Commissioning is the application of a simple principle: prevention costs less than late correction. Through a series of interventions, checks and processes during design, construction and occupancy, commissioning controls the quality of the work and the smooth transfer of the works to the operating personnel and the customer. This ensures that the building or system meets established performance, quality and operating requirements. Because it requires experience in maintenance and operation, in-depth knowledge of control systems and outstanding organizational skills, commissioning is often separated from the design mandate and entrusted to a team of specialized, certified professionals.