Such was the case with Oberlin College in Oberlin, Ohio, which recently conducted its first re-commissioning project on campus, including a nearly yearlong investigation, implementation and remediation process at their 229,000-square-foot Science Center. As the commissioning authority on the project, Baltimore-based RMF Engineering determined that holistic views of building-level and district-utility-level energy-conservation measures (ECMs) were key to meeting campus energy goals. Coordinating discussions between the staff responsible for the buildings and district energy systems while conducting the re-commissioning work with a concurrent energy neutrality project helped to ensure that the overall energy savings goal was achieved.
Existing building commissioning, as defined by the AABC Commissioning Group, Washington, D.C., may be classified as either re-commissioning or retro-commissioning when the re-commissioning is conducted on a building whose HVAC systems have been commissioned previously during either construction or at a point in time after initial occupancy. Retro-commissioning is the term used when commissioning is conducted on a building whose systems have never been commissioned.
The Science Center underwent a construction renovation project in 2000 that fused three separate buildings of different maturities under a single roof, along with a new chemistry wing. This presented unique challenges to the re-commissioning and project teams. A critical component to any re-commissioning project is conducting a thorough review of any existing documents, including as-built drawings, commissioning reports, maintenance records, etc. Because of the nature of the 2000 renovation, there was not a single set of documents that allowed for review of the HVAC systems. This meant that four separate sets of drawings ranging from original design documents to renovation plans from 1993 until 2000 had to be reviewed and interpreted.
The fact that there were multiple utility-service entrances to the building and an undetermined electrical feed from one wing of the building out to student housing presented additional complications. A vital component to the success of this re-commissioning project was the assurance that campus energy goals were being met. This meant there was a need for more utility metering than was initially anticipated. Upon this discovery, the project team worked together with a concurrent campus metering project to budget for and identify locations for 12 new utility meters in the Science Center.
One of the largest hurdles on a project such as this is determining how to functionally test systems while the building is fully occupied. An essential component to the functional testing is to ensure proper equipment failure sequences while maintaining proper laboratory pressurization. Many of the tasks RMF Engineering was asked to perform needed to be carried out during occupied hours while laboratories were being used for research and education.
The project team determined the as-built drawings on hand were an adequate guide for mechanical systems but were certainly not perfect. This is standard feedback; however, it drove a need for an upfront as-built verification process. All HVAC ductwork had to be followed out and new air-handling unit (AHU) zoning plans needed to be created so equipment shutdown effects could be understood. Through this process, the project team learned that its understanding of the areas of the older, existing wings where the AHUs and exhaust systems were thought to have served a purpose were incorrect. This reinforced the need to generate these AHU zoning plans, which is a process RMF Engineering is now rolling out to all of its re-commissioning and retro-commissioning projects.
As with any laboratory re-commissioning or retro-commissioning project, extensive site access must be scheduled. Weekly site access and room-by-room scheduling needed to be conducted to ensure no functional testing would impact student and occupant safety or any ongoing research. Much of the work on the centralized systems—such as the AHUs, chillers, boilers, etc.—had to be conducted during off-hours, weekends, school closings and holidays.