Seven Ways to Improve your Commissioning Functional Performance Testing
Functional performance testing (FPT) is the bread and butter of the commissioning process. These tests serve as a final check of building systems to make sure they meet the owner’s needs.
Below are some ways we have found to make our functional performance testing more effective:
1. Use Sampling Wisely. For some buildings, such as mission-critical facilities, testing 100% of equipment may be necessary. However, non-life-safety or otherwise non-critical, redundant systems can often be successfully tested using sampling. For instance, VAV boxes can often be easily tested using sampling, such as 30% of boxes. We will typically do a “deep dive” into a random sample of boxes, using physical step-by-step testing. If the initial sample passes the test criteria, we follow this up with batch testing for the remaining boxes. For example, we will throw all of the remaining boxes into full heat and watch whether the resulting discharge air temperatures behave as expected, since a faulty heating water valve would be unique to a particular box.
2. Build Great Relationships with the Contractor. While there are certainly some shady contractors out there, the majority I have worked with have been competent and genuinely care about doing a good job. Some ways that I have found to improve the process include:
Create a collaborative environment, rather than simply finding faults and assigning blame.
Recommend specific and reasonable solutions for every deficiency found.
Communicate often, and clearly.
Resolve issues at the lowest level possible (i.e. subcontractor > contractor > architect > owner).
3. Speed Up Your Network. On some jobsites, the building automation system (BAS) interface can be painfully slow. For instance, on a large wireless network or a legacy system, you may find yourself watching the spinning wheel on the BAS screen more than doing actual testing. Fortunately, we can often speed things up by paying more attention to the network itself. Some examples I’ve seen that can drastically reduce delays include:
Plug directly into the local equipment controller for testing when possible
Ensure that there are no “0,0,0” addresses for any unit controllers on the network
Make sure that there are enough repeaters on a wireless mesh network
Check that there are not too many devices on the link.
Temporarily override default equipment delays, i.e. from 5 min to 1 min.
Though network issues are not usually part of the commissioning engineer’s expertise, working with the contractor to address any BAS network performance issues upfront can shave many hours or even days off of the commissioning schedule and help you better meet the owner’s schedule.
4. Prioritize your Testing. When creating the commissioning plan, identify critical pieces of equipment and also consider which systems are most prone to failure. Proportion your testing time accordingly. For instance, you might choose to commission the chiller or boiler plant first, and spend a greater amount of time on these systems as they affect multiple systems downstream.
5. Be Smart about the Construction Schedule. Start your functional performance testing process early enough to meet the owner’s move-in target date, but late enough that subcontractors are actually fully done with their install and start-up. Otherwise, you may end up identifying a lot of issues that they simply hadn’t had time to finish yet, wasting time and slowing down the overall schedule. For projects with an aggressive schedule, consider providing preliminary testing by sampling a few key pieces of equipment to identify any common deficiencies before installation is complete, and to let the contractor know what to expect during functional testing.
6. Organize your Tools. Make a short checklist of the tools you will need each day, i.e. temperature probes, hard hat / vest, RH meter, manometer, multitool, laptop, power cord, etc. Many of my jobsites are fairly remote, and it’s a long drive back if you forget something important. A couple of other items I’ve found useful are extra batteries, and occasionally a small table and chair.
7. Use Trending Aggressively. Set up BAS point trends as soon as point-to-point testing is complete. Trends are ideal for observing equipment behavior over time, such as for testing morning warmup or cooldown sequences. Some other sequences where trending can be particularly helpful include:
Reset sequences, such as duct static pressure or discharge air temperature (watch the setpoint reset over time)
Occupied/unoccupied changeover and associated outside air damper operation (especially optimized start/stop)
Economizer sequences
Observing space temperature versus space temperature setpoint for a large number of unique spaces
Data analytics also has great potential to help interpret trend data even faster. Smart commissioning providers and engineers will leverage technology to provide better service to their clients, while still relying on proven commissioning processes and common sense to deliver solid results.
