Monitoring-Based Commissioning
Judging building performance requires evaluation of the impact the building has upon people, our planet, and profit for the owner. These three factors constitute the triple bottom line and define the metrics by which building performance can be measured and evaluated. Measuring these parameters used to be very difficult and expensive. Now, new strategies that blend information technology with building information and control systems significantly streamline obtaining the information an owner needs to improve and maintain building performance for the life of the building. An example of this is underway in the Albro Falconer Manley Science Center at Spelman College in Atlanta, GA, a historically black college (HBCU) founded in 1881 to prepare women to change the world. Spelman’s president, Dr. Beverly Tatum, is committed to continuously improving the institution’s positive impact for people, our planet, and the financial strength of the college, of which controlling operating costs is of key factor.
A Healthy Learning Environment
A positive learning environment is a combination of many factors of which excellent faculty is one. Another key factor is indoor environmental quality. Occupant productivity and learning ability is dependent on occupant satisfaction. Factors that impact an occupant’s ability to learn are also the same factors that affect an occupant’s ability to be productive. The importance of identifying conditions that impair an occupant’s learning and productivity is one of three metrics needed to evaluate building performance. It is also important to understand the occupants’ activities and what building attributes are needed to facilitate the occupants’ mission.
The start of any existing building commissioning effort is the development of the Current Facility Requirements (CFR). Typically, a workshop is conducted with the various building stakeholders to obtain specific information from the owner, operators, and occupants about how the building must perform to meet their needs. At Spelman, the owners directed the decision-making process used to evaluate recommendations to improve building performance. Operators provided insight to building systems, information they need to improve building performance, and operational constraints. Occupants that use Spelman’s Science Center provided insight to the type of chemicals being used, special needs required to support research, and activities occurring within the building and the functional requirements associated with executing their daily missions.
A Look Into the Systems
Having acquired the CFR from the stakeholders, Commissioning & Green Building Solutions, Inc. (CxGBS) began investigating the building systems. Like many university campuses, much of
Spelman’s campus utility usage information is collected from a central meter. The director of Facilities Management & Services, Mr. Arthur E. Frazier III, AIA, needed a way to measure individual building performance, beginning with utility usage. The initial task was to develop a metering plan to allow for the collection of data on utility consumption. Obtaining information on a real-time basis is important to evaluating operational parameters affecting building performance. Receiving this information into a single system, such as the building automation system, is helpful in collecting the data.
The building automation systems installed in the Science Center was an early generation system, commonly referred to as a legacy system. Legacy systems typically present several challenges in providing data collection due to memory capacity, requiring some updating, as was the case at Spelman. With a new building automation system (BAS) front end, additional memory added to the BAS legacy controller, and new controllers installed to obtain submetering data, the ability to monitor performance began to take shape. In October 2010, water sub-meters that reported consumption directly to the building automation system were installed to record cooling tower make-up and discharge from the Science Center’s physical plant.
The Science Center’s original electrical switchgear had an intelligent meter,
which did not have reporting capabilities beyond visual observation at the switchgear. The maintenance and control
contractor utilizing the current transducers from the switchgear’s existing intelligent meter were able to bring the data
to the BAS system. The initial investigation found that the data being collected from these transducers were off
considerably due to a scaling factor
error in the programming — which
was corrected — making electrical
consumption data available through
the BAS in August 2011.
The initial walkthrough and initial evaluation included an identification
of large openings between the outside
air intake tunnel and the mechanical room, containing the four 20,000 CFM variable air volume air-handling units (AHUs) serving the building, resulting
in more than 12,000 CFM of conditioned air short-cycling back to the air
handlers due to negative pressurization caused by the openings. Evidence was discovered that sections of the AHUs’ supply duct had been over-pressurized, causing
splits at several supply duct joints,
resulting in conditioned air spewing
into the mechanical room. Also, the
domestic water pumping system was
short cycling due to incorrect pressurization of the bladder storage tank used to stabilize pump operation.
The lighting system throughout the building was generally T8 fluorescent lighting. While not the latest technology, it is still a very efficient lighting system. Changing to a higher-efficiency fixture such as a T5 was not within the owners’ required return on investment (ROI). The lighting survey identified several areas that were over-illuminated, allowing some delamping. The addition of lighting controls throughout the building met the owners’ ROI.
Taking the Next Step
The next step in the process was setting up trends on more than 10,000 BAS points within the BAS system to record and store data at 15-minute intervals from the components connected to the BAS. Collection of trend data allows for simultaneously observing the operation of all of the components managed by the BAS. Having this data allows analysis at the component level, system level, and intrasystem and intersystem levels over the actual operating and weather conditions. Analysis of this data identifies operating issues typically invisible to most building operators and control technicians, unless someone has filed a specific complaint that requires operator interaction.
Most operating issues that affect utility consumption go on for long periods of time because no one complains. When occupant complaints do occur, the operator often overrides BAS programming to resolve the complaint. Organizations in firefighting mode are typically so overwhelmed that they forget about the modification, which along with other operational issues, raises operating costs.
Monitoring-Based Commissioning
The value of monitoring-based commissioning (MBCx) is its ability to provide detailed information about operational issues affecting the building performance and assist operators with transitioning out of firefighting mode to reliability-centered maintenance, utilizing the tools provided by MBCx.
MBCx identifies issues not easily recognized by traditional commissioning methods or building operators, provides specific details on the root cause of issues and suggested actions to correct them, and identifies the cost penalty of no action or financial benefit of correction. MBCx provides the feedback loop building owners and operators need to improve and maintain a healthy, high-performing building while providing positive financial impact to the owner by lowering the total cost of ownership.
Spelman College is currently implementing the MBCx process at the Albro Falconer Manley Science Center, which is beginning to provide valuable insight into occupant satisfaction through automated occupant surveys, operational issues affecting building performance, and through the curtailing of utility consumption.
MBCx allows for quick identification of problems on a continuous basis and provides the owner and operators the tools to resolve problems efficiently, saving human resource time and effort, energy and water, and money from being wasted, while helping ensure occupant satisfaction.
H. J. Enck, LEED-AP, CxAP, is principal and founder of Commissioning & Green Building Solutions, Inc. (CxGBS), an Atlanta, GA, commissioning and green building consulting firm.