This article explains what building commissioning is, what a building commissioning agent (CxA) is, and why building commissioning is important to green buildings, such as those certified to LEED standards.
What is Building Commissioning?
Building commissioning is the professional practice of ensuring that buildings are successfully delivered and operate according to the owner’s project requirements (OPR) and basis of design (BOD) specifications.
Commissioning is synonymous with smart property management in any building… However, in buildings that are green or designed with “smart” building technologies, investment in commissioning is critical to ensuring that high performance building strategies are effective in practice, not just in theory.
“…a quality-oriented process for achieving, verifying, and documenting that the performance of facilities, systems, and assemblies meets defined objectives and criteria”.
Why is Building Commissioning Important?
Just as it’s important for a Formula 1 race car to be tested before a race, it is important for a green building to be commissioned before operation to confirm (or deny) its performance is high and according to the owner’s specifications.
Indeed, owners should insist on technical commissioning in all of their buildings to ensure investment success. For building owners considering LEED, the good news is that LEED requires commissioning to achieve certification.
Commissioning starts with documentation driven by the owner’s interests and performance specifications. The owner’s project requirements (OPR) and basis of design (BOD) are two documents that are required in the commissioning process and used by the commissioning agent (CxA) to develop and implement their commissioning plan. The owner is responsible for developing his or her own project requirements document and the design team is responsible for using the OPR to develop the BOD.
The commissioning agent reviews these documents for clarity and completeness, then uses these documents to guide the commissioning process.
What is a Commissioning Authority (CxA)?
Commissioning is typically accomplished by an independent third party called a Commissioning Authority, aka Commissioning Agent, or CxA.
The CxA should be engaged early in the planning and design process (ASHRAE refers to this as the “project inception” stage), not engaged after construction. By engaging the CxA early on, the CxA may ensure that the owner’s requirements are implemented in the building design as well as in the development of the building system’s operation and maintenance manuals.
The basic objectives of commissioning noted in ASHRAE Guideline 0 include:
- Clearly documenting the Owner’s Project Requirements (OPR)
- Provide documentation and tools to improve the quality of deliverables
- Verify and document that systems and assemblies perform according to the OPR
- Verify that adequate and accurate system and assembly documentation is provided to the owner
- Verify that operation and maintenance personnel and occupants are properly trained
- Provide a uniform, effective process for delivery of construction projects
- Deliver buildings and construction projects that meet the owner’s needs, at the time of completion
- Utilize quality-based sampling techniques to detect systemic problems, as such sampling provides high value, efficient verification, accurate results, and reduced project costs; and
- Verify proper coordination among systems and assemblies, and among all contractors, subcontractors, vendors, and manufacturers of furnished equipment and assemblies
Unfortunately, no current building codes or regulations require building commissioning even though its benefits are numerous.
According to the Whole Building Design Guide (WBDG), building commissioning can improve new building energy performance by 8% to 30%2.
In addition to the energy savings, commissioning also ensures a facility is built safely to code and operates the way it was intended to, which will save the owner and/or occupants money in operations and maintenance (O+M) costs.
Is Commissioning the Same as Testing?
Commissioning is not a one-time event that happens after a building is initially constructed.
Commissioning is an on-going process that begins in the initial building planning and design phases and follows through construction and then through the operational lifespan of the building… Therefore, the term “commissioning” should not be conflated with “testing”. Testing is an important part of commissioning.
ASHRAE Guideline 0 states that the goal of commissioning is:
“…to provide a uniform, integrated, and consistent approach for delivering and operating facilities that meet an owner’s ongoing requirements” and “to reduce the cost of delivering construction projects and increase value to owners, occupants, and users.”
What are the Types of Building Commissioning?
There are three main types of commissioning processes for buildings:
- Commissioning: The plain term “commissioning” typically refers to the initial process of commissioning a building that is newly constructed or one that is undergoing the design and construction process.
- Recommissioning: Recommissioning refers to the follow on commissioning of an existing building that has already been commissioned once before.
- Retro-commissioning: Retro-commissioning refers to the commissioning of an existing building that was never commissioned when it was initially designed and constructed.
However, beyond these types of commissioning, there are important nuances in their implementation. The nuances have to do with who on the project team is in charge of commissioning the building and what verification and reporting is done for the owner.
What is Technical Commissioning?
If LEED buildings are commissioned by default, why do studies indicate that as many as 28-35% of LEED certified buildings fail to meet their energy-use projections?
A possible answer is the type of commissioning that is done:
- Process Commissioning: In process commissioning, the Commissioning Agent is one level removed from the performance verification. Process commissioning works as follows3:
- The commissioning agent (CxA) provides the outline of the commissioning process to the project engineers and/or contractors.
- The engineers and/or contractors act as the project’s technical experts, following the CxA’s guidelines.
- The engineers and/or contractors provide a sampling of test results to the CxA. The test results are for work in progress or work that is completed.
- The CxA observes these processes and confirms that the processes are done.
- Technical Commissioning: In contrast to process commissioning, technical commissioning is based on hands-on inspections, functional testing and verification of building systems performance by the commissioning authority directly. Unlike process commissioning, technical commissioning does not rely on sample data observed, collected and provided to the commissioning agent by others. In technical commissioning the commissioning agent is the final expert who actually performs proper testing on all building systems. 4
What is LEED Fundamental Commissioning?
Fundamental commissioning is a term for the certification prerequisite in Leadership in Energy and Environmental Design (LEED) in the Energy and Atmosphere credit category. Fundamental commissioning is mandatory in the LEED certification process in LEED 2009 and LEED version 4.
Fundamental commissioning can be thought of as a the best practices completed by the commissioning authority in ensuring that building performance requirements are identified early in a project’s development and verifying that systems have been installed in compliance with those requirements.
What is LEED Enhanced Commissioning?
Commissioning requirements are included in numerous green building design systems, including the Leadership in Energy and Environmental Design (LEED), Green Globes, and ASHRAE Standard 189.1.
As mentioned above, LEED rating systems have a prerequisite for basic commissioning (EA Prerequisite 1: Fundamental Commissioning and Verification) as well as a EA credit for Enhanced Commissioning.
The basic difference between the LEED prerequisite and credit is that the prerequisite is required for LEED certification, while the credit is optional.
The prerequisite’s intent is to “Verify that the building’s energy related systems are installed, calibrated and perform according to the owner’s project requirements, basis of design, and construction documents.” The basic requirements for the prerequisite include designating a CxA who is independent of the design and construction management teams, but may be an employee of the same firm. The CxA may also be an employee of the building owner. The CxA is to required to review the OPRs as well as the Basis of Design (BOD), to develop and incorporate commissioning requirements into the construction documents, develop and implement a commissioning plan, verify the installation and performance of the systems to be commissioned, and complete a summary commissioning report.
The intent of Enhanced Commissioning is to “Begin the commissioning process early during the design process and execute additional activities after systems performance verification is completed.”
The additional requirements of Enhanced Commissioning, above and beyond the prerequisite, include the following:
- Designating an independent CxA to lead, review, and oversee the completion of all commissioning process activities prior to the start of the construction documents phase.
- Conduct, at a minimum, one commissioning design review of the OPR, BOD, and design documents prior to mid-construction documents phase and back-check the review comments in the subsequent design submission.
- Review contractor submittals applicable to systems being commissioned for compliance with the OPR and BOD concurrent with A/E reviews and submitted to the design team and the Owner.
- Develop a systems manual that provides future operating staff the information needed to understand and optimally operate the commissioned systems.
- Verify that the requirements for training operating personnel and building occupants are completed; and
- Assure the involvement by the CxA in reviewing building operation within 10 months after substantial completion with O&M staff and occupants.
In order to ensure that buildings operate not only as they were intended by the design, but also that all of the owner’s requirements were included the design to begin with, it is imperative that the commissioning process is started at the beginning of the design inception stage.
Recommissioning is important to make sure that buildings continue to operate at their highest efficiency throughout their life span, and retrocommissioning can make an existing building that had never been commissioned before operate much more efficiently and save money.
From a return on investment standpoint, when considering an energy conservation measure (ECM) for a building that will have a payback that can be calculated on a straight-line basis, commissioning is often considered the “low-hanging fruit.”
- The American Society of Heating, Refrigeration and Air Conditioning Engineers
- Whole Building Design Guide
- ASHRAE Journal: Dave McFarlane, Member ASHRAE, June 2013
- ASHRAE Journal: Dave McFarlane, Member ASHRAE, June 2013