What are the four main items regarding retrocommissioning during the implementation phase?

• A. Perform TAB on existing; FPTing; Review O&M staff training; Cx final report
• B. Cx final report; Develop Cx scope; Owner selects CxA; Prepare Cx plan
• C. Conduct site survey; Review energy models; Commissioning of new systems; Document lessons learned
• D. Perform TAB on existing; Review O&M staff training; Training O&M staff; Cx final report

Answer: (A)

Retrocommissioning during implementation focuses on verifying and optimizing the existing building systems to achieve targeted performance. The four main items fit this phase because they directly test and finalize how the current systems operate after adjustments, and ensure the gains are sustained.

Perform TAB on existing establishes that the current air and water distribution and control systems are properly balanced after retrofits, which is essential to confirm the system can deliver intended performance without over- or under-pressurization or flow issues.

Functional Performance Testing checks that the systems operate correctly under real operating conditions and meet the expected performance criteria once adjustments are made. This step verifies that the changes actually produce the desired results, not just theoretical improvements.

Review O&M staff training ensures the personnel who operate and maintain the building understand the new or adjusted controls and sequences, so the performance gains are maintained over time.

Cx final report documents what was done, the results, any issues found, and actions taken, providing a record for ongoing operations and future retrocommissioning work.

Other options mix planning activities or tasks relevant to new construction rather than retrocommissioning of existing systems, or include items that belong in different phases, which is why they’re not the best fit for the implementation phase.