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Part 3: Maintenance, Commissioning Keep BAS Going Strong
By David Callan
April 2014 -
Keeping your BAS in good working order requires ongoing maintenance and commissioning.
6. Once installed, the system must be maintained. BAS rely on sensors to operate. Once they sense something, they respond to the variable, either temperature, humidity, flow rate, status, pressure, or another digital measurement. Therefore, the system only operates efficiently when its sensors are calibrated. The problem is that no one calibrates their sensors. Even when vendors promise calibration on a maintenance contract, it is rarely done. While it is possible for the operating engineer to calibrate them, this skill must be learned and added to the operator's current maintenance regimen. It's critical to be diligent in making sure that all items on the service contract, including calibrated sensors, are executed properly on an annual basis. If not, the incremental cost to upgrade down the road could be much higher because things aren't working or haven't been maintained.
7. To get the best results, commission before and after the BAS installation. One reason it can be intimidating to plan a BAS upgrade is the design-build model of the project, as each contractor sells and installs systems for one or a few manufacturers exclusively. While there are benefits to the single-source responsibility inherent in this model, it can lack objectivity. For even when competitively priced, building automation systems can differ in their services, software, hardware, interface features, and sequences of operation.
An independent energy audit and existing building commissioning can help isolate and identify areas that could be improved with a BAS upgrade. These services will help identify which BAS features will benefit the facility most, based on existing systems, current building operators, local climate, and more, while putting some real numbers to a desired return on investment. Ultimately, obtaining a third party expert opinion can arm the facility manager with knowledge of the facility's needs and requirements and therefore, how to make a real apples-to-apples comparison of BAS options.
Setting realistic expectations up front means that everyone will understand the operational goals of the new or replacement BAS. This knowledge can help craft the appropriate request for proposal (RFP) and allow the facility manager to explore upgrades to supporting equipment, which can be accomplished more cost effectively prior to BAS implementation to substantially increase the benefits of the new automation system. For example, upgrading the VFDs, pumps, air handler, or components of these systems before the implementation will allow the building to get the most benefit from sophisticated algorithms and sequences.
Commissioning the BAS system after it's been installed and the operators have been trained on it will provide the insurance that the time, money, and effort spent on the new implementation has paid off. Because it's easy for something to go wrong with the dampers, actuators, sensors, and overall sequences of operation, testing these areas to make sure the system is programmed correctly and executing functions appropriately can be the difference between a successful implementation and an inefficient new or upgraded BAS.
Remember that a BAS is a computer program with electronic operators doing what a human would otherwise do manually. Therefore, the BAS will only be as good as the equipment it's controlling and the people controlling it. Being a highly effective BAS buyer means understanding this principal and knowing the building and its operators well enough to meet all their needs and operational goals, beginning with the RFP process through installation and future maintenance.
David P. Callan, P.E., HBDP, LEED AP, leads the high performance buildings practice for McGuire Engineers in Chicago, designing LEED certified commercial and institutional buildings, federal buildings, sustainable healthcare facilities, mission critical facilities, and net zero energy buildings.
Part 1: Keep Big Picture In Mind To Ease Challenges Of BAS Upgrades
Part 2: Front-End Interface Is Building Block Of Successful BAS Upgrade
Part 4: Showcase Products: Building Controls