<P> Note: The Uptime Institute also classifies the Tiers for each of the three phases of a data center, its design documents, the constructed facility and its ongoing operational sustainability . </P> <P> A data center can occupy one room of a building, one or more floors, or an entire building . Most of the equipment is often in the form of servers mounted in 19 inch rack cabinets, which are usually placed in single rows forming corridors (so - called aisles) between them . This allows people access to the front and rear of each cabinet . Servers differ greatly in size from 1U servers to large freestanding storage silos which occupy many square feet of floor space . Some equipment such as mainframe computers and storage devices are often as big as the racks themselves, and are placed alongside them . Very large data centers may use shipping containers packed with 1,000 or more servers each; when repairs or upgrades are needed, whole containers are replaced (rather than repairing individual servers). </P> <P> Local building codes may govern the minimum ceiling heights . </P> <P> Design programming, also known as architectural programming, is the process of researching and making decisions to identify the scope of a design project . Other than the architecture of the building itself there are three elements to design programming for data centers: facility topology design (space planning), engineering infrastructure design (mechanical systems such as cooling and electrical systems including power) and technology infrastructure design (cable plant). Each will be influenced by performance assessments and modelling to identify gaps pertaining to the owner's performance wishes of the facility over time . </P>

Which process or function is responsible for management of the data centre facility