The dimensions of data center server racks are standardized but offer various options to accommodate different equipment needs. The standard rack height is measured in rack units (U), with each U equaling 1.75 inches (44.45 mm). The most common standard rack height is 42U, measuring 73.5 inches (1866.90 mm) tall, although 48U racks are also used in some data center rack designs.
The 19 inch rack
The standard server rack width for mounting equipment is 19 inches, known as the 19-inch rack standard. The exterior rack width typically measures 24 inches (600 mm). Wider options of 29.5 inches (750 mm), sometimes called the 30-inch width, and 31.5 inches (800 mm) are available for specific thermal requirements or equipment space needs.
Server rack depth varies more significantly, ranging from 27 inches (shallow) to 48 inches (1215 mm), with some racks extending up to 59 inches (1500 mm) deep to accommodate PDUs, cable management, and airflow management. Common standard rack depths include 31 inches (moderately deep), 36-37 inches (average), and 42 inches (deep). Choosing the right rack depth is crucial for cooling efficiency in the server room.
The 42U standard rack height, 19-inch mounting width, and 36-42 inch standard server rack depth configuration is a prevalent standard. Deeper racks (42-48 inches) are becoming increasingly popular to accommodate larger servers and other rackmount dimensions.
Buy a rack that has room for future expansion
When selecting data center rack size and server rack measurements, it is crucial to consider current equipment specifications, available raised floor space, weight capacity needs, and potential future expansion requirements. This ensures optimal utilization of the data center infrastructure, whether using open-frame racks or enclosed server cabinet sizes. Pay attention to the internal dimensions and U-space to properly house equipment. Cable trunking and arranging racks in hot aisle/cold aisle layouts can improve airflow. Half-racks with a 24-inch exterior width are also an option for smaller network rack sizes. Adjustable mounting rails provide flexibility. By evaluating these factors, you can determine the ideal standard server rack size for your needs.