Data Centre Cooling - Contamination
When fresh air is used in a data centre there can be a risk of either particulate or gaseous contamination. The quality of the air in the locality of the data centre can affect the feasibility of the use of fresh air. There are, however, many installations in the UK which have been operating for more than 3 years without significant filtration, experiencing no elevated levels of failure, but do show visible signs of dust and contamination. It is now normal to fit filtration to EU4/G4 standards.
A recently completed project at Cambridge University uses CRECs to supply air to a ceiling void which is then filtered through G4 grade cartridges. This allows a large number of filter elements to be installed with minimum cost and space requirements. It also retains the use of low energy axial fans.
Should the local air contain a level of particulates requiring higher levels of filtration or if gaseous contamination is at a level which could result in corrosion then it is unlikely the use of a fresh air system is appropriate.