Hey folks, Phil Zito here and welcome back. In this post, we're going to be exploring Guideline 36. I've had a lot of customers, both on the owner and the contractor side, reach out to us lately asking us to create an energy management, a measurement and verification, systems optimization, and an energy conservation measure course and training materials.
This is the first step in course creation, like anything we do here at Smart Buildings Academy, we always want to understand at a deep level what we are going to be communicating with our audience. This starts with a learning process. So, what you're seeing right now, what I'm sharing with you and inviting you into right now is the process I go through every time that I research anything prior to bringing it within our company and deploying it through our training organization.
So, I have a decent understanding of what Guideline 36 is, specifically Guideline 36-2021 version. That being said, you can always know more. What I'm going to be taking you through is how do you learn more? How do you take all of this information, especially technical information, and how do you digest it, make it make sense and then actually make it useful?
So, when I first started to unpack this topic of Guideline 36, the first thing I had to do was get up to date on the 2021 version because I was dealing with the 2016 version the last time I went and read something on it. The first thing I ever do, when I'm looking up a topic is to go to Google search, type in the topic and I type in file type:PDF. What that does is it pulls all of the PDF-based information related to that topic. So, in the case of Guideline 36, it's going to pull any presentations that anyone's done, it's going to pull links to the read only standard of Guideline 36, it's going to give me a slew of information. That is kind of the first step, just finding the information so that I can even digest it.
Another way I like to narrow that down, is I'll not only do Guideline 36 file type:PDF, I'll also do site:edu or site:org. That will pull all the documents from orgs as well as edu sites. So, not only will I get the presentations, but I’ll also get white papers, a lot of research papers, things like that. So, I can start to get multiple different angles. If you've ever read a standard or guideline, it can be very difficult to figure out how to take this guideline and then translate that guideline into action, and that therein lies the rub.
Guideline 36, while having a lot of really cool information in it and sequences that I rather agree with, it can be difficult to consume it and figure out how to apply it. So, my hope is that by going through this process, you'll come out of here better prepared to consume any technical information and apply it within your day to day tasks.
So, the first thing I start with after I have some decent resources to read up on is I ask myself questions related to what I'm trying to do, and that's going to influence how I look at this documentation. It’s going to influence how I consume this documentation. So, there's a couple frame of reference questions that I could look at and utilize in order to learn this information.
The first question I could do if I'm an engineer is:
- How do I translate this into mechanical design?
- How do I translate this into system sizing?
- How do I translate this into specification language?
So, having those questions is going to shape when I go into guideline 36, for instance, and it talks about trim and response, or it talks about fault detection, or it talks about zone group control, things like that. These are things that I can consider now, in my sequencing. These are things that I consider in my SOP, and I can start to piece these together.
Another angle I may look at, and this is a very common angle, is from a programmer or a service technician perspective. So, as a programmer, I may be wondering to myself:
- How do I go about actually programming these sequences?
- How do I go about implementing these sequences? What do I do? What can I do?
So, that's another angle that I will take on this, okay. In the service tech angle, I may be looking at:
- How do I survey a site looking for potential retrofit opportunities or upgrade opportunities for my customers? How do I do that?
Alright, so with all that being said, let's start to dive through Guideline 36. I'm going to bounce around in perspectives, I'm going to take an engineering perspective, I'm going to take a programming perspective, and then a service tech perspective.
Alright, Guideline 36 is a guideline, it is not a standard. So unlike, ASHRAE 55, ASHRAE 62.1, ASHRAE 90.1, these are not standards, these are guidelines. Now, these guidelines definitely can impact the standards, so, we need to be cognizant of that. We need to understand that the guideline can impact the standard, but unlike a standard where you'll have, for example, 62.1, it'll say I think it's like 1000 square feet or greater, or some sort of CFM setting, you then have to implement DCV, demand control ventilation. Unlike that, this is a guideline that you can pick and choose what you want to do.
Let's dive into its objectives. The objectives are energy cost reduction, and we'll see that in trim and response. We'll see that in, for example, how we run PID loops. We'll see that in how we do things like looking at head pressure on chillers, how do we do things like managing lift, etc. There's also engineering cost reduction, project coordination, system uptime, those kind of three buckets. If you can get everyone around a guideline sequence and you implement it, then you'll see with a lot of OEMs, they are currently implementing specific sequences and specific logic to those sequences, and those sequences are Guideline 36 sequences in some cases. So, it can get everyone kind of on the same page.
It can assist you in IAQ, indoor air quality. I will say this guideline, from my experience, is more focused on energy cost reduction, facility optimization, and runtime optimization than it is on IAQ. You can hit a lot of IAQ goals just straight off through ASHRAE 62.1, and then do enhanced ventilation, if you need to, based off all the COVID guidelines.
There's a scope of air side and hydronic side. This guideline is broken up into what is a standard format, for a lot of ASHRAE guidelines, which is you know, a forward talking about the intent as well as who was involved. The purpose of the guideline, as I mentioned, it's focused on HVAC energy efficiency and performance and control stability. We'll see control stability come across in some of the PID loop sequencing and some of the trim and response sequencing. We'll also see, which I really like, tying things like the control loops to the enable states.
Now, since this information is copyrighted, I can’t provide any screen shots. I can’t even read the actual text word for word, but I can share my pure interpretation. I'll provide links to some of the resources we find so you can digest those on your own, but I'm going to respect everyone's copyrights and not share anything here.
Alright, so as I mentioned, the scope it goes through, what is the scope of this guideline? It's to define points, which will be important when we talk about the FDD side of things, the fault detection side of things, as well as the enhanced alarming. It also defines functional tests and it defines sequences.
Now, the set points, even me being a fairly technical person, it was a little difficult to initially digest this due to the equations and the nature of the equations in here, so do be cognizant that these set points are largely for engineering. So, when you do look at the set point portion of this and you're wondering while looking at an equation, what the heck does any of this mean? Do realize that that is meant for engineers, or people who are going and building system sizes.
I am of the mind that controls technicians should not be designing set points. Anytime you select set points, and you're not test and balance, and you're not engineers, you then absorb the liability and responsibility associated with setpoint selection and system sizing. So, that usually should be done by the engineer, because we all know everything is controls fault, and always is, and we don't need to add anything else that could be our fault. Like I said, there are a lot of set points and design parameters.
They talk about zones and boxes. Zone groups is a new addition, a concept you may not be aware of. The premise is you have a group of zones. A zone is not necessarily a space, a zone is basically a single process loop. So, temperature, zone temperature control, that process loop, that is a zone. Some folks will design zones as spaces, some of them will define them as an area serving a specific population, like, this is a classroom, or this is an auditorium, and then that auditorium may be split into multiple zones.
So, zone is something that is kind of defined, but then it can also be open for interpretation. They talk about things like dual docked VAVs, I'm not going to dive into that. Single fan, single zone VAVs, chilled water, hot water, and fan coil units. It's pretty cool. They also go into some TAB stuff, and they go into information figured out by the controls contractor. So, they talk about how you go and find things like your controllable minimum, how do figure out your set points, and how you determine what points you should have.
If you're looking for guidelines, and that's exactly what this is, on how to go about designing and implementing a control system, there's a lot you can take from this. I've run into a lot of people who talk down Guideline 36 saying it can't work in their area because of maybe the enhanced outside air, or maybe the trim and response, or maybe they don't have the data point density. My caution to you, as you look at the guideline, is not to throw out the baby with the bathwater. Take what you can from it, utilize the guideline as just that, a guideline for system design, realizing that you may not and probably should not use everything in this guideline.
So, they come up to a part where they list out the points. So, at this point, we've talked about the scope, we've talked about set points and design parameters which is more for the engineer. Now we're moving into lists of points where it'll say this point’s required, this point’s not required. This becomes really cool. I like this portion of the guideline. As maybe an owner who's trying to self-execute controls, or maybe a controls contractor who's trying to get more precise by templating their designs, this provides a really good guiding point. This provides a really good guiding point for creating your templates and creating your standards.
If I were a controls submittal design manager, and I was realizing that my submittal designs were getting rejected due to lack of standardization, and if I was looking at my costs, and they weren't decreasing every project on my submittal costs to a point, I would say that I should probably look at standardizing common things like spaces, air handlers, fan coil units, etc. This guideline helps you do that. It provides standards on points to the point where it says this is the device type you should have, this is what should be required, and this is optional. So, you can build out a pretty robust point library and control stencil library that you can then automate through macros and things like that, using this guideline. So that's pretty nice. Like I said, when we get to the sequence of operations, there's going to be a lot of information there. You can pick and choose what you want to use, and by picking and choosing what you want to use, you then can take the control diagrams, you can take the sequences, and you can really build out a pretty templated library that you could then automate and use in your organization.
So, list of points, I'm not going to read those, obviously. Sequence of operations. Now, this is where things get a little bit interesting, because there's a huge general section and then there are some generic things related to ventilation zones, thermal zones, groups, etc. Then they get into the sequences. So, this is where if I am an engineer, or a programmer, or a service person, I can take benefit from all these and even as an owner operator. As an owner operator, there's some stuff here in the initial section five that I could look at and say that this is going to make my facility more efficient. These are relatively low effort, software changes, or hardware changes that you could create a checklist that would have an impact. So, pretty basic stuff that then you can implement.
Moving on from there, into the other areas of ventilation, thermal zones, etc. This is where we get into things like the trim and response, which has been around awhile, we get into alarm suppression, time brace suppression, valve averaging, all sorts of stuff. But in a nutshell, this should not feel as intimidating to you as a lot of folks think it is. If I look at Guideline 36, the big changes are trim and response, zone grouping and zone averaging, setpoint adjustment on the fly, time-based ventilation, and then some of the plant sequencing and how we go about sequencing plants, how we go about sequencing our condenser side of our plants to better take advantage of those head pressure and lift concepts.
So, as I look through these sequences, a lot of these sequences are just basically the same as anything else you've implemented. The big difference I see is in the addition of new points, the addition of logic that dynamically adjusts set points, the way that alarming is done, and the addition of commissioning recommendations and commissioning points that are built into the system. So, up to this point, we've got a list of points, we've got new setpoints and calculations associated with those set points for our systems. Now we're adding in a little bit more dynamically adjusting sequencing. We're also adding in clear alarming that is tied to system operation, and we're adding in testing and commissioning overrides that are built into the software itself or graphics. So, those are some interesting things that get added in. Then obviously, we have like zone requests and stuff like that, that feed back into trim and response sequencing.
As we continue to move through the system types and move now on to systems like air handlers, we're seeing more clarification of a mode-based sequencing, which is my preferred way of actually sequencing systems in general. If you've ever watched any of our programming videos, if you've ever heard been through our programming course, you know that we teach from a mode-based methodology. Some folks will call it state-based control, and state-based or mode-based control, really, it's going to help to reduce waste through things like simultaneous heating and cooling, things like inefficient mode settings, things like running the system, especially if you're not doing warm up or setback modes. So, morning warm up, nighttime setback, those kinds of things, these are modes that can be implemented. I believe they're going to become increasingly more important as our electrical demand costs and our natural gas consumption costs increase.
We're going to see the use of cooling in the non-peak hours to preload the building, things like ice storage, etc. We're also going to see a more judicious use of heating. So, having specific mode-based control, I believe, will give a facility operator more granular control of how they are able to sequence their building dynamically in order to load shed, reduce utility consumption, etc.
From there, we move on to things like multi-zone units, single zone VAV units. In the VAV units, we see the addition of some sequencing around trim and response, and trim and response can work both on the pressure side of things for air pressure, as well as on the setpoints. Oftentimes, we'll approach our air handling systems from the perspective of, if it's a VAV air handler, we're going to vary airflow, but we're never going to mess with temperature. But with this new sequence, we can see where we have specific temperature set points, we have specific air flow set points, and we have pressure and temperature resets based on actual load within the space. How you calculate load varies. You can get as granular as actual BTU load calculations, or you can simply use call for cooling, call for heating, stuff like that.
Additionally, this is where we start to see in these units, the recommendations of fault detection. It gives a good idea on fault detection algorithms that can be implemented and utilized. It gives an idea on kind of how to go about implementing alarming, implementing fault detection, and once again, testing, and also, we'll start to see some direct tie to requesting of plant. So, hydronic plant utilization requests.
One of the things I really like about this is that it ties the alarms to the system operation. It also ties the modes to the system operation. I've seen way too many times in my career, I've actually been asked to step on a consultancy basis quite a few times to resolve out of control alarms. You know, we wrote a great article on dealing with out-of-control alarms, and that gets us quite a few consulting requests to come in and figure out an alarm situation because it’s out of control.
I like the fact that they have tied these alarms to operations of systems. That is, in my opinion and in my experience, the most common way alarms get out of control. They're not tied to system operation. The system’s off, yet a pressure or a temperature alarm is triggering because the process variable is not being satisfied, even though the system is not occupied and not running. So, that's good to see.
We're going to take a look now at the concepts of chilled water systems, hot water systems and fan coil units. So, the hydronic side, it does a lot to the hydronic systems. If you have been considering optimizing your hydronic plant, but you don't want to invest potentially in plant software and major changes, pending if you have the points and the systems in order to implement these sequences, they are not terribly difficult to implement, even on a retrofit perspective. They have things on plant resets, pump pressure resets, bypass for minimum flow, things like that, head pressure control, temperature overrides, etc.
All of these once again, are assuming that you have the point density. That's why I said earlier, it's really neat the points list they provide you. It gives a good guiding point for folks who want to improve something. So, if I'm in your shoes, and I want to improve something first I'm going to ask, what am I trying to improve? Am I trying to improve energy? Am I trying to improve reliability? Am I trying to optimize systems performance, wear and tear?
Based on those, I start at the sequence, I look at the chunks of the sequence that are going to enable, like a reset. That's going to give you less mechanical wear and tear because you're going to do less load on your system. It's also going to save energy. So, I would start at that, and then maybe I'd see what systems I needed to execute that. I would back into my points that I need to implement that, and then I could put a plan together to either self-execute or have someone else execute based on that information. So, kind of working backwards from my goal, maybe it’s energy, maybe it’s mechanical wear and tear, operational efficiency, whatever. Then I can back into that. That's on the existing system side. On a new system side, once again, starting with understanding the owner’s goal, as well as understanding any compliance you may have with local regulations, and then design accordingly.
Okay, so central utility plant, relatively straightforward sequence. Things like enabling/disabling plants, enabling our system for reset, enabling our system based on requests. So, we see a cascading request structure in Guideline 36 in that zones can request, and zones can actually be put into zone groups which can be like, this group’s in a cooling mode, this group's in the heating mode. That actually is a very interesting way of approaching reducing demand on an airside system as well as on the central utility plant. You start with zone requests; the zone requests drive the trim and response at the airside systems and then the airside systems have plant requests. Those can drive you know, resets of the plant. So, you see this kind of cascading effect.
Overall, Guideline 36, I've been happy with it. I'm really happy to see they added hydronic systems to it, because I felt like that was something that was missing, and now they've added that. Additionally, I like the fact that they give representative controls diagrams. So, if you're a consulting engineer, and you're looking for a way to differentiate your drawings, this is one way that you can do it to provide more value. If you are a designer at a controls contractor, and you're sitting there thinking how you’re going to create a design library, this is a way to create a design library to be able to use associated sequences, points lists, and system references.
Like I said, don't just say, “I'm not going to implement FDD’s, so I'm not going to do Guideline 36”, or, “I can't do this economizer side, it gets too cold outside, I'm going to be freezing coils,” or “I can't do this reset, because I don't have a variable speed chiller, I only have a single set speed chiller.” There's a variety of things you can do, and if I'm to give you any coaching with this, it would be to look at it as a modular guideline that you can implement from sequence back to points if you're an existing building, or from points to sequence if you're a new building.
I got a question from a student asking if there was anything I think Guideline 36 missed, either missed opportunities for common conservation strategies that aren't included or measures that are included that I don't recommend. Well, as I look at the exhaust fan, I would like to see more building pressure control. I've been into too many buildings that are negative or positive static. So, I would like to see more clear direction on static pressure control. I would like to see an implementation guide, kind of like a roadmap, that says “if you are here, do this”. The guidelines try to be everything for everyone, but it assumes that you can step in and take a clear direction.
One of the big, huge things that I think you could very easily miss is I think it's page 40 where they start to talk about control loops, and they talk about PID loops. If you're not paying specific attention, I think you can easily miss where they talk about not using derivative. I've gotten into so many arguments with people in this industry about derivative and PID loops and how I don't believe it's needed. It was meant for industrial processes that run in nanoseconds, it was meant to basically add predictability, and outside of a few lab customers, I don't see the reason for derivative. I think you could easily miss that if you were reading because there's 292 pages right now and the one I'm reading, I think you could so easily miss that, and that is very impactful.
I cannot tell you, as a training organization, as well as a former technician, and Operations Manager, how many callbacks have occurred because of poorly tuned loops. I tell all of our students, and this is a freebie, if you get proportional right on a PID Loop, you're like 98% likely that the loop is going to be tuned. The majority of the time a loop is tuned wrong is when people get the throttling range and the sensor span wrong, and because of that, they get the wrong value for a proportional value on a PID loop. Thus, they set the initial base setting, if you know, proportional integral derivative loop equation, the base setting for that is error x proportional band. So, if you get proportional band wrong, everything else is going to be skewed. So, I liked that they called that out in this, that's very good, but at the same time, I could easily see people missing that.
If you have questions about this topic, please be sure to comment below or send us a message. I love answering your questions. If you’d like to check out Guideline 36 for yourself, have at it. So, thanks a ton, and all of you take care.
