The Department of the Prime Minister and Cabinet offices at 1 National Circuit, Barton ACT, engaged PSG Holdings to carry out a major service upgrade to their Main Computer Room (MCR), which houses their highly secure ICT infrastructure. The Main Computer Room had to remain operational for the duration of the project. This involved meticulous staging of the removal of critical infrastructure that had reached end of life and the installation of the new critical infrastructure to support the departments new requirements. The construction of this project was critically staged and sequenced to ensure that the space remained operational for the duration of the project and allowed PM&C personnel to conduct works within the racks. Works were completed without impact to the critical operations of the facility.