It is far easier and less expensive to maintain a building that operates correctly than to maintain one that does not.
In the construction industry, artificial schedules often drive the completion of a building. With so much riding on the opening of a building — including occupants’ schedules and the owner’s revenue stream — the result too often is a new building that was built incorrectly or that contains equipment not installed nor tested properly. As a result, it doesn’t operate as designed.
While contractors usually are required to document the proper operation of buildings, they might not be held to that requirement in the rush to move in occupants. The equipment and systems might be turned on but not set up and operating at maximum efficiency.
Getting it built correctly should be just as important as getting it built on time. Too often, it is not, and that is where building commissioning comes in.
Definition and Benefits
Simply stated, commissioning is the systematic, quality-focused process of ensuring facilities, systems and equipment perform according to design intent. The process assures owners and occupants that the building will meet their needs and expectations.
The commissioning process provides a certainty of outcome. It ensures that buildings and their systems function and operate properly and that they are maintained correctly, resulting in greater efficiency.
Facility commissioning was created in response to numerous problems with mechanical, electrical and plumbing systems occurring after a building was turned over to in-house staff and occupied. Typically, maintenance and engineering managers' resources are minimal, and they don’t have time to allocate internal resources to working out system bugs or to finish construction after a building has been turned over.
Commissioning addresses the gap between a building that doesn’t work as intended and an already overburdened maintenance and engineering staff.
Commissioning provides numerous benefits to engineering and maintenance managers, occupants, and owners, including:
- improved building performance
- improved operator and maintenance knowledge and training
- reduced costs — both first costs and life-cycle costs — related to construction, energy efficiency, and maintenance
- reduced warranty callbacks
- improved documentation
- fewer occupant interruptions
- improved indoor air quality
- smoother building turnover and occupancy.
Perhaps the biggest benefit of commissioning is a more energy-efficient building. Many studies show that a commissioned building saves 10-20 percent of the total utility cost compared to a non-commissioned building.
Improved indoor air quality (IAQ) is critically important as it relates to the health of building occupants. To combat mold-related problems and sick-building syndrome, commissioning ensures a building is pressurized and has the correct fresh air changes for IAQ.
For example, if a building must use 20 percent outside air for IAQ code requirements, less outside air might cause occupants to become sick and the building to become negatively pressurized. Negative pressure can be conducive for mold growth and subjects the building to excess energy use. If outside air is more than 20 percent, energy costs can needlessly increase. Commissioning can ensure a building is both efficient and safe by verifying outside air use and controls.
More managers are realizing the positive impact commissioning provides for their maintenance staff. Knowledge and understanding of installed systems and their design and operation have a great long-term impact on both operating and maintenance expenses.
The benefits of staff training are not limited to new construction and expansion projects. Retro-commissioning of existing facilities can greatly increase the awareness and understanding of the operations and maintenance staff. The key here is system operation, not individual components or equipment. Commissioning documents the ways system components most efficiently operate together to reduce energy costs.
Commissioning also delivers more useful operations and maintenance (O&M) manuals about specific pieces of equipment. While maintenance professionals can easily access to various O&M manuals from manufacturers or download them from the Internet, these are generic and contain information that is not specific to equipment that actually has been installed.
Manufacturers also offer a range of products related to capacity and add-ons, which can complicate understanding the equipment and systems installed. A commissioning agent can format these manuals in a user-friendly, encyclopedia-like format with specific information on the installed equipment and systems.
These resources provide documentation on the way equipment should be operated and preventive maintenance procedures and schedules, in addition to information on spare parts. These manuals can greatly minimize productivity frustration for managers.
Commissioning provides short- and long-term benefits, so managers should view it as an investment rather than an expense. In terms of total cost of ownership, managers must consider equipment life-cycle costs and energy efficiency, in addition to the acquisition or first cost of building equipment and systems.
Costs for commissioning can range from 1.5 percent of the total construction costs on a $5 million project to 0.3 percent of the total construction costs on a $110 million project. For new buildings, it is important to note that owners typically have a 3-5 percent contingency budget for problems that might arise during construction. If they would commit part of that budget to commissioning on the front end, they ultimately would spend less overall and obtain a more efficient building.
The return on investment (ROI) seen through commissioning is worth the effort. The standard baseline used in the industry is $3 savings for each $1 spent on commissioning. While the standard ROI is $3, it actually can range up to $11. It is well documented that commissioning maximizes efficiency and cost savings, and the timeframe for payback of commissioning fees can be less than two years.
Managers who have problems with a building, particularly problems related to HVAC systems, are not alone. Lawrence Berkeley National Laboratory studied 60 new buildings and determined that:
- 50 percent have control problems
- 40 percent have HVAC problems
- 15 percent are missing equipment
- 25 percent have malfunctioning facility management systems, economizers or drives
- 60 percent of insurance claims are related to HVAC systems
- the leading source of complaints is HVAC systems.
Managers first should commission equipment and systems that have caused the most problems in the past. But at a minimum, they should consider commissioning HVAC systems and control systems because such a strategy often results in the greatest energy savings.
Control systems drive many elements of an HVAC system and have become so sophisticated that few end users really understand fully how to use them to optimize system performance. Typically, someone unfamiliar with the ways the individual pieces of HVAC equipment operate these systems installs control systems to provide comfort control. They might fail to program or calibrate them correctly on the front end.
In addition, maintenance professionals unfamiliar with these systems might bypass them completely. Commissioning ensures control systems work properly and that staff members receive training on their operation and maintenance.
Emergency power systems also can benefit from commissioning, especially in medical and high-tech facilities. These facilities cannot afford downtime or a loss in power, as the cost of such a failure can be substantial. It is important to commission the emergency distribution system and to test other systems — such as air-handling units, exhaust systems, chilled- and hot-water systems, temperature and pressurization systems, and fire-alarm systems — by transferring each one to emergency power and back to normal.
Commissioning: A Practical Example
A90,000-square-foot major sport and entertainment complex offering state-of-the-art facilities for athletics, concerts, tradeshows and conferences at a Division I university used commissioning services during construction. The organization tested mechanical, emergency power and life safety systems, including:
The commissioning process identified several problems. The controls caused the lag chiller to remain on 100 percent of the time, which wasted energy and caused excessive wear and tear on the equipment.
On the AHUs, the airflow monitoring systems were not functioning, which could have an impact on overall building pressure and IAQ issues. It also could lead to mold problems during summer months. Controls sequencing failed to start a secondary chilled water pump in a freeze-protection sequence, which would have resulted in frozen and burst coils.
Finally, on one AHU, wiring from the fire alarm system to the AHU control panel was not terminated and could have caused smoke to be distributed throughout the building in the event of a fire.
The return on investment for this project was $11 savings for each $1 spent on commissioning, resulting in an estimated $422,408 in total savings.
— Rusty Ross
Rusty Ross, P.E., LEED AP, is director of commissioning services for SSRCx a total facility commissioning provider and subsidiary of Smith Seckman Reid a Nashville, Tenn.-based engineering design and facility consulting firm.