31 October 2025

Abhishek Kamerkar, Senior Global Product Manager, Fluke Corporation

Data centres rely on hundreds of humidity sensors to provide real-time, precise information to meet key requirements. Even a single inaccurate reading can cost a data centre millions of pounds in downtime, penalties, and equipment damage. Proper calibration is essential to ensure these sensors deliver trustworthy data, but data centres face significant challenges when calibrating these devices.

Turning up the dial on humidity control

Humidity below recommended levels creates a higher potential for electrostatic discharge, increasing the risk of damage to sensitive electronic components. This can lead to shortened equipment lifespan, increased costs, and lost revenue. Experts estimate the cost of electrostatic discharge (ESD) damage in the electronics industry is at least half a billion each year. Conversely, humidity above this range can cause condensation buildup, resulting in equipment damage, electrical shorts, and corrosion.

Humidity control is preventive protection that safeguards uptime, preserves infrastructure investments, and ensures the environment remains stable enough to support the nonstop demands of modern data processing. Effective humidity control plays a vital role in safeguarding sensitive data, upholding Service Level Agreements (SLAs), and avoiding costly equipment damage.

Calibration: the heart of effective maintenance

Even the most stringent humidity monitoring protocols are only as accurate as the sensors taking the readings. Sensors can drift over time, and the humidity percentage displayed on the monitor may not be accurate.

In a data centre environment, even short-term inaccuracies can have significant consequences, especially when SLAs are involved. A single deviation, even one caused by a faulty sensor, can trigger a cascade of issues that undermine both compliance and credibility.

Inaccurate readings can prompt unnecessary HVAC adjustments, destabilising the climate and putting equipment at risk. Overcooling or excessive humidification due to inaccurate sensors can drive up energy use and operating costs unnecessarily. In large-scale facilities, even small inefficiencies can scale into thousands of pounds per year in wasted energy. Proper calibration ensures HVAC systems respond only when needed, helping data centres reduce their carbon footprint and reduce utility costs.

Just as critically, these false readings can be logged as environmental violations potentially breaching SLA terms, even if the actual conditions remained within the correct range. For data centres supporting industries like healthcare, finance, or government, these missteps can also lead to audit failures or regulatory scrutiny.

Properly calibrated humidity sensors are a frontline defence against SLA breaches and operational misjudgements. By ensuring humidity sensors are correctly calibrated and providing reliable readings, data centres can protect the integrity of their services.

There is no one-size-fits-all frequency recommendation for humidity sensor calibration. However, many data centres opt to perform calibration on an annual basis. For data centres located in particularly humid environments, more frequent calibration, such as semi-annually, may be prudent.

However frequently calibration is performed, the calibration must be documented and traceable. The documentation must be able to stand up to internal audits, SLA verification, and regulatory inspections. Each humidity sensor must have a traceable calibration record, showing when it was last tested, the reference standard used, and whether it passed or required adjustment.

Making sense of sensor calibration

Calibration doesn’t come without its challenges, however, especially when it comes to the accessibility required for it.

Humidity sensors in data centres are typically located in critical areas such as the white space, server racks, air handlers, and return ducts, locations that are essential for accurate environmental monitoring but often hard to access. These zones are protected by strict security protocols designed to safeguard sensitive data and equipment. Staff often face layers of clearance requirements, tightly controlled maintenance windows, and the need to coordinate with both facility and IT teams to ensure operational continuity during calibration.

These restrictions introduce real-world complications into what might otherwise be a routine process. While many data centres elect to outsource their sensor calibration, this process can introduce several challenges.

First, to maintain security in highly sensitive white space areas, any contractor and its employees must be thoroughly vetted and their access carefully controlled and scheduled. Second, for data centres that elect to send sensors to an outside lab for calibration, the timeline and logistics are largely controlled by a third party, making it challenging to comply with internal maintenance schedules. Third, sending devices off-premises poses inherent security risks from third-party personnel and their internal procedures. And finally, costs for calibrating hundreds of sensors annually can quickly escalate, limiting the centre's ability to invest in growth.

Unity between compliance and operations

Data centres continue to grow in scale and criticality, and as they evolve, the margin for environmental error continues to shrink. To better meet environmental requirements, accurate humidity monitoring is essential. However, the results provided are only as strong as the sensors behind them. It is therefore vital to ensure those sensors are regularly and properly calibrated.

These calibration processes are responsible for preserving secure environments, meeting documentation requirements, and maintaining the high stakes of uninterrupted operations. Regardless of whether this is handled in-house or outsourced, businesses must ensure these key processes are handled effectively. Investment in proper tools, training, and traceable calibration practices are crucial for data centres, helping them take full control of their environmental monitoring – protecting their integrity, reliability, and reputation.

With data centre investment growing across the UK, smart environmental monitoring practices are more important than ever, and perhaps just as critical as the servers themselves. It is time to prioritise calibration to future proof operations as demand for data centres will only continue to increase.