Tips and tricks for commissioning, balancing buildings
Building commissioning is one of the most important (and complex) types of projects an engineer can be tasked with. This overview provides insights for commissioning building systems.
- Jerry Bauers, National director of commissioning, Sebesta Blomberg, Kansas City, Mo.
- Michael P. Feyler, Co-director, building solutions group, RDK Engineers, Andover, Mass.
- Robert J. Linder, PE, Senior project manager, Karges-Faulconbridge Inc., St. Paul, Minn.
- James Szel, Senior vice president, Syska Hennessy Group, New York City
- Geremy Wolff, Commissioning manager, McKinstry, Bellingham, Wash.
- Barney York, Project manager, RMF Engineering, Baltimore
CSE: What challenges do building commissioning projects pose that are different from other projects?
Jerry Bauers: As a provider of commissioning services, the biggest challenge we face is managing the schedule of commissioning project execution. At every phase of a project, our work is entirely dependent upon the logical and timely execution of the work of other members of the design and construction team. And, in many cases, the incentives that these team members have—both financial and emotional—are in conflict with the requirements appropriate to a disciplined and effective commissioning process. The challenge is to engage the project team members in the notion that an effective construction process and schedule adds value to the results of every member of the team.
James Szel: The biggest challenge to commissioning is to create the environment where everyone from the owner to the contractors to the vendors feels like they are a valued part of the commissioning team. Commissioning is only as important as the owner makes it. When the owner (or its representative) is engaged and actively participating in the process, it really makes for a cohesive, productive team. Another challenge is the timing of the involvement by the commissioning agent (CxA). The CxA should be engaged early in the project to be an integral part of the team, for tasks such as peer reviews.
Geremy Wolff: Managing the relationships between the contractors, the architecture/engineering team, and the owner can be difficult at times. If everyone is on-board with collaborating to find solutions, it’s great, but there are times when it feels like all we hear is “that’s not in my scope.” This seems to be more prevalent on low-bid work versus design-build or projects with performance requirements. But it is a serious challenge for us.
Some project teams expect the commissioning provider to know everything about everything. This just isn’t the case, especially considering commissioning has expanded into disciplines other than mechanical, electrical, plumbing (MEP), and fire protection, such as building envelope. As the commissioning provider, you don’t have any authority. Through our commissioning process we identify issues and communicate them back to the team, but there is typically no contractual obligation for them to do anything about it. The design-bid-build process used today has not significantly changed in more than 100 years; however, commissioning was not introduced until the late 1980s, so we are still “the new kids on the block.” Integrating our process into the well-established design-build process has proven to be challenging. We still find ourselves educating design and construction professionals on what is commissioning (it’s not just “testing at the end”) and when it should be implemented (it’s never too early).
Barney York: Building commissioning projects are unique in the sense that another party is introduced and integrated into the overall design and construction process. This can create challenges because the CxA’s role has a natural tendency to become adversarial due to the additional oversight the commissioning process adds. In addition, the project schedule can become a challenge as the project completion now requires a contractor to demonstrate a building is not only substantially complete, but functionally complete as well. Commissioning tasks required to demonstrate functional completion must be integrated into the project schedule, and the team must work collaboratively to ensure the owner’s target date is met.
CSE: Please describe a recent commissioning project—share challenges you encountered, how you solved them, and aspects you’re especially proud of.
Michael P. Feyler: On a recent data center project, the client was to incorporate hot aisle containment. In order to validate the hot aisle/cold aisle design, mock-ups of each pod were built. A testing procedure was developed to validate the capacity of the fan-wall design to maintain the designed cooling load, verify the control and heat distribution, and validate the fan wall sequence of operations. Temperature sensors were placed at points within each hot and cold isle, with humidity sensors spaced within the data hall to monitor the temperature and humidity distribution during the testing. RDK developed the load bank placement and sensor scheme, and calculated the total anticipated load for each rack. Information was logged to the building automation system (BAS). RDK worked closely with the controls contractor to develop commissioning pages on the building management system (BMS) that not only captured the information from data hall, but also enabled the team to review mechanical and electrical data from key equipment such as the switchgear, uninterruptible power supplies (UPSs), chillers, and pumps.
Robert J. Linder: We still encounter instances of contractor nonperformance. The lack of care taken by contractors to truly pretest their work leads to incomplete systems and the inability of the CxA to perform functional testing. We can write it up as such and walk away until it is complete, but this does little to assist the project team in meeting its schedule. Instead, we like to actively coordinate retesting and often document the deficiencies on a punchlist. We cover ourselves for the increased scope of work by developing a thorough commissioning specification that outlines how we will be compensated, by the responsible contractor, for additional services upon its lack of performance.
Bauers: We recently completed the commissioning of a BSL-3 laboratory for a northeastern U.S. university. The university built a new BSL-3 lab to support the efforts of a key academic research team. With grants an important element of university funding, this lab was key to the university’s effort to develop its biological research capability. While the technical challenges of the laboratory were significant, we were able to identify the need to develop standard operating procedures for the university’s engineered environmental systems as well as its laboratory procedures. Leveraging our experience in commissioning these facilities, we were able to assist the university to both bring its facility on line and develop the procedures necessary to achieve U.S. Centers for Disease Control and Prevention (CDC) approval for operating the laboratory.
Szel: Working with a Silicon Valley client, we were commissioning the complete removal and replacement of a UPS system with live critical load. We worked with the vendors and the owner to create a detailed schedule that included load testing the temporary generators that were brought in to power the load during the demo and installation process. Risk reviews were performed to ensure risks were mitigated during critical load transfers. Because of the spirit of collaboration and cooperation (and an excellent electrical contractor), we completed the project and had the new UPS carrying the critical load ahead of schedule.
York: RMF was recently responsible for providing third-party U.S. Green Building Council LEED commissioning services for a large detention center facility. The project installed a complex smoke control system, which must be able to control smoke within any one of the 27 smoke “zones.” With building occupants that cannot easily be evacuated in the event of a fire, proper smoke control is essential. The system functioned by maintaining a pressure differential across adjacent zones. The variation in construction type—some areas were leaky while others were tightly constructed—made it very difficult to establish proper pressurization. Our team worked closely with the construction manager and designer, often at night, to determine the necessary airflows that allow the system to operate properly. The end result was the system passed the local fire inspector’s inspection successfully the first time and the facility managed to open three months early.
CSE: What tips can you offer engineers working on commissioning projects?
Feyler: During the design phase, a meeting should be held for the commissioning engineer and the design engineer to review the systems chosen and the sequences of operations, plus a controls integration meeting to share experiences on similar systems and the results from previous projects with similar systems and building types for the systems being included within the design. During the submittal phase, on complicated projects, it is beneficial for the design engineer, CxA, and controls contractor to meet prior to the final approval of the control scheme to ensure that all are in agreement on the control mythologies and sequences. During the construction phase, after the control submittal is approved, the commissioning engineer drafts the functional testing documents. Sharing the draft functional testing documents with the design team and contractors for their review and input will ensure that prior to the release of the final testing documentation, all parties have reviewed and provided input on the documents, and all parties have a though understanding of the design intent. A beneficial procedure our team has incorporated into the commissioning specification is for the contractors to “dry run” the system prior to commissioning. This requires the contractors to test the systems using the functional performance tests, to debug and check programming and operation. RDK requires a sign-off of the dry run prior to site commissioning. All of the above ensure that the contractor has a full understanding of the system operation prior to commissioning.
Bauers: Effective execution of any field testing effort is almost entirely dependent on preparation prior to arrival at a project site. While a test procedure can be a long, complex process, its component parts should be quite simple and clear. Each step in a test procedure should be specifically designed to demonstrate an element of performance clearly and without confusion. And the purpose of that step (or series of related steps) should be clear to the execution team. In the end, testing is only valuable if it either demonstrates success or points clearly to corrective actions that lead to success. Preparation prior to going to the field, understanding the systems to be tested, the objectives of each step of the test, and strategies to deal with the unexpected are essential to effective field execution.
Wolff: There are a number of tips:
- Break it down into manageable steps; you can’t eat an elephant in one bite.
- Take the time to review and play devil’s advocate with the sequence of operation. Make sure that the sequence covers all aspects of operation including what happens during a loss of power and return to normal power after an emergency (often ignored). And, if an engineer is going to “borrow” a sequence from a previous (similar) project, take the time to go through the sequence and make sure all the changes are made to make this one applicable to the project (often ignored).
- Have the installers pretest the systems before you attempt to “commission” them. There is no greater waste of time than organizing a test and getting everyone out to the site and in place only to find out the contractor running the test is not ready, the system is not ready, or the contractors don’t understand their role and responsibility.
- Change the way people view “functional testing.” It should not be viewed as “well, let’s flip the switch as see what happens.” Functional testing should be viewed as “functional demonstration.” We are not testing to see if it works, but rather demonstrating that it works in accordance with the designer’s expectations and the owner’s project requirements.
- Start from the basic concept of “How does it (the piece of equipment/system) turn on and turn off?” If you can’t prove those basic functions, then the rest is meaningless.
- Test from the approved as-programmed sequence of operation, not the engineer’s operating “intent.” The intent is usually vague and is not detailed enough to create a test from.
- Ensure there is time in the schedule for BAS provider and engineer to review the test scripts and provide comments weeks before the test is executed. You might find how you are planning to test the system can’t be done, or that the sequence used to create the test is out of date and no longer applicable.
- Be flexible; know the test procedure you spent all that time on will have to be modified in the field while performing the test.
York: The best tip for engineers working on commissioning projects is to become proactively involved early with the owner and design team and remain involved with both throughout the project. The CxA is there to assist the design team professionals and as such can help designers avoid problematic and costly errors that would otherwise be discovered during construction or occupancy. Early designer involvement helps the CxA better understand the design intent, and together the CxA and design team can incorporate the devices and sequences needed to successfully test and validate the systems operation. Continued involvement and communication with designers during construction and commissioning helps the project team make minor adjustments to system performance as well as helps the designers further their professional development.
Linder: A few tips we press upon our staff include:
- Do your homework; understand the owner’s functional requirements that were to be met.
- There is no substitute for getting dirty on a project; don’t just sit at the direct digital control (DDC) front end observing operations.
- Develop detailed testing procedures and don’t skip steps.
- Validate functionality and DDC reporting of all components before you test equipment; don’t just trust the controls contractor.
- Functional verification is not complete until all integrated systems testing is finished and conformance to the design intent was observed and documented.
Szel: Understanding the sequence of operation is key. Review the operations and maintenance (O&M) manuals for information on how the equipment operates. If the sequences don’t make sense, don’t be shy about making that phone call to the engineer of record. If it still doesn’t make sense, engage the vendor’s technical group. I recently went to a factory witness test at a major chiller vendor. We had some very detailed technical questions. The vendor brought in its lead installation technician to speak with us. He was a great resource. It is important to remind the team that the end goal of commissioning is to hand over a quality, operational building to the owner.
CSE: What are some of the tools and systems you rely on to commission projects?
Feyler: In addition to the obvious ladders for above-ceiling observation, heat guns, digital thermometers, light and sound meters, stop watch, and laser pointers are used during the testing phase. During testing of sophisticated systems, our firm will have verbiage in the commissioning specifications that the contractor is to provide a third-party certified testing agency for infrared scanning, power quality metering, and NETA electrical testing. RDK will also carry a third-party test-and-balance (TAB) contractor for the spot checking of the testing and balancing report, and in some cases the owner has RDK carry the TAB contractor under the commissioning services contract to facilitate the TAB contractor for the entire project. This scenario is beneficial to the owner and the CxA.
Szel: Some key tools are infrared temperature scanners, data loggers, and power quality monitors. It is important for there to be skilled technicians who can interpret the results. Also, patience is important for those days when the plan just doesn’t go as expected.
Wolff: It’s pretty typical for our commissioning engineers to use a digital multi-meter, noncontact thermometer, digital thermometer with insertion probes and thermocouples, IAQ meter, digital manometer, thermal imager, data loggers, laptop/tablet, and digital cameras.
York: Every CxA’s toolbox should contain a wide range of physical items: flow hood, pressure gauges (water and air), thermometers, hygrometers, data loggers, anemometer, voltmeter, ammeter, ground fault interruption (GFI) tester, screwdrivers, rulers, and camera; but more importantly should include proven process tools to collect and organize the enormous amount of data collected on a commissioning project. The CxA should also be able to rely on ASHRAE, NETA, NFPA, and AABC guidelines to help evaluate system performance.
CSE: When re- or retro-commissioning structures, what challenges do you encounter, and how do you overcome them?
York: Re- and retro-commissioning projects introduce the unique challenge of trying to understand how the facility was originally designed and also how it is currently operating. The existing documentation (design, record documents, and equipment information) is typically sparse or non-existent, and the CxA must rely on intensive field investigation and end user interview sessions to establish the baseline. In addition, system functional testing is problematic because the facilities are occupied. The CxA must be prepared to work off-hours and become creative with testing as to not interrupt the end user’s daily activities.
Bauers: The most significant challenge in retro-commissioning or re-commissioning is uncertainty. Simply understanding the nature and configuration of installed systems requires an iterative process of discovery. Dealing with the expertise, motivation, and resistance of the operating staff requires a subtle approach to engaging those individuals most knowledgeable in the character and operating challenges of a building system as full partners in the process. Finally, collaboratively constructing a process to both identify and quickly implement operating and deferred maintenance opportunities is essential to creating cultural changes that allow the implemented solutions to become a part of the culture of the operating building.
Szel: Challenges with retro-commissioning start with the scope of work. Clients understand the goals but often have difficulty preparing a good phased scope of work. Because of that, often the bids aren’t apples to apples and the client may not achieve the full expectations. Invariably with a re- or retro-commissioning project, the documentation is out of date, incomplete, or completely missing. Understanding how the system currently operates is critical. This is where the building controls vendor is the most helpful resource. The technician will be able to dig into the programming and extract the sequences of how the building is actually running. Don’t assume they can pull everything you need without direction, though. You will need to work with them and help with the documentation process—this will be invaluable later when you are discussing recommendations with the team.
Wolff: The first big challenge is a functioning control system. If the target building does not have a functioning DDC system, the challenge of improving functionality is almost impossible. Retro-Cx customers are usually interested in “low-cost/no-cost” solutions, and if the project does not have a DDC system or if the controls are incomplete or are in such a poor state that replacement is warranted, then low-cost/no-cost solutions are usually not available since the investment of a new or retrofitted DDC system is cost prohibitive. The second major challenge is that unless the building is fairly new, the documentation, if it exists, is usually unreliable. This can create challenges in every aspect of the existing building commissioning project. For this reason we typically recommend a multi-step approach to existing building commissioning that allows us to adjust the program as we go. The third challenge is one of identifying and understanding the purpose and goals of each retro-commissioning project. Why does the customer want to do retro-commissioning on his building? What is the goal? As the provider you need to know if they are interested in energy savings, operating improvements, both, or something else.
Feyler: The investigation phase is generally the most time-consuming and challenging. As-built documentation from the earlier design, retro-fitting, or improvement projects that may have taken place, construction final documents, auction trust closeout (ATC) documentation, and O&M manuals are difficult for the owner to provide. Additionally, have the system performance and operation been changed due to tenant complaints, general tweaking of the systems to answer the complaints, or a change of use within the building or spaces? These changes are almost always not documented on drawings or facility maintenance plans. Another challenge is the facilities maintenance plan—how well has the facility been maintained, and when was the last time sensors and meters were calibrated? Is there an existing testing and balancing report, or will there be a need to perform a existing condition air and water flow verification during the retro-commissioning investigation plan stage? Will the building envelope be part of the retro-commissioning plan to include the envelope in the investigation? Are the cold and warm calls due to the building envelope issues?
CSE: Does your firm offer third-party commissioning services, and if so, what benefits do you provide as a third-party CxA?
Linder: KFI believes that commissioning is a technical process that requires active, on-site involvement with all project team members. Our technical commissioning approach places an emphasis on physically performing installation verification and functional performance testing with our qualified personnel, in lieu of just reviewing contractor supplied documentation. We don’t just document problems. We use our knowledge and expertise to identify the root causes of the issues, providing the biggest benefit to the owner by identifying solutions. The technical approach provides the owner with true third-party verification of the commissioned systems.
Feyler: RDK Engineers provides third-party commissioning, and most of our projects are such. In addition to the owner preferring the third-party commissioning, it is a requirement of for the U.S. Green Building Council LEED EAp3 Enhanced Credit. The benefit of third-party commissioning is that the CxA can provide to the owner or the owner’s project manager an unbiased report on project deficiencies, whether design or construction related issues. Design reviews are provided by experienced engineers; the engineers that start the project in the design phase follow the project through construction and acceptance, participating in the installation observations, creation of the functional performance tests, and on-site commissioning. The engineer has a though understanding of the equipment and system sequences.
Wolff: Yes, we provide third-party commissioning along with commissioning of our integrated MEP design build and performance/savings guaranteed projects. Being a company that provides commissioning services across a broad spectrum of the industry gives us a unique perspective and resource pool to draw on to solve complex issues. We have in-house design engineers, installers, and service personnel. This allows us the opportunity to draw from their knowledge and experiences to improve our commissioning services and to bring in experts where necessary.
Szel: Syska Hennessy does provide third-party commissioning, which is fast becoming the industry standard. LEED projects going for the Enhanced Commissioning credit are required to have a third-party CxA. The benefit of third party is, since this agent is hired by the owner, it is responsible to the owner and provides a completely unbiased perspective. You basically become the eyes and ears for the owner, in acting on its behalf.
York: Yes, our core commissioning practice is typically contracted as third party. The most evident benefit is that potential conflict of interest does not exist between the CxA and the project team. The CxA can offer an independent perspective, challenge concepts, and offer guidance to the owner, designer, and contractors freely. In addition, the third-party CxA can facilitate healthy conversations and moderate disputes quickly and keep the project moving forward. A skilled CxA can bridge communication gaps and keep the project moving forward.
Bauers: As a National Environmental Balancing Bureau (NEBB) technical commissioning provider, we believe that our teams provide an invaluable technical resource to the design and construction team. We improve the quality of construction documents through effective participation in the design process. We assist in identifying and resolving equipment and installation mistakes while their resolution is both possible and either low cost or no cost. We provide system performance optimization in the acceptance phase by not just testing, but by validating and adapting system performance to the realities of the installed systems and constructed facilities. And, we prepare the operations team—through collaborative inspections and testing processes and training—to sustain optimal performance of the delivered systems.
CSE: ASHRAE Standard 202P, Commissioning Process for Buildings and Systems, identifies the minimum acceptable commissioning process for buildings and systems as described in ASHRAE’s Guideline 0-2005, The Commissioning Process. How have you applied this standard in a recent project, and what challenges did you overcome?
Bauers: We are a NEBB-certified firm. As a member of the NEBB BSC Committee, we developed our procedural standards to comply with the ASHRAE guidelines on commissioning. Given that we have taken this approach, we apply the NEBB standard to commissioning. The challenge in the marketplace that we are finding is that our process and the NEBB standard seem to be more rigorous than many of the processes implemented by our competitors. Using a hands-on approach to commissioning, we are substantially more involved—particularly during construction—than many other firms against whom we price our services.
Szel: Most of our commissioning projects are either for LEED certification or for critical facilities, which have their own specific requirements for commissioning that exceed the ASHRAE standard. With our critical facilities clients, we try to get engaged early in the process so we have input in the commissioning specifications for the vendors and contractors; we often write them entirely.
Wolff: We have not applied 202P specifically to a project, though the principles contained within it align with our standard delivery. Another way to look at this is that McKinstry Commissioning has, in effect, already been providing 202P services, since our delivery method is already in accordance with this standard.
York: I personally have not used the ASHRAE Standard 202P for a commissioning project. The standard was recently released by ASHRAE and most owners and CxAs are still learning the standard. The 202P standard does a great job specifying the minimum commissioning services required to ensure the owner extracts the most value from commissioning. The standard is very similar to the USGBC’s BD&C LEED EA Pre-requisite 1 requirements with the addition of submittal review, systems manual, and training, which we have applied on multiple projects. For systems manuals to be of long-term value, you need an engaged owner in the process—a owner that understands how the systems manual can support long-term operations and maintenance as well as potential system limitations as churn occurs.