Buildings are interconnected arrays of components that are designed to serve a certain purpose.
After the last nail is hammered home, the last screw is tightened down, and the last control panel is set up, the best way to know the components, and the building, will perform as designed is through commissioning the structure.
Commissioning is the process of evaluating the installation and performance of a building’s components and systems and how they work in the context of the entire structure, and then making adjustments or repairs as needed to meet the design specifications. Commissioning can apply to a new build, or to a retrofit, where it’s called retrocommissioning.
According to a report from the Lawrence Berkeley National Laboratory, “commissioning is arguably the single-most cost-effective strategy for reducing energy, costs, and greenhouse gas emissions in buildings today.”
After examining 643 buildings, the researchers found that commissioning for new buildings would cut energy use by 13 per cent and achieve a four-year payback. Existing buildings did better, saving 16 per cent with a one-year payback.
Commissioning also helps designers in right-sizing equipment such as heating and cooling equipment, which can achieve significant up-front cost savings. Those cost savings “routinely offset at least a portion of commissioning costs—fully in some cases,” the report stated.
In addition to energy savings, commissioning offers benefits for occupants and for contractors.
Occupants enjoy increased comfort, better air quality and assurances that issues such as humidity levels and building pressurization problems will be identified and rectified.
Contractors, meanwhile, are less likely to have to deal with complaints or costly litigation as a result of building defects.
Commissioning is essentially quality control, which most professionals take seriously. This additional process is needed because the complexity of interdependent systems, such as the envelope and the HVAC system, leaves room for errors in installation or mistakes in component settings, to cite just one example.
One study of California homes found variances of 50 per cent in air tightness among homes of the same design, built by the same crews, in the same subdivision. Air tightness, of course, will have a substantial spillover effect into energy use, occupant comfort, and air quality.
Commissioning has also come to be seen as an essential risk-management factor that lets home owners and building owners ensure that they get the building performance they expected and paid for. As an element of quality control, the process can identify problems and performance issues that not only don’t meet specifications, but could develop into more serious and costly issues over time, such as a backdrafting ventilation system, for example.
The report lists the most common defects and the cost (US), which include $2.9 billion in costs each year due to duct leakage, $1.9 billion per year due to HVAC being left on when the building is unoccupied and $1.7 billion per year due to lights being left on when not in use.
Though awareness and practice of commissioning is growing, partially due to Green Star and LEED requirements, and particularly in commercials projects, the report finds that many factors contribute to the still-small number of projects that are commissioned. Top factors include:
● Lack of awareness of the process.
● Perceived lack of value for smaller buildings, such as single-family homes.
● Lack of professionalism in the trades.
● Lack of code requirements.