In industry terms, a 19-inch rack is a frame or enclosure that is used to mount multiple equipment units. Each rack module has a front panel that is 19 inches or 482.6 mm wide. This horizontal measurement includes the edges on the side of the rack. IT equipment that is manufactured with dimensions to fit in a rack will often be called rack-mount or rack-mountable. The terms rack-mounted system, rack-mount chassis, server rack and sub-rack are commonly used.
Standard 19″ Racks in the Data Centre
Data centres and server rooms have computing equipment located in standard 19″ racks. These racks can be in two or four post formats. The height is also standardised in multiples of 44.50 mm or 1.752 inches. This height measurement is also known as one rack unit or a “U.” The IT industry considers a standard IT rack structure as 42U tall. Using standard racks, networking hardware or AV equipment can be configured efficiently without requiring floor space or shelf installations. Racks serve a range of placement demands, securing everything from basic equipment to dense computing applications. Racks can also assist with data centre power management.
Rack Unit Dimensions
The measurement of each rack unit is 1.75 inches wide. Standardised rank units are designed to assist administrators in buying, mounting and uninstalling servers, computers or other devices. Data server racks and cabinets may be chosen based on functionality, including cooling and cabling management options. Cabinets and racks vary by U height, width, depth, front door style, security, and other features.
19” Inch rack/cabinets generally are divided into the following sections:-
Range from 4u to 8u in height and have a shallow depth of approximately 275mm. These cabinets are used in small office/classroom applications to house 1 or 2 patch panels and maybe a small switch if required. These small and compact cabinets require limited space.
Wall Mount Cabinets
Range from 6u to 21u in height and are generally available in depths of 390mm, 450mm, and 600mm. These cabinets are also used in small office/classroom/retail applications but due to the larger size range available, can be used to house communications equipment for a small office where floor space is unavailable or security (positioned out of reach) of location is an issue.
Floor Standing Data cabinets
Range from 12u to 47u in height and are generally available in depths of 600mm, and 800mm. These cabinets are used in applications where a large number of passive devices are required. RJ45 patch panels and voice panels are the most common products installed in these cabinets. These cabinets are optimised for cabling, therefore they have additional cable entry points and cable management features but have poor ventilation so are not suitable for housing active equipment such as switches and servers.
Floor Standing Server Cabinets
Range from 12u to 47u in height and are generally available in depths of 1000mm, and 1200mm. These cabinets are used to house active equipment such as switches, servers, UPS’s, and telephone systems. In larger applications the passive equipment such as patch panels would be housed in a data cabinet whilst all the active equipment would be housed in a server cabinet which offers greater depths, better ventilation, and higher load capacity. Smaller companies and applications would house both passive and active equipment in a floor-standing server cabinet.