The physical environment of a data center is rigorously controlled. Air conditioning is used to control the temperature and humidity in the data center. ASHRAE’s “Thermal Guidelines for Data Processing Environments,recommends a temperature range of 16–24 °C (61–75 °F) and humidity range of 40–55% with a maximum dew point of 15 °C as optimal for data center conditions.The temperature in a data center will naturally rise because the electrical power used heats the air. Unless the heat is removed, the ambient temperature will rise, resulting in electronic equipment malfunction. By controlling the air temperature, the server components at the board level are kept within the manufacturer’s specified temperature/humidity range. Air conditioning systems help control humidity by cooling the return space air below the dew point. Too much humidity, and water may begin to condense on internal components. In case of a dry atmosphere, ancillary humidification systems may add water vapor if the humidity is too low, which can result in static electricity discharge problems which may damage components. Subterranean data centers may keep computer equipment cool while expending less energy than conventional designs.
Modern data centers try to use economizer cooling, where they use outside air to keep the data center cool. Many data centers now cool all of the servers using outside air. They do not use chillers/air conditioners, which creates potential energy savings in the millions.
Telcordia GR-2930, NEBS: Raised Floor Generic Requirements for Network and Data Centers, presents generic engineering requirements for raised floors that fall within the strict NEBS guidelines.
There are many types of commercially available floors that offer a wide range of structural strength and loading capabilities, depending on component construction and the materials used. The general types of raised floors include stringerless, stringered, and structural platforms, all of which are discussed in detail in GR-2930 and summarized below.
- Stringerless Raised Floors – One non-earthquake type of raised floor generally consists of an array of pedestals that provide the necessary height for routing cables and also serve to support each corner of the floor panels. With this type of floor, there may or may not be provisioning to mechanically fasten the floor panels to the pedestals. This stringerless type of system (having no mechanical attachments between the pedestal heads) provides maximum accessibility to the space under the floor. However, stringerless floors are significantly weaker than stringered raised floors in supporting lateral loads and are not recommended.
- Stringered Raised Floors – This type of raised floor generally consists of a vertical array of steel pedestal assemblies (each assembly is made up of a steel base plate, tubular upright, and a head) uniformly spaced on two-foot centers and mechanically fastened to the concrete floor. The steel pedestal head has a stud that is inserted into the pedestal upright and the overall height is adjustable with a leveling nut on the welded stud of the pedestal head.
- Structural Platforms – One type of structural platform consists of members constructed of steel angles or channels that are welded or bolted together to form an integrated platform for supporting equipment. This design permits equipment to be fastened directly to the platform without the need for toggle bars or supplemental bracing. Structural platforms may or may not contain panels or stringers.
