Hey folks, Phil Zito here and welcome back. In this post, we're going to be talking about working with test and balance. We're going to cover what test and balance is, how you work with them, what you need to be aware of, the different types and levels of work that you could be doing with them, and a bunch of other stuff.
Test and balance, what is it? Well, the “what it is,” is in the name. It's testing to make sure systems are performing according to their design parameters, and then balancing out those unperforming aspects of the systems.
Now, this primarily has to do with airside and hydronic systems. So, when you think about a central utility plant, you think about a chiller. That chiller has a tonnage capacity, ton of cooling capacity. It distributes that ton of cooling capacity via gallons per minute waterflow. This water flows throughout the building, it goes into coils, and goes through valves to get to these coils. At the end of the day, these coils then absorb the BTU’s from the air stream and transfer them into the chilled water return which then flows back to the chiller, and either gets released into the atmosphere via radiator plates or via a cooling tower, if it's water cooled chiller.
Alright, so pretty straightforward how central utility plants work. Well, how do we know that these coils are getting the right water flow? How do we know that the valves aren't being starved or aren't demanding too much water? How do we know that the pumps are flowing? How do we know that the temperatures are accurate? How do we know all of this information?
Well, then you cascade that down to airflow. How do we know that our VAV boxes are supplying the right amount of air out the diffusers, and that they're at the right mins and maxes for their box size? How do you know? Well, how, is through test and balance.
The Test and Balance folks are going to typically be another contractor. Although, I have seen building automation companies do test and balance themselves. I, myself have used test and balance devices to do test amounts on hydronic and airside systems. Normally, you are trained and certified as a test and balance person do it. In my case, this was service, so we were just using this to get a measurement of existing sites and understand if they were they out of whack or not within performance standards.
So, Test and Balance is going to come up with a test and balance plan, and this is going to sound very familiar when we get into our next post, which is commissioning agents, where we're going to hear about a commissioning plan. So, Test and Balance is going to come up with a plan and they are going to execute this plan. The level of support you are required to give is going to typically be in either Section One or Section Three of the specification. It is going to say, “You need to provide this level of support. You need to give 16 hours of support. You need to allocate 2 people and they need to have walkie talkies to talk to one another. You need to provide the tools so that the test and balance person can log into your system and actually calibrate things.”
So, there's a variety of levels of required support, and that's going to vary from contract to contract. I've seen some where, you literally have to dedicate someone to walk around with a Test and Balance person all the time. Then I've seen others where you just set up the graphics, with the parameters for tuning your CFM, tuning your flow, your set points, etc, and then once you have those graphics set, you just hand it off to Test and Balance and give them maybe four hours of training, and they're off to the races.
Now, one way is not necessarily better than the other, although I do prefer creating some graphics training tests and balance for a couple hours and letting them have at it. The thing is that if you don't understand what way you're required to support test and balance, this can lead to not properly scheduling your projects, this can lead to mis-estimates and labor, etc. So test and balance, support and commissioning support are two of the big areas that I see newer estimators miss out on from a pricing perspective, and newer project managers miss out on from a scheduling perspective.
So, at the end of the day, it's going to come down to you figuring out:
- What test and balance support do I need to provide?
- How do I need to provide it?
- How much do I need to provide?
- When do I need to provide it?
If you can answer those four questions, you're going to be well prepared. Supporting test and balance is not going to be difficult. At the end of the day, there's only so many things we're going to have to change and those are going to be our CFM’s on our airside systems, our duct static pressure setpoint on our air side systems, our building static pressure, and potentially changing some of the rotation of our valves and actuators. If those things were improperly installed, test and balance usually will catch that and will request that be fixed.
Not too bad. Not like what we're going to see when we talk about commissioning agents in the next post. Commissioning is where you can lose a lot of money. If you don't properly manage expectations, especially if you have full total commissioning with an owner's rep, yeah, that can get real nasty. You can end up dumping six figures worth of labor into a project that you did not properly estimate for.
So, test and balance at the end of the day, the sole purpose of it is just to make sure that water is flowing where it's supposed to flow, air is flowing where it's supposed to flow, and in the right amounts. If you keep that in mind, and you understand the kind of systems thinking
Shorter post, but I mean, there's really not that much more to say about test and balance. I'm sure test and balance folks would argue that there's a lot to say, but we're looking at it from a building automation perspective.
Thanks a ton and take care.
