Making Commissioning clear


What is it?


Recommissioning is another type of commissioning that occurs when a building that has already been commissioned undergoes another commissioning process. Recommissioning is similar to retrocommissioning, although it is less expensive since some of the difficult data collection and documentation tasks were accomplished during the original project and need only to be revalidated. Recommissioning typically begins with a review of the Owner's Operating Requirements to
determine if there have been any changes.



The decision to recommission may be triggered by a change in building use or ownership, the onset of operational problems, or some other need. Ideally, a plan
for recommissioning is established as part of a new building's original commissioning process or an existing building's retrocommissioning process.

Recommissioning is one of the steps that can be taken to ensure that retrocommissioning, other efficiency measures, and their associated benefits last.

Positive answers to two or more of the following questions indicates that it may be time to recommission:
• Is there an unjustified increase in energy use? Is energy use more than 10% higher than previous years?
• Have comfort complaints increased compared to previous months or years?
• Has nighttime energy use increased?
• Is building staff aware of problems but without the time or in-house expertise to fix them?
• Has control programming been modified or overridden to provide a quick fix to a problem?
• Are there frequent equipment or component failures?
• Have there been significant tenant improvement projects (build-outs)?
• Has it been five years or more since the previous recommissioning process?

• Have any major energy consuming systems or controls been replaced recently?




Recommissioning typically begins with a review of the Owner's Operating Requirements to determine if there have been any changes. When changes have occurred, systems are reviewed to determine if corresponding changes in equipment or operations are necessary.

• Systems are inspected and any issues are recorded in a Recommissioning Master List of Findings.

• Functional performance tests and trend logs are used to determine if the systems are still operating as intended.
• Minor system improvements may be implemented during recommissioning, while others may require more significant design, scheduling and budgeting.

• The building documentation is also reviewed to determine if updates or trainings are required.

• The Owner's Operating Requirements document is updated to reflect any changes in building systems and functions.


Getting Started


• Please see "Getting Started" within Existing Building Commissioning for details.