ABSTRACT
Retro-commissioning (RCx) is the commissioning process in existing buildings. It seeks to improve the system performance together with indoor environmental quality. In all, retro-commissioning fine tunes and/or upgrades a building’s operations and maintenance (O&M) procedures to enhance overall building performance. Retro-commissioning will help to keep the building operating at optimal levels. The timing of a retro-commissioning effort will vary depending on the timing of changes in the facility’s use, the quality and schedule of preventive maintenance activities, and the frequency of operational problems. Commissioning work always requires the drawings and documentation of current design and component selections. Retro-commissioning is executed based on the owner’s expectations of the future performance of a building. It is also possible that requirements have increased since the initial commissioning phase in terms of indoor air quality or energy use of the system. Commissioning process and planning follow mainly the same steps as during the initial commissioning.
