Environmental Standards for IT Equipment

ASHRAE

The American Society of Heating, Refrigeration and Air-Conditioning Engineers Technical Committee 9.9 represents IT manufacturers. The publication 2011 Thermal Guidelines for Data Processing Environments – Expanded Data Center Classes and Usage Guidance provides information to engineers and end users to analyse the implications of operating for short periods outside of the recommended envelope.  This also addresses a misinterpretation of the 2008 publication:

“some still felt the recommended envelope was mandatory, even though that was never the intent”

The end user can use this to analyse the Total Cost of Ownership with reference to reliability. The diagram below shows the performance of EcoCooling evaporative coolers compared to the standards.

Temperature, humidity and contamination must all be considered when designing a cooling system for a server room or data centre.  The diagram below shows recognised standards, the typical manufacturer environmental specification and the performance expected from an EcoCooling CREC in a temperate climate as found in Northern Europe.

What is the temperature range?

Most modern servers are designed to operate at between 10C and 35C.  Care should be taken when operating over 25C as most server ventilation fans are designed to increase in speed to accommodate the higher air intake temperatures.  This leads to increased energy use of the fan and potential noise problems.
For more information on temperature control click here .

What is the humidity range?

Whilst Relative Humidity (RH) is the most recognised measurement of humidity, modern standards also refer to the Dew Point which is a measure of Specific Humidity (SH).  Historically the key issues associated with humidity are static electricity and the effects of the content and rate of change of change of moisture in the air on paper and magnetic tape systems.  Modern equipment with correctly earthed racks, components and raised floors along with good maintenance procedures has rendered close control of humidity redundant.  There is little data to support the business case for the use of humidification in the prevention of equipment failure.  The majority of the telecoms industry uses no humidification. For more information on humidity control click here

What about dust and external contamination?

Modern IT equipment has closed drives and sealed bearings.  The Intel Proof of Concept Study in a high density data centre using fresh air with no filtration showed no significant increase in failure rate despite the servers being completely covered in dust.  [http://communities.intel.com/docs/DOC-1840].  The cooling pads and insect screens fitted to an EcoCooling CREC system result in no visible dust. EcoCooling can now provide filtration to G4 standards should this be required. For more information on filtration click here.

Care must be shown if air intakes can bring in carbon deposits such as those found in engine exhaust fumes, particularly diesel engines, and smoke from burning carbon fuels.

Some examples of specified operating conditions.


Manufacturer

Model

Temp C

Humidity

IBM

eServer xSeries 225

Min 10° Max 30°

8 - 80%

Dell

PowerEdge 4400

Min 10° Max 35°

8% to 80% non-condensing

Cisco

MXE 300

Min 10° Max 35°

10% to 90% non-condensing

HP

server rx4610

Min 5° Max 35°

20% to 80% non-condensing

Useful links about new approaches to cooling of data centres and server rooms.

Intel’s proof of concept of fresh air cooling in New Mexico.
Note the following:

  • Very little control compared with EcoCooling
  • No significant filtration compared with EcoCooling
  • No increased failure!
  • Recognition of changing standards of environmental standards for modern equipment.
  • Hot and cold aisles being important

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