Systems that control the environment in a building change with time and use, and must be rebalanced accordingly. The designer must consider initial and supplementary testing and balancing requirements for commissioning. Complete and accurate operating and maintenance instructions that include intent of design and how to test, adjust, and balance the building systems are essential. Building operating personnel must be well trained, or qualified operating service organizations must be employed to ensure optimum comfort, proper process operations, and economical operation. This chapter does not suggest which groups or individuals should perform a complete testing, adjusting, and balancing procedure. However, the procedure must produce repeatable results that meet the design intent and the owner’s requirements. Overall, one source must be responsible for testing, adjusting, and balancing all systems. As part of this responsibility, the testing organization should check all equipment under field conditions to ensure compliance. Terminology General Criteria Air Volumetric Measurement Methods Instruments Air Testing, Adjusting, and Balancing Balancing Hydronic Systems Hydronic Balancing Methods Fluid Flow Measurement Balancing Steam Distribution Systems Balancing Cooling Towers Verification of Controls Operation Thermal Performance Verification Outdoor Air Ventilation Verification Temperature Control Verification Testing for Sound and Vibration Field Survey for Energy Audit TAB Reports