A data center comprises a plurality of sections (15a-15h) assembled together to define a unitary structure (10) such that there exists at least one personnel area that spans at least two sections; wherein the sections comprise a first section with which there is associated a first service—carrying chassis (40, 50, 60, 70) and a second section with which there is associated a second service—carrying chassis 40, 50, 60, 70), each of the first and second service—carrying chassis comprising a frame (41, 51, 61, 71) onto which is mounted components of at least two different services (42-44, 46); the first and second chassis are connected to each other by means of a junction (47) between the first and second chassis; and the first and second sections each include a ceiling (22) and the first service carrying chassis is mounted on the ceiling of the first section and the second service carrying chassis is mounted on the ceiling of the second section.