Building commissioning challenges, solutions: Electrical, power system
Commissioning, recommissioning, or retro-commissioning, can be a challenge—and the more complex a facility is, the more boxes an engineer has to check to get the job done right. Electrical and power systems must be carefully commissioned to meet code and owner expectations.
- Ray Dodd, PE, CxA, LEED AP , President, Total Building Commissioning Inc., Phoenix
- Kyle G. Hendricks, LEED AP, Energy and sustainability consultant, Environmental Systems Design Inc., Chicago
- Donald H. Horkey, PE, LEED AP, Principal, mechanical engineer, DLR Group, Minneapolis
- David J. LeBlanc, PE, FSFPE, Senior vice president, Rolf Jensen & Associates, Inc., Framingham, Mass.
CSE: What’s the one commissioning issue most commonly overlooked in electrical/power systems?
Horkey: The commissioning of emergency backup generator systems is always a schedule and coordination challenge. It is critical that all parties be on-site to witness the commissioning of these systems. Oftentimes this commissioning activity will need to occur at night when the building is unoccupied to minimize disruption to building occupants.
Dodd: Communication between the emergency power system (generator, automatic transfer switch, UPS) and the BAS. What elements are supposed to be on emergency power are often left out of the design documents or poorly communicated. If the CxA doesn’t have both a mechanical and electrical background, those nuances can easily be missed.
CSE: How have energy-efficiency and sustainability requirements affected your approach to commissioning electrical systems?
Hendricks: A major piece of the energy and sustainability philosophy is metering, and we have seen an increase in the importance of submetering various equipment loads. Verifying meter calibration and confirming meter locations during design review are important steps in the commissioning process.
Dodd: Lighting is a huge consumer of electrical energy. Measurement and verification requires that loads (HVAC, plug, and lighting) are segregated along with metering and submetering are very helpful in determining what equipment in the building is using energy and how it is functioning. These requirements must be established in the design process as they are impossible to implement after construction starts. We focus our efforts on these energy-efficiency and sustainability requirements in the design to make sure commissioning goes smoothly in the acceptance phase of the project.
Horkey: The need for real-time data analysis has increased the need for measurement and verification requirements. These requirements typically lead to significantly more metering needs. The commissioning professional is ideally suited to ensure that the required metering instrumentation is included in the contract documents and is installed in the project.
CSE: If an owner is contemplating U.S. Green Building Council LEED certification or if ASHRAE 90.1-2010 compliance is required, the commissioning of lighting controls is a necessity. Describe a recent project in which you commissioned the lighting and related controls systems.
Dodd: We recently commissioned the lighting control system for a large financial services client in a high-rise building. The space used zoned open office space with private offices on the perimeter. The system was designed so that in the open office lighting levels are adequate for the localized users but not over-lit for the unused open office space. It was a complex sensing system and took several iterations of testing to get the programming right.