Ashrae Temperature Criterion
ASHRAE, as the U.S. Mechanical Engineering Association, also operates a separate unit (ASHRAE TC 9.9) on Data Centers. This Unit; It works with IT device manufacturers as well as companies that research, provide and manufacture cooling systems to set standards that will guarantee the expected business continuity.
The table below shows the standard requirements announced in 2011 and still valid. There are a total of 6 classes in the table, 4 of which are A. The table provides criteria in 2 categories for Class A.
The first is the recommended temperature and humidity criteria that should be followed for each class in the usual situation. It is recommended that the air at the device inlet be between 18 – 27 °C and 60% relative humidity, corresponding to the condensing temperature of 5.5 °C.
The second category for Class A is defined separately for each class as “allowable”. If there is a short-term failure or inconsistency in the cooling system, there is a permissible range. This “permissible” range can also be used in a controlled manner to increase energy efficiency.
It is estimated that parameters corresponding to the expected life of the server will also appear in server management features in the near future. As it is known, active use of the server for more than 3-5 years becomes uneconomical due to the inadequacy of the technology on it and its renewal becomes necessary. In that case, using the permissible range in a way that will increase energy efficiency based on the limited lifespan is also addressed in this directive.
In this range, the temperature band can be drawn between 15°C and 32°C, and the relative humidity band can be drawn between 20% and 80%. The important issue here is the safe operating range of the IT devices used. If the “permissible” range is not supported by one or more devices, working in this range is detrimental in terms of business continuity.
Ashree Temperature Criterion
A1 class is taken as a criterion for corporate data centers. The correct classes in A4 are; It is taken as a criterion in data centers that use a large number of servers and provide widespread services such as virtualized services or “big data”. The selection is made by taking into account the total cost of ownership of the data center, including its IT inventory.
In the table, not only temperature and relative humidity criteria, but also maximum condensation temperature, altitude, dynamic temperature change and storage conditions are evaluated as criteria.