What is building commissioning?
What exactly is commissioning? ASHRAE defines the Commissioning Process as “A quality-oriented process for achieving, verifying, and documenting that the performance of facilities, systems, and assemblies meets defined objectives and criteria.” In other words, the goal of commissioning is to make certain that what was installed is what was intended and operates accordingly to meet the Owner’s needs.
With that definition in place, let’s took at exactly where commissioning came from to fully understand what it is and what it is intended to do. The commissioning process started with the Navy for new ships being constructed prior to being placed into service. The ship’s engineering plant, weapons systems, living quarters, electrical systems, structure, and such are installed and tested. During this process of testing, the new ship undergoes stationary and sea trials during which deficiencies needing correction are discovered and corrected.
The Navy and the ship’s Captain and Crew wanted to be sure that all the systems and components of the new ship were working properly during testing, rather than discovering problems while in service or combat. According to the Navy History website, depending on the size and complexity of the ship, this commissioning process could take as long as 20 days for a World War II landing ship to as long as 3 years for a nuclear-powered aircraft carrier.
How does this translate into today’s buildings? Well, just like the Navy’s ships, today’s buildings are becoming more and more complex while trying to meet ever increasing demands for efficiency. Digital building automation systems are utilized in most commercial buildings to operate just about every aspect of the facility. With the increase in complexity of the building and components, particularly HVAC components, you as the Owner want to be sure that everything is working as intended to meet your operational needs. The process of commissioning as taken from the Navy can be applied to your building. We verify that all the equipment and systems are installed to meet the design intent and manufacturer’s needs as well as thoroughly test everything to ensure that they operate as intended. One important thing to point out is during this testing process, or functional testing, not only do we want to test things on a point-to-point level, but as whole building systems as well. It is important that we test and verify that systems interact with each other properly and don’t fight each other.
One example of this is to make sure that we don’t have simultaneous heating and cooling taking place. While there are certain instances where this is designed to happen, such as for dehumidification purposes in an air handling unit, we typically don’t want a unit to heat and cool at the same time. It uses energy that is not required, which costs you, as the Owner money.
Diving a little bit deeper, what is the importance of including commissioning into a project, especially when the stakes typically aren’t as high as those a Naval ship may encounter? What value can it bring? Fair question – here are some benefits:
Reduced change orders. One study of six new construction projects found that commissioning reduced change orders by 87% and contractor callbacks by 90%, thus reducing the total construction cost by an estimated 4% to 9%.*
Reduced utility costs. When HVAC equipment isn’t operating correctly it consumes more energy: when air handling units have to run longer to try to heat or cool spaces, or don’t shut off during scheduled unoccupied times, or even when outside air dampers in air handling units bring into much outside air. All of these items will have a significant impact on your energy usage. Industry sources indicate that on average the operating costs of commissioned buildings range between 8% and 20% below those of non-commissioned buildings.**
Fewer occupant complaints.
Fewer equipment failures such as freezing coils in air handling units because outside air dampers weren’t properly controlled, or pumps cavitating because of improperly installed valves downstream.
Less wasted time and money chasing problems, any problems found are easier and cheaper to correct while the contractors are already on-site.
I have mainly focused on the mechanical HVAC side of a building during this post; however, commissioning can also be applied for the building envelope (doors, windows, roof, insulation, moisture/air barriers, etc.) and electrical components and systems as well. Commissioning any and all of these systems can bring value to a project.
*Joy Altwies, “Information from a Commissioning Process Case History,” power point presentation to Energy 2002, Palm Springs, CA.
**www.gsa.gov website on Cost-Benefit Analysis for Commissioning.