Commissioning is a quality control process performed by a team with representatives from all the major entities involved in a construction or upgrade project. The process is led by the commissioning agent, but many, if not most, of the activities are performed by the other team members. For the process to work correctly, it is imperative that each participant understand his or her specific role and execute the duties and responsibilities associated with their role and purview.
Formal, full life-cycle commissioning begins during the initial programming phase of the project prior to developing the actual engineering and design documents. It then continues through the engineering and design phase, construction phase, startup and acceptance testing, and extends into the initial operation of the facility or infrastructure and includes delivering comprehensive site as-built and record documents as well as operations staff training.