Total investment in global data centre infrastructure more than doubled in 2021 to US$ 53.8 billion, according to research by global law firm DLA Piper. With demand rising for data centres, there is a growing need to put mitigative measures in place to deal with the noise and vibration they generate. Here, Juan Battaner-Moro, Head of Knowledge Exchange at KP Acoustics Research Labs, examines some of the most common problems and solutions for facilities managers working in this area.
Our increasing reliance on IT infrastructure means the rapid growth of data centres will continue unabated. In the UK, highly populated urban locations, like London, expect growth in brownfield data centre construction in the coming years, with greenfield investment taking place in other cities according to a recent report from ResearchAndMarkets.
However, facilities managers need to be aware of the potential for noise and vibration that arises from this infrastructure. Acting at the earliest possible stage, ideally during the design phase of any new data centre, is the best approach. Retrospective solutions often require temporary shutdowns to install equipment like isolators, which is far from ideal when dealing with mission-critical infrastructure.
Sources of noise and vibration
In order to ensure 24/7 operation, backup power is essential. However, this can be a major source of noise if not properly treated. Some plant rooms can generate in excess of 110 dB, so this noise needs to be carefully contained. The low-frequency hum created by transformers can also be an issue if located close to office facilities.
To function properly, the computer hardware in a data centre requires controlled environmental conditions. Too much heat, for example, is a major issue. Google reported it was forced to temporarily shut down some of its data centres in London during last year’s record-breaking heatwave.
For this reason, data centres also contain a lot of equipment that deals with heating, ventilation and cooling (HVAC). The potential noise and vibration generated from this equipment should ideally be considered at the design stage, where specifiers can choose equipment based on an understanding of this problem.
The air that passes through inlet and outlet vents and associated ductwork can create noise problems, particularly at high-flow velocities. The rotating elements in mechanical equipment like fans can be a major source of vibration which, depending on the location of the equipment, can be carried through a building’s structure.
The extent of the problem varies depending on the location and type of facility. A common problem is HVAC equipment in office buildings generating noise for the building’s occupants. If you are trying to have a conference meeting on the top floor of a multi-storey building, this might be quite difficult if you have HVAC equipment mounted on the roof.
A less common issue is when neighbouring facilities house sensitive scientific or medical equipment. This problem is common in hospitals or universities. Microscopes, for example, are sensitive to vibration levels far below what the human senses can perceive.
For standalone facilities, you avoid the problems above, but you need to consider whether the outdoor noise generated from the facility is within the limits set by local authorities. The wellbeing of the local community should be a concern of any data centre facility with rooftop or outdoor HVAC components and ongoing monitoring may be advisable for this purpose.
Approaches to mitigation
If you are aware of potential issues during the design stage, this can be fed into the process of selecting the right equipment. Slower fan speeds and higher-quality balance requirements are good examples of tackling the problem at the source.
The next mitigative strategy is to consider the likely transmission path for any sources of vibration. For the rooftop example given above, a common approach would be to mount any HVAC equipment on spring mounts. Piping and ductwork in the building can be suspended on acoustic hangers. If your requirement is blocking the path of airborne noise, methods like sound barriers, acoustic enclosures or silencers may be the most effective solution. For transformers located outside, but in proximity to office workers, enclosures are often recommended.
Scenarios like medical facilities with highly sensitive equipment might require a more bespoke solution. Here, it might be necessary to isolate the sensitive equipment itself using more sophisticated approaches, like air springs.
For all these solutions, it is generally the case that retrospective action is more costly. Firstly, isolators might have space requirements, meaning installation at a later stage is not always straightforward. Secondly, the installation might often require a temporary shutdown of the data centre.
Once a data centre is up and running it might be advisable to continuously monitor. Site managers are automatically alerted if noise or vibration levels exceed chosen parameters, allowing mitigative action to be taken at the earliest possible stage. A key need here is for monitoring devices that are compact and reliable, particularly in locations where space is at a premium. Although traditional monitoring equipment tends to be extremely bulky and not ideal for a data centre, modern devices can offer more capabilities in a smaller envelope.
The rise of data centres doesn’t need to mean an inevitable increase in noise and vibration problems for facilities managers. Getting an acoustic consultant involved at the earliest possible stage for new data centres can significantly reduce the risk. For existing facilities, although retrospective action is more difficult, many simple engineering solutions can make a crucial difference.
KP Acoustics is a full-spectrum acoustics consultancy. If you are a site manager with concerns about noise and vibration from HVAC equipment, get in touch with an experienced consultant by calling 020 8222 8778 or visiting kpacoustics.com.