When explaining the HVAC commissioning process to clients, industry veteran Charlie Cochrane, president of Cochrane Ventilation Inc., Wilmington, MA, likens it to a routine physical.
“Think of the building as the human body, the HVAC system as the respiratory system, and commissioning as the physical exam,” Cochrane says. “Commissioning is looking at the whole picture, the ‘make sure I’m healthy, doc’ exam. HVAC commissioning is just looking at the microcosm of the whole or the ‘check my respiratory system’ visit."
While HVAC commissioning – the testing and verification of a system’s efficiency and optimum performance – is the ultimate way to discover if your facility’s HVAC system is running as it was designed, it’s important to remember that the process is merely a highly integral facet of a larger quality assurance process known as building commissioning.
“Other things in the body can contribute to the health of that respiratory system,” Cochrane notes. “The HVAC does not stand alone.”
This process of documentation, training, adjustment, testing, and verification is performed to ensure that a facility operates, in the case of new construction, in accordance with the owner’s documented project requirements and construction documents. In an existing facility, commissioning seeks to identify causes and recommend solutions in typical problem areas of system integrity, including high energy costs, poor comfort, indoor air quality, and other failures, depending on the systems involved.
The primary goal of the commissioning process is to provide a safe, healthy, and comfortable facility, while also improving energy performance and reducing operating costs. It also can improve orientation and training of the operations and maintenance (O&M) staff, as well as a building’s documentation.
“It is the owner’s optimum quality assurance program,” says John A. Heinz, co-author of The Building Commissioning Handbook, Second Edition and a 30-year veteran of various facilities management positions at the University of Washington, including plant maintenance officer, director of the physical plant department, and director of engineering.
But commissioning is more than just good O&M on the part of the facilities team. It identifies and corrects deficiencies in the system, which can range from design and installation errors to failed equipment, poorly tuned controls, and improper control sequences.
“Commissioning steps back to ask what should equipment and systems be doing and then verifies performance against that ‘What should it do?’ benchmark,” says architectural engineer Walter Grondzik, a consultant in Tallahassee, FL. “The bottom line is savings in energy and improvements in outcomes such as production and productivity.”
Firm Foundation in HVAC
According to energy-efficiency experts at Portland Energy Conservation Inc. (PECI) in Portland, OR, commissioning is increasingly recognized as an effective process to improve building performance, reduce energy use, and improve indoor air quality, occupant comfort, and productivity. A 1998 study conducted for the Department of Energy (DOE) estimated that more than $40 million in potential energy savings could be gained from commissioning only 1 percent of existing buildings greater than 25,000 square feet.
“Most of the work is reported in HVAC systems,” says Mark Tuffo, project manager with the Northwest Energy Efficiency Alliance in Portland, OR. “We’re just scratching the surface with telecommunications, life safety, lighting, and building controls.”
While total building commissioning encompasses a myriad of systems (including lighting, life and fire safety and building controls), the process did spin out of the growing desire of the facilities industry to design, install, and maintain the most efficient HVAC systems possible. HVAC commissioning is what got the commissioning movement off the ground.
“Commissioning got started with a focus on HVAC,” explains George Bourassa, Chicago-based senior vice president and national director of commissioning services at the engineering firm Carter & Burgess. “As commissioning evolved, the focus has gone to other systems to be included in the scope.”
Why should HVAC get the majority of the scrutiny? For starters, HVAC equipment is one of the major energy consumers in a building, with fan energy alone using up to 30 to 70 percent of total consumption, depending on the building type, notes David A. Sellars, technical manager at PECI.
Second, experience indicates that 75 percent of commissioning work and 90 percent of the problems uncovered in a commissioning project are related to HVAC, Heinz notes.
“Just because equipment is running does not mean it is as intended, as per spec or per manufacturer’s requirements,” Grondzik notes.
This is where commissioning enters the picture. The process, however, differs in execution for new buildings and existing buildings.
Commissioning New Systems
In new facilities, a properly developed commissioning program is a rigorous process that should begin in the pre-design phase and continue through the design, construction, and life of the facility. One that is implemented early on and continues through to the end of construction assures that a project will be completed on schedule and on budget, experts say.
“Unfortunately, most owners put off getting into commissioning until late in a project – maybe during construction or perhaps late in the construction documents phase of a project,” Heinz says, adding that it is best to write large commissioning initiatives into the front section of the project specification to tell the contractor “beyond a shadow of a doubt what has to be done in terms of commissioning.
“This has a huge … and very positive impact on how the contractor ultimately schedules all the work of the project, including integration of the various commissioning activities into the project,” Heinz says.
Even if you miss the crucial pre-design process to begin developing a commissioning process, there’s still time to create a solid commissioning program during the design phase. While not ideal, it’s still early enough to back up and incorporate commissioning into the documentation.
That’s what officials in Ada County did when building a new county courthouse in Boise, ID, in 2000. According to BetterBricks, an initiative of the Northwest Energy Efficiency Alliance, county officials decided to commission the project late in the design phase, after the design documents were nearly complete.
Because it was still relatively early in the process, the commissioning provider worked closely with the project’s design/build firm to accommodate commissioning requirements and use the commissioning plan to establish communications channels throughout the remainder of the project.
A Commissioning Coordination Plan was developed specifying each party’s responsibilities. The county’s facility staff played a major role on the team and took on many of the commissioning responsibilities often reserved for the installation contractor. The commissioning provider also developed an integrated training plan for the facility staff that included defined training objectives and key terms for each piece of equipment.
The commissioning provider’s fee of $220,000 was worth it, county officials say. The county reports a first-year cost benefit, based on cost reductions or avoidances, of $106,590 and annual energy savings of $25,500, based on the cost of electricity of $0.0494/kWh and natural gas of $0.755/therm.
Throughout the commissioning process and upon completion, Ada County officials realized the process’ benefits extended well beyond cost savings. It provided the county with an improved, integrated training schedule for the O&M staff and ensured that the facility was completed and fully operational on time. The county took occupancy of the 330,000-square-foot, 5-story building in January 2002 – on schedule.
“Commissioning helped us move in on time and, more importantly, once we got here, our building performed as it was intended to perform,” says Dave Logan, director of Ada County’s Operations Department.
Monetary returns don’t always immediately reveal themselves. “The important point is that you’re not going to see that investment return during the construction phase,” Bourassa points out. “You may not see it until the first few years in permanent operation and permanent asset management.”
Heinz says not to wait until construction is complete to initiate actual testing. He suggests that testing begin no later than the one-third completion point. While crews might still be pouring concrete on the upper floors, chances are the HVAC team is installing ductwork, terminal units, and other components on the lowest floors. That’s the point when testing by subsystems within the larger system should begin. At such an early phase, problems can be identified and corrected before all system components are installed.
“We test as soon as the components are installed,” Heinz says. “If things don’t work smoothly, we tell the contractor, ‘Sorry, you have to change it.’ You need to make these changes before they become critical path items for the project.”
PECI’s Sellars says there are probably tens of thousands of terminal units out there that have never worked or worked properly, and the building owners probably don’t even know it.
“If you never made it work, or if you never get the zone control that it can provide, the building is working as one big zone building rather than a 10-zone building. How silly is that?” he asks.
Sellars likens it to buying a widescreen TV that needs to be hooked up to a cable network to work. You buy one for every room in the house, but you only have cable in the family room, so that’s the only television that you use. The technology is there, but you’re not using it. You’ve never made it work, so you’re not seeing the benefit.
Commissioning lessens the chance that part of a system will not work. It makes sure all the things you bought and had installed perform the way they were intended to perform. “Buildings are complicated machines. There are going to be problems, but those problems shouldn’t be a surprise,” Sellars says.
Delving into Existing Facilities
But what about the surprises building owners seem to keep uncovering in existing facilities they’ve added to their portfolios?
Information from PECI states that too often, building owners inherit systems that have deteriorated over years of use. Building documentation is incomplete and components and equipment are missing or incorrectly installed. Furthermore, common airflow problems result in too much or too little building ventilation.
Existing building commissioning is referred to in the popular ASHRAE commissioning guidelines as retro-commissioning (commissioning in existing, un-commissioned buildings) or re-commissioning (commissioning in previously commissioned buildings). While some in the industry prefer to refer to these practices simply as “commissioning,” saying that the term “retro” can be confusing, others say the ASHRAE’s definitions of retro-commissioning and re-commissioning are the preferred standard.
Regardless of terminology, commissioning of existing buildings plays an important role in overall building performance and energy savings.
“Returns could be pretty substantial if the system performance has drifted substantially from ideal performance,” Bourassa says. “The owner could be paying a lot of money in utility premiums that wouldn’t be the case if the system were ideal. Uncovering issues and correcting them so that the systems do perform to an ideal level is where retro-commissioning comes in.”
Retro-commissioning also helps establish benchmarks for the systems already in place. The lack of existing benchmarks is the real challenge of the retro-commissioning process.
“In a new building, we can expect to find a list of criteria we call the ‘owner’s project requirements,’ or the owner’s expectations of system performance in the building. It provides a benchmark that we measure against. In retro-commissioning, that document doesn’t always exist,” Bourassa notes. “In retro-commissioning, you have to step back and establish that criteria at the same time you are doing the commissioning.”
Because systems often evolve over a period of time to suit different loads and requirements in a building, it’s often impossible to go back to the original design and say here’s what we are measuring against. People who were initially involved might no longer be available or might not remember the original design intent.
Once a new benchmark is established, you can measure and test against that, just as you would in a new building commissioning project.
“When you get into a building that is 10 to 15 years old, you safely can assume some level of mortality failure has occurred on the system,” Heinz says.
The most common trigger for developing a retro-commissioning initiative is that somebody in the facility has identified a problem with system performance. “How many buildings have you gone into where one part is hot and another part is cold?” Cochrane asks. “You’re throwing money away overheating some parts, while other parts of the space are far too cold. Retro-commissioning of existing systems is going to help identify and address problems like that.”
Typical red flags that launch retro- or re-commissioning include the following:
Severe airflow pressurization problems.
Recurring equipment failures.
Excessive comfort issues, i.e., IAQ or temperature control.
High energy bills compared to buildings of similar types.
“Those are four critical factors that indicate a building is in need of an exhaustive review and corrective action that commissioning can provide,” Tuffo notes, adding that a full commissioning program isn’t always the answer. Some problems could be remedied through energy tune-ups or improved operating and maintenance practices.
With this in mind, the Northwest Energy Efficiency Alliance – in cooperation with the Energy Trust of Oregon Inc., Puget Sound Energy, Seattle City Light, and Snohomish County PUD – developed a Building Performance Services (BPS) program that targets existing medium- and large-sized commercial buildings that are larger than 100,000 square feet, consume around 1 million kWh per year, and have complex HVAC systems, as well as energy management and control systems (EMCS).
According to evidence from these organizations, the operating performance of these buildings can be improved, with 5- to 15-percent energy savings often available.
The BPS process is multi-phased and under each of these there are very specific elements that are performed so that each phase is completed to the appropriate level of intensity and identifies remedies and fixes, Tuffo notes.
It starts with a screening process that identifies buildings that are most likely to benefit from improvements to operating performance before incurring the expense of commissioning personnel going on-site. Key screening factors include determining if there are going to be practical opportunities to improve building operating performance and assessing the interest and capabilities of the building ownership and facilities management team.
After screening, the scoping step identifies technical opportunities for high-priority buildings through an on-site review. Findings from the review, teamed with the owner or facilities manager’s business objectives, provide a basis for developing and recommending appropriate follow-up service activities, which include enhanced O&M practices, energy tune-ups, or commissioning.
Enhanced O&M practices result in better building operating performance, experts say. Through BPS, participants in this follow-up activity review current practices and contemplate recommendations for improvements. These recommendations often include suggested changes to management procedures and specific O&M actions targeting particular energy-using equipment.
Energy tune-up activities identify and implement cost-effective operational changes designed to reduce building energy costs. Such suggested changes usually require relatively small investments, such as adjusting equipment or reprogramming controls, or such small capital improvements as adding sensors, calibration or expanding control capabilities. Energy tune-up also includes all the components of enhanced O&M practices.
The third follow-up option is commissioning, which also encompasses the enhanced O&M practices and energy tune services. Use of a formal commissioning process, according to Northwest Energy Efficiency Alliance, is most appropriate when chronic problems exist and the building owner and manager recognizes the need to take significant action.
One thing to take under consideration is that there will be disruption to the workspace and the people in it during commissioning of an existing facility. Building owners and managers need to develop a risk mitigation program before the commissioning begins and make plans to minimize the potential disruptions caused by the work and the need to start-up and shut-down the HVAC system during the commissioning process.
“You have to be ready to take risks and schedule when there is the least disruption to occupants,” says John Jennings, a project manager with the Northwest Energy Efficiency Alliance. “The testing process is not always conducive to the people occupying the space. That needs to be addressed carefully. It’s not insurmountable.”
Selecting a Provider
Whether you are embarking upon a new building commissioning endeavor or a retro- or re-commissioning project, working with an experienced commissioning authority will greatly enhance the success and end benefits of the process.
While the facilities manager may play a key role as the owner’s voice on the commissioning team, most commissioning experts say an outside commissioning authority can provide an objective look into a building and its systems’ performance.
“The success of a project hinges to a great degree on selecting a fully experienced and qualified commissioning authority,” Heinz says. “A number of owners have been disappointed in their commissioning experiences, but that is due, in a large part, to their lack of understanding how to seek and select an appropriately skilled commissioning authority, resulting in selecting a less-than-adequately-qualified commissioning services provider.”
Heinz says the best advice he and others in the industry can give is to urge facilities professionals to first become fully aware of all that is involved in the commissioning process and then learn how to seek and select a quality provider for their project.
A quality provider is important, others say.
“One of my biggest concerns is that there are a number of people who are calling themselves commissioning providers who don’t have a good understanding of the true commissioning process,” Bourassa says. “It’s an industry that is in its infancy and there isn’t yet a well-established certification program for the recognition of service providers. There are programs available, but there are five of them and each have significant differences. Hopefully in the near future we’ll have a gold-standard certification and have confidence in someone at this nationally certified level. For the moment, I think it still is a question of ‘buyer beware.’ ”
Educating yourself about the commissioning process is the best way to seek out the most qualified provider for your initiative. It’s also the best way to understand what the process will do for your building. It’s important to understand that retro-commissioning is the diagnosis, and may or may not be the cure for building problems, depending on the complexity of the problems.
“It is not the corrective measure,” Cochrane says. “It is the fact-finding measure. Once you have the data, you can move forward to balance the system and meet the building’s demands. And even if you don’t feel commissioning is important, it is important to know what your building’s ventilation system can do and what it is capable of doing. Current and capable. That’s good knowledge to have.”
Robin Suttell (firstname.lastname@example.org), based in Cleveland, is contributing editor at Buildings magazine.