We’ve already talked about the five biggest benefits of commissioning (Cx), and we’ve also explored why Cx is still an emerging strategy with the potential to be a competitive differentiator. By now you may feel a little more confident in taking the plunge into creating your own Cx practice. But there’s one more unknown to resolve before you can dive in:
What does an effective, proven Cx regimen actually look like?
To answer that, in this post I summarise one of our white papers that details the five steps you should take when you conduct new building commissioning (NBCx), retrocommissioning (RCx), or recommissioning (ReCx). In addition, I’ve included a quick overview of monitor-based commissioning (MBCx), an up-and-coming analytics-based strategy that’s changing the way many building owners and managers are approaching Cx.
Commission early and often
Let’s get one thing straight: Cx should be applied long before the first brick of your building is ever laid, and well after you finish its construction.
It may seem strange to commission when your building doesn’t exist yet. But during the lengthy, complex planning and design process, you can very easily and quickly lose track of the original relationships between subsystems and your standards for energy efficiency. This initial stage of Cx is process-driven, in that it’s mostly a matter of checking your designs against your requirements.
Once your building is built and occupied, you’ll want to continue with Cx because even best-in-class systems cannot perform at optimal level forever — you need to continually check your real-time performance against your design requirements.
Let’s get technical, technical
Want specifics? Here’s how a step-by-step process of NBCx, ReCx, and RCx should look, according to our white paper.
- As I mentioned before, get your Cx agent or third-party involved as early as possible in the process. Give them all the designs, system documentation, performance guidelines, and other information that will help them understand your goals and realities.
- Your Cx agent will then develop a plan of action based on clearly identified objectives and timelines. These objectives are critical to determining the success of the Cx exercise. If your Cx agent is not directly conducting systems testing, the agent will identify control sequences for testing purposes. During this stage your agent will also validate that the systems are commissioned and objectives are met.
- Next, your Cx agent will carry out equipment testing in two stages: pre-functional performance testing and functional performance testing. In any commissioning project, your agent will first do a pre-functional, point-to-point validation of your systems. Then, the agent will shift focus to functional performance testing, checking that your systems and equipment are finely calibrated.
- What is pre-functional performance testing?
In this stage, your Cx agent tests all the equipment — controls, hardware, software, sensors, and controlled devices — on a stand-alone basis. This process ensures that the right equipment is installed in the right place with proper naming and tagging. Your agent would also conduct continuity testing and voltage checks in your cabling.
- Functional Performance Testing
Once your systems are tested for stand-alone performance, they are then tested for integrated performance. Your Cx agent will determine whether the response is aligned correctly, run operation sequences to test the system’s responses, and check trends, critical alarms call outs, remote dial up, access, and passwords. The key goal here is to successfully demonstrate that the Building Management System (BMS) and HVAC are operating correctly together.
- After your Cx agent tests your systems and equipment, you’ll get a report on the findings for final sign-off. Your report should include the tests performed, results obtained, issues identified, and possible solutions offered. You and the Cx agent would then sit down with this report and determine which CapEx measures possess the most significant savings or reliability potential.
- An integral, though often overlooked part of Cx is to carry out post-occupancy seasonal testing. You and your Cx agent should set up a schedule to monitor your building’s operation, analyse its short-term trend data from the BMS, and developing an understanding of all issues faced by the building’s occupants and owners over different seasonal conditions.
Where ongoing Cx fits in
Monitor-based commissioning, an emerging trend, uses software analytics and sensors to ensure continual monitoring. Many of the world’s most efficient, cost-effective buildings use MBCx because continual monitoring and fine-tuning makes for continual energy savings.
The graph below illustrates this concept. With recommissioning, many building owners allow their systems to fall out of alignment over the course of many years, allowing inefficiencies to creep in like weeds, with only occasional maintenance. With MBCx, you use your BMS to identify these weeds, and your Cx agent to “pull them out.” The result? You’ll make fruitful business decisions and harvest bigger savings over the long run.
I know we’ve only scratched the surface — there’s a lot more to talk about. Feel free to leave any questions or comments below, and check out our Cx white paper for the complete picture.