Describe the organizational structure for recommissioning and retrocommissioning in existing buildings.

• A. Owner -> Owner's O&M Staff -> CxA -> Subs
• B. Owner -> CxA -> Owner's O&M Staff -> Subs
• C. Owner's O&M Staff -> Owner -> CxA -> Subs
• D. Subs -> CxA -> Owner -> Owner's O&M Staff

Answer: (A)

The main idea is to put the flow of information and responsibility in the right order so the commissioning effort reflects how the building actually operates and who has the authority to move things forward. In recommissioning or retrocommissioning of existing buildings, the owner should start by naming a representative and bringing in the building’s O&M staff. These operations people know how systems behave in day-to-day use, what performance issues exist, and what constraints and goals matter for the building’s real operation. Capturing that context up front ensures the project basis is accurate and aligned with current needs.

With that foundation, the commissioning authority takes the lead on planning and verification. The CxA develops the commissioning plan, creates test procedures, and documents performance against the agreed goals. The CxA acts as an independent coordinator, ensuring that the work stays focused on achieving the desired outcomes and that any gaps or deficiencies are clearly identified.

The actual work to meet the goals—tuning, repairs, adjustments—gets carried out by subcontractors, under the guidance of the CxA and with input from the owner’s O&M staff. This keeps the execution grounded in the building’s realities while ensuring the owner and their operations team have ongoing visibility and control over changes.

So, the natural sequence that best supports effective recommissioning and retrocommissioning is the owner, followed by the owner’s O&M staff, then the commissioning authority, and finally the subcontractors.