Standards for Data Center Temperature and Humidity

Every system administrator knows how important it is to maintain certain environmental conditions in server rooms since computing hardware is vulnerable to changes in the atmosphere. The Ashrae standard was developed to systematize this scope of indicators. This is a set of rules adopted for different types of premises to ensure optimal ventilation conditions and improve the quality of building use. The document determines the optimal data center temperature and humidity standards.

The rise of the document goes back to 1895 when the Association of American Engineers started to develop norms for heating and ventilation in all sorts of buildings. The society dealt with the development of guidelines for air conditioning, refrigeration, and heating. In 2004, the association created a core set of guidelines for heat allocation in data centers. The second and third editions were adjusted to modern hardware and re-published. Each time, new information was added to the document. Amendments were related to the classes of servers and other computing hardware that could operate at ever higher allowable levels of environmental indicators. Nowadays, the standard has a separate chapter devoted to the regulation of the environment in data centers.

Classes of ASHRAE Hardware

According to the ASHRAE standards, they distinguish between four main classes of equipment:

• Class A1 equipment operates in the temperature range from 59°F to 90°F with a dew point of humidity ranging from 20% up to the maximum of maximum 80%;
• Class A2 hardware functions under the operating temperatures of 50-95°F with a relative humidity of 20% to 80%;
• Class A3 devices work in the temperature range from 41°F to 104°F with a dew point of relative humidity of 8% to 85%;
• Class A4 apparatus operates in the temperature range from 41°F to 113°F with a relative humidity of 8% to 90%.

Most of the devices in modern data centers fall into Class A1 or A2, although an overwhelming number of hardware manufacturers, such as Dell, are involved in the production of hardware of Class A3 or A4. Manufacturers are more likely to offer a wider range of A3 and A4 devices due to a rich assortment of data center designs.

Statistical studies show that in the case of properly designed servers, the failure rate does not increase when operating at high temperatures, and reliability does not decrease. But, keep in mind that backward compatibility of the ASHRAE guidelines with legacy hardware is not possible. That is, a new Class A3 or A4 server will perform just fine in a more complex environment, but deteriorated Class A1 hardware will not function reliably in more challenging environments. Besides, ASHRAE guidelines allow devices to operate under more difficult operating conditions for short periods of time, making it easier to maintain system continuity in the event of a cooling problem.

Importance of Maintaining Optimal Environment in DCs

The need to regulate and create particular environmental conditions is determined by apparatus vulnerability. Computing devices require satisfying certain environmental parameters to guarantee smooth functioning and reliable datum storage and processing.

With proper implementation of standards through careful site design and system deployment, the data center’s reliance on traditional mechanical cooling methods is reduced. This reduces cooling costs and increases equipment reliability. Thus, it is vital to maintain the ideal temperature for data center and monitor the level of humidity on the premises. Every published standard or collection of ASHRAE recommendations has gone through a rigorous peer review process. Particular efforts have been made to assess the views of parties interested in or referred to in the proposed standards. The result of the work is the finished product, obtained on the basis of the consent of all interested parties. The agreement of the parties to these standards is voluntary since only the regulatory body has the authority to insist on the adoption of a particular standard as mandatory. However, ASHRAE’s standardization process itself has proved so authoritative that many other standards have been developed from it.