Commissioning professionals, myself included, have always advocated the delay of systems acceptance by and turnover to the owner until the commissioning process is complete. In this sense, “complete” means the systems pass their functional performance tests and the owner’s operations staff has been properly trained.
There is one situation, and it is not simply theoretical, where this may not be the best approach for the owner. If a project is very poorly managed, uncoordinated, behind schedule, and starting to be used by occupants, it may be time to throw in the towel and turn the systems over to the owner’s operators for final system setup, tweaking, and scheduling. Without proper training of the operators by the contractors (which is to be assumed with such a scary project scenario), a fully engaged commissioning professional is in the best position to facilitate this approach to a successful and timely conclusion.