Construction-Phase Commissioning Activities and Functional Performance Testing
Construction-phase sequence
Construction-phase Cx includes: Cx kickoff and coordination, review of submittals and O&M data, witnessing and documenting pre-functional checklists (PFCs), developing and executing functional performance tests (FPT), tracking deficiencies, and verifying corrections. Pre-functional checks confirm installation and static conditions before functional testing. Trap: confusing pre-functional (installation/startup checks) with functional testing (dynamic, system-level performance).
Functional performance testing
FPT verifies that systems and assemblies perform interactively according to the OPR and BOD. Tests should be written before construction ends, based on design intent and sequences. Good FPTs include prerequisites, step-by-step procedures, expected results, acceptance criteria, and documentation. Test the whole system, including controls, safeties, and interlocks - not just individual components.
Deficiencies and documentation
Every failure is logged as a deficiency with owner, status, and resolution. The CxA verifies retesting after correction. Documentation includes test records, issues log, and progress reports.
Rule of thumb
Test to the design intent, not to what the equipment happens to do. If the sequence says a valve modulates to maintain setpoint, the test must demonstrate that behavior, not merely that the valve moves.
Worked example
A chiller plant FPT requires verifying lead/lag rotation and failure response. The CxA scripts the steps, expected responses, and acceptance criteria, then witnesses the test and logs a deficiency when lag chiller fails to start on lead failure.