Today, the raised floor is still an important element in many new data centers. But why? What is it for, what does it do? Below are a few thoughts on the subject of raised floors.
To loosely quote DIN EN 50600 (also see "Data centre standard DIN EN 50600 (VDE 0801-600) in brief"), the raised floor is a system consisting of completely removable and exchangeable floor grills fitted onto adjustable base frames, which are interconnected by beams. Its purpose is to make the space under the floor available for facility services.
Now as ever, precision air conditioning units (CRAC or CRAH) are still the first choice for air conditioning data centers, even now in the age of in-row cooling, rack cooling and air handling units. This article does not go into the reasons for this. Instead, it deals with the raised floor which, in conjunction with precision air conditioning units, ensures maximum reliability and efficiency.
In the past, the raised floor concealed "facility services" such as power cables, data cables and piping, and the cold air had to painstakingly find its way through these to the air outlets. A good deal has changed since then. It is now common knowledge that the primary aim of the raised floor is to convey cold air to the servers, and so wiring is mostly routed above the racks. In addition, these days the height of the raised floor is planned to ensure that the air in this supply air duct has sufficient space to reach its destination without major losses or resistance.
It is vital that a raised floor is leak-proof if it is to be used for air distribution. Care must be taken to ensure that the cold air only leaves the raised floor in the direction of the servers where planned and where most effective. Leaks in cable glands, beneath racks or at wall connections must be meticulously sealed. Raised floor grills that are removed for maintenance purposes are a hindrance to air distribution. This should be reduced to the necessary minimum.
