The ideal temperature range for both data centres and server rooms, as recommended by ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers), is between 18°C and 27°C Celsius (64°F and 80°F Fahrenheit). This range helps prevent overheating, reduces thermal stress on components, and ensures consistent performance. Similarly, humidity levels should be kept between 40% and 60% (ideally 45% and 50%) to prevent risks associated with both low and high humidity. Deviations from these parameters can cause overheating, condensation, static electricity buildup, corrosion, and dust accumulation, all of which negatively impact equipment.
Data Centre & Server Room Temperature and Humidity Monitoring Systems
Temperature is the measure of how hot or cold something is, reflecting the average kinetic energy of the particles in a substance. It plays a crucial role in natural processes, such as the ability of air to hold moisture. Warm air can hold more water vapour than cold air.
Temperature is typically measured in Celsius (°C), Fahrenheit (°F), or Kelvin (K). Here are the conversion formulas:
- Celsius to Fahrenheit: F=(9÷5×C)+32
- Fahrenheit to Celsius: C=(F−32)×5÷9
- Celsius to Kelvin: K=C+273.15
- Kelvin to Celsius: C=K−273.15
Relative humidity (RH): is a measure of the amount of moisture (water vapour) in the air compared to the maximum amount of moisture the air could hold at a given temperature. Relative humidity is expressed as a percentage (%), and it tells you how much moisture the air contains relative to the maximum it can hold at that temperature.
100% RH means the air is fully saturated with moisture and cannot hold more water vapour, while 50% RH means the air holds half of the moisture it could at that temperature.
The formula for Relative Humidity (RH) is:
RH=(Actual Water Vapour Density÷Saturated Water Vapour Density)×100
Where Actual Water Vapour Density is the amount of water vapour in the air, and Saturated Water Vapour Density is the maximum amount the air can hold at a given temperature.
Interrelationship of Temperature and Humidity in Data Centres and Server Rooms
In data centres and server rooms, maintaining the correct environmental conditions is crucial for the efficient operation of IT infrastructure, ensuring the performance, reliability, and longevity of hardware. Temperature and humidity are two key factors that directly influence the functionality and durability of electronic devices in these environments.
The interrelationship between temperature and humidity is significant: as temperature rises, the air’s capacity to hold moisture also increases. This means that warmer air can hold more water vapour than cooler air. Relative Humidity (RH) is the percentage of moisture in the air compared to the maximum amount of moisture the air can hold at a given temperature. If the temperature increases, the air’s ability to hold moisture expands, which typically results in a decrease in RH if the moisture content remains constant.
In the context of data centres and server rooms, proper temperature and humidity control is essential. If the air is too dry (low humidity), static electricity can build up, damaging sensitive components. On the other hand, high humidity can lead to condensation, causing corrosion and potential short circuits. To prevent such issues, it’s important to monitor and control both temperature and humidity levels carefully.
Concepts like the dew point and wet bulb temperature help explain how temperature influences the moisture-holding capacity of air, but there is no simple direct conversion between temperature and humidity. Understanding this dynamic is critical for ensuring optimal conditions for the safe and efficient operation of IT equipment.
1) High Temperature and High Humidity
When high temperatures combine with high humidity, the risk of condensation inside electronic equipment increases. Condensation can form on circuit boards, power supplies, and network switches, causing short circuits and corrosion. This moisture buildup can deteriorate metal contacts, leading to connectivity issues and equipment failure. Additionally, higher temperatures accelerate chemical reactions, increasing oxidation rates and reducing the durability of sensitive components.
To mitigate these risks, many data centres rely on advanced cooling systems and dehumidification technologies. In smaller server rooms, air conditioning units that control both temperature and humidity play a key role. Proper ventilation and airflow management are also critical in both settings to prevent heat pockets from forming, reducing the risk of overheating.
2) High Temperature and Low Humidity
While high temperatures cause heat stress on IT equipment, low humidity introduces another major issue—electrostatic discharge (ESD). In dry environments, static electricity accumulates on surfaces and, when discharged, can damage sensitive electronic components like CPUs, RAM, and network switches. ESD-related failures are often unpredictable and may lead to immediate hardware malfunctions or long-term degradation.
To prevent this in data centres, humidification systems are commonly employed to maintain adequate moisture levels. In server rooms, anti-static flooring and grounding mats help further reduce the risk of static buildup. Monitoring environmental conditions regularly ensures that humidity stays within safe levels, protecting equipment from ESD-related issues.
3) Low Temperature and High Humidity
Cooler environments can sometimes hide the dangers of high humidity. When warm air containing moisture contacts colder surfaces, condensation can form, leading to rust, corrosion, and electrical shorts. This is particularly problematic in environments where temperature fluctuations are frequent, such as when servers are powered on and off.
Both data centres and server rooms address this issue by maintaining consistent temperatures and using dehumidifiers to remove excess moisture from the air. Insulation and temperature zoning strategies also help prevent condensation on critical equipment.
4) Low Temperature and Low Humidity
While low temperatures can reduce the risk of overheating, they present their own set of challenges. When humidity levels drop below 40%, static electricity buildup becomes a significant threat. This can lead to sudden ESD events that cause severe damage to microchips and integrated circuits.
To counteract this, data centres often use ultrasonic or steam humidifiers to introduce controlled moisture into the environment. Server room operators also monitor relative humidity levels in real time using IoT-based sensors to ensure conditions remain optimal.
Effect of Temperature and Humidity on Data Centre and Server Room Equipment
1) Temperature Impact
A) High Temperature (>27°C or 80°F)
Overheating & Performance Degradation: High temperatures cause thermal throttling, which reduces CPU, GPU, and memory performance. This leads to slower data processing and reduced system efficiency.
Increased Component Failure: Excess heat accelerates electromigration in semiconductor circuits, eventually causing hardware failure.
Higher Energy Consumption: Cooling systems must work harder to regulate temperatures, leading to increased power usage and operational costs.
Signal Integrity Issues: High temperatures can distort electrical signals, leading to increased latency and packet loss in communication networks.
B) Low Temperature (<15°C or 59°F)
Condensation Risk: Sudden temperature drops can cause moisture buildup inside components, leading to short circuits and corrosion.
Component Brittleness: Extremely cold temperatures make plastic and solder joints brittle, increasing the likelihood of physical damage over time.
2) Humidity Impact
A) High Humidity (>60% RH – Relative Humidity)
Condensation & Short Circuits: Excess moisture accumulates on PCBs, electrical contacts, and connectors, causing equipment malfunctions.
Corrosion & Oxidation: High humidity accelerates rust formation, particularly in metal connectors, power supplies, and circuit boards.
Mould Growth & Dust Accumulation: Damp environments attract dust particles and biological contaminants, which can clog ventilation systems and reduce cooling efficiency.
B) Low Humidity (<40% RH)
Electrostatic Discharge (ESD): Dry air increases the likelihood of static buildup, which can irreversibly damage sensitive electronic components.
Cracked Materials: Prolonged exposure to low humidity can cause plastic components, cables, and insulation materials to become brittle and crack, leading to connectivity issues and safety hazards.
Combined Effects of Temperature & Humidity
When temperature and humidity levels are not properly maintained, they create compounding risks:
| Condition | Effects on Electronics |
|---|---|
| High Temperature + High Humidity | Corrosion, condensation, overheating, hardware failure |
| High Temperature + Low Humidity | Overheating, electrostatic discharge (ESD) risks |
| Low Temperature + High Humidity | Condensation, short circuits, mould growth |
| Low Temperature + Low Humidity | Brittle materials, static buildup, potential hardware damage |
ASHRAE Thermal Guidelines for Optimising Temperature and Humidity in Data Centres
The ASHRAE Thermal Guidelines provide essential recommendations for maintaining optimal temperature and humidity in data centres to ensure the reliable operation of electronic equipment. These guidelines recommend a temperature range of 18°C (64°F) to 27°C (80°F) and relative humidity between 20% and 80%, with a maximum dew point of 15°C (59°F) to prevent condensation, which can damage sensitive equipment.
The guidelines are divided into three classifications:
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A1 (Low Temperature, Moderate Humidity): 18°C to 23°C (64°F to 73°F) temperature range, with 20% to 80% humidity. This provides the most controlled environment, ideal for critical infrastructure.
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A2 (Moderate Temperature, Moderate Humidity): 20°C to 25°C (68°F to 77°F) temperature range, with 20% to 80% humidity. A balanced setting for most standard data centres, ensuring reliability and moderate energy efficiency.
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A3 (High Temperature, Moderate Humidity): 23°C to 27°C (73°F to 80°F) temperature range, with 20% to 80% humidity. This classification helps maximise energy efficiency by allowing higher temperatures, reducing the load on cooling systems.
By following these guidelines, data centre operators can optimise energy usage, lower cooling costs, and maintain equipment reliability. While modern systems may operate outside these ranges with advanced cooling technologies, the ASHRAE guidelines offer a valuable baseline for balancing performance and efficiency. Regular updates from the ASHRAE Technical Committee (TC) 9.9 ensure these standards keep pace with new technologies and sustainability goals in the industry.
Temperature & Humidity Control Strategies
1) Cooling Systems
CRAC & CRAH Units: Computer Room Air Conditioning (CRAC) and Computer Room Air Handling (CRAH) units are vital for regulating temperature and humidity in data centres.
Liquid Cooling: Highly efficient, liquid cooling dissipates heat in high-density server racks.
Hot/Cold Aisle Containment: This technique improves cooling efficiency and prevents thermal hotspots by separating hot and cold airflow.
2) Humidity Control
Dehumidifiers: Used in high-humidity environments to prevent condensation and corrosion.
Humidifiers: Essential in dry environments to prevent electrostatic discharge and maintain safe moisture levels.
3) Environmental Monitoring
IoT-Based Sensors: These sensors track temperature and humidity fluctuations in real time, enabling proactive adjustments.
AI-Powered Predictive Analytics: Utilises machine learning to predict environmental risks and optimises cooling and humidity levels automatically.
Conclusion
In summary, maintaining optimal temperature and humidity levels in data centres and server rooms is crucial for protecting IT infrastructure. ASHRAE recommends a temperature range of 18°C to 27°C (64°F to 80°F) and humidity levels between 40% and 60%. Proper control of these factors prevents overheating, condensation, corrosion, and static electricity, which can damage equipment. Implementing advanced cooling, humidification, and real-time monitoring systems helps maintain these ideal conditions. By following these guidelines, organisations can enhance system reliability, improve energy efficiency, and extend the lifespan of their hardware.
