Cooling Strategies For IT Wiring Closets And Small Rooms

By Neil Rasmussen, senior VP of innovation, Schneider Electric, and Brian Standley, product line manager, APC

The design of data centers and large computer rooms always includes a cooling system. Yet many IT devices are located in distributed spaces outside of the computer room in closets, branch offices, and other locations that were never designed with provisions for cooling IT equipment. The power density of IT equipment has increased over time and the result is that distributed IT equipment such as VoIP routers, switches or servers often overheat or fail prematurely due to inadequate cooling.

The typical approach to this problem is to ignore it, deploy equipment, and then respond with corrective action if and when equipment overheats and/or fails. More and more users are finding this approach unsatisfactory and demand a more proactive approach to ensuring the availability of distributed IT equipment. The purpose of this paper is to outline the basic principles of cooling small, distributed IT environments and to provide guidance for the effective specification and design of supporting cooling systems.

To properly specify the appropriate cooling solution for a wiring closet, the temperature at which that closet should operate must first be specified. IT equipment vendors usually provide a maximum temperature under which their devices are designed to operate. For active IT equipment typically found in a wiring closet, this temperature is usually 104°F (40°C). This is the maximum temperature at which the vendor is able to guarantee performance and reliability for the stated warranty period. It is important to understand that although the maximum published operating temperature is acceptable per the manufacturer, operating at that temperature will not generally provide the same level of availability or longevity as operating at lower temperatures. Because of this, some IT equipment vendors also publish recommended operating temperatures for their equipment in addition to the maximum allowed. Typical recommended operating temperatures from IT equipment vendors are between 70°F (21°C) and 75°F (24°C).