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Additional considerations Projects with phased construction and phased Cx testing should consider multiple Cx readiness site visits that align with each phase of the construction efforts.

Functional Performance Tests — Execution

The CxP must witness functional performance testing executed by the contractors and subcontractors. Perform testing when all system components are installed, energized, programmed, balanced, and checked for functionality.

FPT SAMPLING A sampling strategy is acceptable for functional testing of projects with a large number of similar system types, like an office with multiple VAV boxes or a multi-family residential building with individual heat pumps for each tenant.

An acceptable sampling rate is typically 10%. The CxP should consider the testing procedure’s failure rate when using a sampling rate. If multiple failures occur for the same equipment or system type, determine if there is a systemic issue.

Additional example — sampling rate and failure rate A hotel has 200 fan coil units. The owner and CxP agree to a 10% sampling strategy. During testing, the CxP tests 20 fan coil units. If 10 of the 20 tests fail, conduct additional testing. Failures of that magnitude would cause more concern.

SEASONAL OR DEFERRED TESTING When necessary, the CxP can use seasonal or deferred testing. For example, if the initial FPT effort occurs in the summer, tests for heating mode can occur during colder months. Once testing is complete, the CxP is responsible for amending the final report and other documents.

Meetings

During the construction phase, the CxP participates in 50% and 100% milestone meetings to discuss the commissioning findings and work toward resolving identified issues.

Final Cx Report

The CxP is the primary one responsible for authoring the final Cx report. The final report should include, at minimum, an executive summary of the Cx process and the results of the project’s testing efforts, an updated issues and resolution log that identifies items that are closed and

U.S. Green Building Council LEED v5 Reference Guide for Building Design and Construction, April 2025 Launch Edition 235