The commissioning professional has a very persuasive position as a consultant hired by the owner working toward verifying that all the systems of a building work according to the construction document requirements. If the commissioning professional maintains careful documentation and keeps the design engineer informed of design issues as they arise, the commissioning process will retain a clear engineer of record. Responsibility also lies with the design engineer to assist the commissioning professional with timely clarifications and modifications to commissioned systems.
As a design engineer, who has increasingly been involved with the commissioning side of projects, I often fight the urge to redesign a system as the commissioning process is underway. I know I am not the only one fighting this urge. It is, after all, easier to pick apart an existing design than it is to design the perfect system from scratch. Instead, focus needs to be shifted to asking questions of the design engineer when there are discrepancies. If the questions are phrased carefully, they will save the design engineer time researching the issue, the sequence of operation will be clarified, the control contractor will be able to program effectively, and the owner will receive the expected system operation. Just as importantly, the design engineer will remain responsible for the final system design.