture in the atmosphere is concerned, the UK have been experiencing average annual humidity levels of 73%, well above the comfortable relative humidity level, which rests between 40% and 60%.
A relative humidity level of above 60% deems a space to be uncomfortably wet, creating an environment which has too much moisture. This could result in the damaging of expensive electrical materials and therefore additional repair costs, long delays, and in some cases irreparable damage. Anything below 20% is uncomfortably dry and can result in damage to building fabric itself, as well as server equipment.
Studies relating to climate change indicate that the humidity issue could become more severe. According to the European Union, climate change is likely to increase flooding, rainstorms, droughts, and high temperatures across Europe. Further to this, climate change is also causing shifts to humidity. According to Kate Willett, Met Office scientist and author of a study looking at global humidity, humidity levels are increasing consistently with the warming of the planet.
For the data centre market, high relative humidity and flooding is a problem that can affect a facility in both its construction phase and long into its working life. The first major issue to consider is how humidity impacts critical electrical components. When a data centre is constructed, the electrical distribution system must be kept in an environment that is dry and within a certain temperature band. Failure to do so could void any warranties, adding significant cost to a job. High relative humidity and moisture can also lead costly damages, including metal corrosion and prolonged time for paintwork, adhesives and cement to dry or cure. It can also impact the speed at which the building deteriorates.
As moisture can find its way into the smallest areas and spaces of any component, it is imperative that the right building conditions are maintained throughout every stage of a data centre’s construction. Humidity fluctuations should also be avoided. If a building is incorrectly sealed and dehumidified, it will be susceptible to future moisture-related issues. Anticipating and managing this damage is therefore crucial during the construction phase, and the good news is that it can be mitigated.
Controlling moisture on a data centre site – both during and after the construction phase – relies on a few aspects. First, selecting a location for a new data centre which falls within the recommended relative humidity percentage is ideal, but it is not always possible. When unable to avoid higher moisture levels in the surrounding environment, there are steps that can be taken to keep a facility under optimal conditions.
It is important to note that relative humidity is the percentage of moisture within an air particle. As the air gets warmer, its capacity to hold moisture grows, while cooler air has the opposite effect. To keep within 40 to 60% humidity, there are processes that can remove or add moisture depending on how far you are away from optimal levels.
Particularly pertinent after any flooding has occurred, there are three stages to remove moisture. The first is to add heat into the space to excite the molecules of water within materials. Here, molecules are drawn into the expanded atmosphere and out of the building structure. Once this phase is complete, air must be circulated using fans to aid the removal of moisture and avoid leaving the air stagnant. Then, a dehumidifier should be used to remove the water molecules. Should the data centre building become too dry, humidifiers can also be used to maintain the balance of moisture later on in the build or after commissioning.
There is a common misconception amongst industry professionals that only the winter months present high levels of humidity, however, the physical volume of moisture is the same whether it is winter or summer. Therefore, it is worth noting that humidity is a year-round challenge, which, given the increase in fluctuating weather conditions, could create future challenges for building services engineers working on data centres.
Without the appropriate support or tools, data centres could be open to permanent damage and faulty equipment. It is recommended that building services engineers assess their options and seek consultation if they are concerned about how relative humidity might impact their site. Using temperature control expertise from companies like Aggreko, building services engineers can work to select the suit equipment level to control humidity levels in the correct locations onsite. Using a rental option, also mean that the equipment is only introduced when required, eliminating outlay for permanent infrastructure and saving space.
As climate change could worsen humidity and incidences of flooding, knowing the best practice for temperature and moisture control in a data centre will become key for building services engineers working on them. To avoid long term damage and potentially even costly downtime, having processes in place and using industry consultants for expertise could help to alleviate issues that ensue from this.
For more information on how humidity impacts data centres, you can download Aggreko’s humidity guide.