Third Party or Design Engineer: Choosing a System Commissioning Strategy
September 9, 2015 | John Stephens, Mechanical Engineer
Once you’ve built your heat and power systems, it’s important to verify your systems are working correctly. Engaging a system commissioning agent does just that. In the course of system commissioning, an agent will perform a series of systematic checks and verifications of your components to ensure that they are installed and performing per the contract documents. The commissioning agent will also ensure that any deficiencies are clearly documented and resolved to the owner’s satisfaction.
It’s important to understand that the commissioning agent is working for the owner. The process needs to be highly visible to the owner as it proceeds. If there are problems or defects in a system’s workmanship, or functional performance, the owner needs to know this immediately.
A commissioning agent will examine a variety of mechanisms: air handling units, VAV boxes, central plant equipment like chillers, boilers, cooling towers, and pumps – all of this will be verified and validated through Prefunctional (or Static) Checklists and Functional Performance Testing. The most significant component of building commissioning is usually temperature control system, which constitutes roughly about 70% of the commissioning effort.
When performed properly, all of this represents a fantastic value to the owner. To be an effective agent, you have to apply a great deal of theoretical engineering knowledge, in combination with practical experience bringing to the process a deep understanding of the system. When you have that combination of skills, you can go back and discuss issues with the engineer and explore optimizations – applying engineering knowledge, and troubleshooting skills to the project rather than simply checking off mechanisms that work or don’t work. I have always found that “trouble shooting” or the “problem solving” aspect of the commissioning process to be very rewarding. It feels good to be a part of solving challenging problems, and turning over a system to the owner that is functioning efficiently and reliably.
When I perform a commissioning, I record as much data as possible, including factors such as flow rates and pressures, temperatures, and any unusual characteristics of the system. When I find problems, I try to come up with solutions. I don’t implement the changes – but I can speak with the engineer of record, and the owner and suggest potential solutions. Systematic checks, and functional performance testing are at the very core of being a good commissioning agent.
Third party or design engineer
When an owner is ready to engage a system commissioner, the question becomes whether they should use an outside agent or a design engineer who is part of the project. In theory, the commissioning agent is working for the owner in either case, and it shouldn’t change the process much either way. But there are advantages and disadvantages to both approaches.
When commissioning their own project, an internal agent knows how the team works, understands the project from the outset, and has a preexisting rapport with the design engineer. These are significant advantages. But on the other hand, an internal agent may unknowingly be “wired” to expect certain results, or look at the systems from a certain perspective, missing opportunities that someone else might identify.
A third party agent brings a completely new pair of eyes and a fresh outlook, delivering a truly independent perspective. But this agent won’t have as much in-depth knowledge going in, or the same rapport with the team.
So the right approach depends on the project. One way of looking at the question is considering the complexity of the project. If the project in question is very detailed and complex – a renovation of a central plant, say – it may be advantageous to use a design engineer for their preexisting familiarity with the project. For a brand new building, on the other hand, it may be most useful to bring the independent perspective of a third party.
Moving forward with confidence
An agent isn’t on the project to direct contractors. They verify and record, and ideally they should provide useful information for the road ahead.
In my work as a commissioning agent, I put a great deal of emphasis on the final report. I try to create a document that is useful to the owner, including specific recommendations and nuances in the system. Typically I include screenshots of the control systems and sequence of operations: information that will help the facilities group when they operate the building.
As a commissioner, you interface with many different parties who want many different things. But as long as you remember that you’re working for the owner and that every element of the process needs to be visible to them – successes and failures — you can create a great value.
When owners consider the respective advantages of design engineers and third parties, and take care to engage an agent dedicated to delivering useful, forward-looking perspective, they can move forward with increased confidence.