Dr. Andrew Persily is a Fellow at the U.S. National Institute of Standards and Technology (NIST), where he has worked for four decades after earning a Ph.D. in Mechanical and Aerospace Engineering from Princeton University. His research has focused on indoor air quality and ventilation in commercial and residential buildings, including the development and application of measurement techniques to evaluate airflow and indoor air quality performance and of multi-zone airflow and contaminant dispersal models. He has published more than 300 journal articles, conference papers and NIST reports. Dr. Persily was Vice President of ASHRAE from 2007 to 2009 and is past chair of ASHRAE Standard 62.1 (Ventilation for Acceptable Indoor Air Quality) and Standard 189.1 (Design of High-Performance Green Buildings). He is a Fellow of ASHRAE, ASTM and ISIAQ and recipient of the NIST Bronze, Silver and Gold medals.

Meghan McNulty, PE, LEED AP O+M, is a Senior Project Engineer with Servidyne in Atlanta, Ga. Meghan works with building owners and operators to reduce energy and emissions while improving indoor air quality. She specializes in investigating and modeling energy use in existing buildings, assessing ventilation systems and ensuring compliance with local building policies. Meghan is a Registered Professional Engineer in Georgia and LEED AP O+M. She joined Servidyne in 2013 with a Master of Engineering from Virginia Tech and a Bachelor of Science in Mechanical Engineering from Princeton University. Meghan volunteers with ASHRAE on the Government Affairs Committee, Standard Project Committee 62.1, Ventilation and Acceptable Indoor Air Quality, Standard Project Committee 241P, Control of Infectious Aerosols and as chair of Technical Committee 4.3, Ventilation Requirements and Infiltration. In 2019, she received the ASHRAE Government Affairs Award for outstanding effort and achievement in state, provincial and local government activities in connection with technical issues related to the activities of the Society.

ASHRAE Journal:

ASHRAE Journal presents.

Episode 23: Dr. Andrew Persily and Meghan McNulty discuss the disconnects between design intent and performance when ventilating buildings and how ventilation theory and research play out in real world applications.

Andy Persily:

Great to see you, Meghan. I'll look forward to the conversation today. My name's Andy Persily. I'm a mechanical engineer at the National Institute of Standards and Technology where I've been for just over four decades, but who's counting, right? I've done research on building airflow, building air tightness, indoor air quality, both measurement methods and predictive tools. I was going to ask you, Meghan, how you got interested in ventilation, but I'll give you my answer first.

When I started all this stuff, all my work was about air tightness, measuring, building air tightness, measuring infiltration rates, the rate at which air enters buildings from outside independent of the air handler, just driven by weather and a few other things. We installed these tracer gas systems, automated tracer gas systems that would inject tracer, measure the tracer gas to K-rate 24/7 for weeks at a time so we could measure these infiltration rates at night when the system was off.

We did not turn the tracer gas systems off during the day, so we started measuring ventilation rates with the system on and it was like, well, low and behold, they don't agree with the design values. They don't agree with the standards, and they were all over the place. That's kind of how I started with ventilation-ventilation. There's more to that story, but Meghan, what's your story? How'd you get into all this?

Meghan McNulty:

One of my first jobs as an entry level engineer was to support LEED certifications for existing buildings. One of the prerequisites for that program is you have to prove that the building today can comply with ASHRAE Standard 62.1, meet the ventilation rates for acceptable indoor air quality. I was having to work backwards, take this design standard, and apply it to an existing building. I needed to know all of these inputs that are not documented.

We don't know, here's a system that's been running for 20 years and it's been reconfigured and there are different people in the spaces using it differently. It just seemed like a mess. It seems so inexact. So I was interested in, are there trends in this? How did this building come to be? What's the history? Actually, Andy, I was introduced to you by your paper about the history of ASHRAE Standard 62.1 before I even met you. We've been having a ventilation conversation for even longer than you realize. I consider you like the historian of ventilation, you know the whole history. Where did these rates come from? What's the background? How did we get here?

Andy Persily:

I mean, that's a good question. The long answer would take more time than we probably have today, but I will point out in the ASHRAE Journal that just came out a couple days ago, I have a short little column that speaks to that issue about where they came from, but I'm not going to read that column right now. I'll give you the thumbnail version.

When 62-1989 was published, there was a lot of controversy that had to do with smoking and formaldehyde and a whole bunch of other things. ASHRAE realized they better start working on the revision right away. At that point, they weren't on the three-year cycle to match the building codes. They were on no cycle. A new committee was formed in '92, and I was lucky to be put on there. I wasn't all that experienced.

There were all sorts of smart people, researchers, real doctors, fake doctors who had a Ph.D. like me and manufacturers and so on. One of the first tasks was what should the rates be? We looked at all the science. There was a lot of science going back to the 1930s on how people perceived body odor in spaces as a function of the ventilation rate and also as a function of the people and what they were doing. We had that research.

We kind of knew how much area needed to control body odor. There was some more recent research at that time on how much we needed to control the odors from building materials and furnishings. We looked at all that and we talked and debated and argued for hours and hours and hours, even at multiple meetings to basically come up with the table of rates that are in the standard now with some modifications over the years.

I'll note that most of the research was from office studies and office buildings or chambers, but the table of rates covers offices, schools, conference rooms, a million different space types. We had to take the science we knew and it was good science and extrapolate it as best we can using our engineering judgment. That's the term we use, but as you read in the column, and despite what some people say, health was on the table, front and center. We even debated how much air you needed to control airborne infectious disease transmission, and concluded we didn't know enough to set those rates.

There's a lot of misconceptions about the standard and the rates and where they came from. We used the science. We used a practical experience and there were a million different competing points of view that we had to wrestle with. I worked on that and then I got punished by being made chair during that tough time.

Meghan McNulty:

I was going to say, didn't you have an important role in this?

Andy Persily:

It was funny, there was a chair and then our friend and colleague Steve Taylor was made chair. Then, before one of the meetings, Steve came up to me and said, "Andy, they told me I have to have a vice chair. You don't have to do anything. Would you be vice chair?" I said, "Fine. Fine." Little did I know, and little did he know that when he finished his term, I was the logical choice for better or worse.

Meghan McNulty:

That always happens when you say yes to vice chair. It's dangerous.

For that update in the early '90s or even the 1989 version, that was a big change from the prior years, right? The '80s were maybe not the best time for ventilation in buildings.

Andy Persily:

Yeah, I mean the '89 standard was, I'll say, influenced and that's not a bad thing by the realities of the energy crisis or we called it then. Maybe, they overreacted. I don't know, but the big change after '89 was that the committee was directed to write it in mandatory in enforceable language so the codes could more readily adopt it. It's become part of the building codes. That was a big change.

1989 and the previous versions, the first one was in '73, had all sorts of interesting stuff, interesting discussions of contaminants and all sorts of things, and a lot of shoulds starting in the revision that we started in '92, no more shoulds. It had to be shall or must and no more interesting discussions. It just had to have requirements where it was clear what you had to do to comply. It was hopefully clear how they would be enforced. That was the other big change.

Meghan McNulty:

Now, it's a minimum standard. It's the worst possible building you are legally allowed to build, no longer something to aspire to, and yet over time it winds up being that the codes become the target, the codes become the thing we're trying to reach instead of what we're trying to surpass.

Andy Persily:

Right. All the requirements for minimums, anything below the requirements is illegal. If it's adopted in the jurisdiction, people are free to do more, but I think as you implied, sometimes people see it as a maximum. You can't do anymore. That's not the case. I don't know if you have discussions with clients where there's a discussion of increasing the rates, increasing the filter efficiency. Does that ever come up?

Meghan McNulty:

Yes. I think especially in light of the pandemic, there is much more of an awareness, an understanding that indoor air quality is something that's important, that's important to the people in the building. Ventilation is not just a nice-to-have when the weather's nice, but something that needs to be provided all the time. It used to be much harder to make the case that this is an area where we should be sure we're providing ventilation all the time.

Andy Persily:

In these discussions where people realize ventilation's important and they read, they should have more air, I mean, how hard is it to educate them that their system has these capabilities and their climate has this much humidity and you might be able to go up this high, but you're not going to get some of these very, very high rates that some people are suggesting.

Meghan McNulty:

Yeah, I think there is initially just resistance to change. My system can't do that. It won't work. I know that, but when we dig a little deeper and we ask questions about how it was designed, how they operate it throughout the year, we find that there is some flexibility and there are always constraints. I'm trying to find how is this building operating now and what are the ways it can do better and where is that upper limit?

For filtration, we often talk to building operators who are like, "Oh no, I can't take MERV 13 filters. That will never work. Then, we go to the next building and they'd say, "We've been using MERV 13 filters for years. No big deal." We would look and the systems were pretty similar. The filters they were using were pretty similar. When we looked at what the fans were capable of doing, it wasn't a technical problem, it was more of a perception problem or that expectation of better filtration wasn't there. That's something that has really changed.

I think when it comes to ventilation, outdoor air is seen as sometimes this scary expensive thing and a scary expensive thing that will bring in all this terrible moisture and destroy the building. It's often seen in its negative. Yes, it can have too much moisture. Yes, it does take money and energy to condition it, but at times, it doesn't. It doesn't take much money or energy to condition it, and it's actually the kind of temperature and humidity that we want in this space. Thinking beyond just that worst summer day, there's some flexibility.

Andy Persily:

I mean, in these discussions, I'll call it a pandemic motivated changes to systems, I think, part of me, I often say every building and system is unique, and I don't know if everyone is super unique, but you need to understand the system and how it was designed and its capabilities before you—I mean, as you've gotten a lot of experience, I guess that's not necessarily a ton of work, but it's essential, right?

Meghan McNulty:

Yeah. Step one is, well, what do we even have here? Often, the system I'm looking at, the base building system is designed in one year, and then the distribution has been changed three other times, and then the tenant installed some system and now it's a hodgepodge of all different systems that never really considered each other operating together. We do have to just kind of benchmark where are we and how do these systems interact?

I was visiting a building where they had a daycare center. It was an office building. One area was a daycare center, and daycares, if you look in Standard 62.1, they require more ventilation air than an office space. You have smaller people who are more active and more things going on. They need more air.

Andy Persily:

Art projects, aquariums, all sorts of craziness.

Meghan McNulty:

Snack time, much more fun than the office building and the daycare and the office space next to it, they had the same outdoor air intake serving these two units we were going to measure. How much outdoor air is going to each one? We're doing this baseline assessment and I stick the anemometer into the duct and, okay, that's a reasonable number, but notice that the air that I'm feeling is nice, cold, and this is the summertime in Florida. It shouldn't be that temperature. It should be hot and humid.

It turned out that instead of outdoor air going to the daycare and the office, daycare air was going to the office and not really anything was coming in from out of doors. No one knew. How long had this been going on? Not sure, but we were able to fix it, but that baseline understanding, if we're talking about what ventilation rates should I achieve, well, is the system working just at baseline to do what it is supposed to do?

Andy Persily:

I often make the point, and I'm sure you do as well, maybe adjusting the ventilation rates up or down or whatever that might have merit, but first is the system operating as intended. Are the ducts connected? Are the dampers functional and all that? Do that first before you get into some of these. I don't know if the amount of outdoor air is a fine point, but if the system basically isn't functional, you shouldn't be messing around with the rates, right?

Meghan McNulty:

Yeah, like zero outdoor air versus some outdoor air, that's a huge improvement compared to some and some plus 5% or then getting into marginal gains there.

Andy Persily:

If you go into buildings and you poke around and crawl around and talk to people, you can't help but learn some interesting things. You've done a lot of these walkthroughs, crawl-throughs, right?

Meghan McNulty:

Yeah.

Andy Persily:

I mean, what are some of the things you've learned in addition to the ones you just mentioned?

Meghan McNulty:

Everything breaks and everything can break and everything will break. It's just a matter of when. I think the expectation that it was designed and installed and now it runs and it's perfect, is just not true. I think about my car. Things break on it, and that's a standardized piece of equipment that's mass produced, and we're working with one of a kind, kind of complex machines that require a lot of human intervention.

To think that everything will operate perfectly from day one and just keep on going that way, seems unrealistic, but yet people kind of get upset when you say, "This isn't working right." I think instead of being upset, it's, well, "Hey, great, good catch. Now, we can fix this and make this better."

Andy Persily:

I mean, it's all about operations and maintenance or O&M, and that shouldn't just improve your ventilation and indoor air quality, it's probably going to make your building more energy efficient because if the ventilation system is screwed up, the controls, whatever it is, what the heating and cooling is probably out of whack too, that's going to break also. That's going to save money and make the building more comfortable, right?

Meghan McNulty:

You've looked at the EPA’s BASE study, and that's a big database of building information. What years and what types of buildings was that looking at? What does that information tell us?

Andy Persily:

For the listeners who don't know, the EPA BASE study building assessment, and I don't remember what the S is, an evaluation, look it up, EPA BASE. It was a study of 100 randomly selected office spaces in the country. Part of the motivation was, this was kind of around late '80s. Everybody was stressed about sick building syndrome and we knew about the buildings that had high levels of complaints. We didn't know about, so-called normal buildings.

A complaint building, everyone had a headache or 50% of the people had a headache in the afternoon. Well, what do you see normally? Is that high or low? They went to these 100 office spaces. I will note that the first planning meeting for the BASE study was the first trip I took after my daughter was born and now she's designing HVAC systems in Colorado. We sat around and we came up with a protocol. I developed or took the lead on the protocol for evaluating and inspecting the systems and the spaces and the ventilation assessment. That's all written up.

I think one of the interesting things is as part of the evaluation, they had to write down the design minimum alter air intake. Well, in half the buildings they couldn't find it. I think they looked. I think it wasn't there. Was it out of date? If they could find it, I suspect so. These building inspections and the measurements were in the mid-'90s. They couldn't find the fan specs. Back then they were on paper. I did some work in buildings where if you really looked and got a short ladder and climbed on top of the air handler, you might see the fan specs all rolled up and covered with dust but—

Meghan McNulty:

Oh yes, I know that.

Andy Persily:

Yeah, but I think in some cases they were just had been tossed or something. In some buildings, they had them really well, easy to find. Everything was in nice shape. I often generalized back then that the cleaner the mechanical room, the more likely the ventilation rates were in line with design, right? Because somebody was spending some time on things. We learned that 50% of the buildings, the minimum outdoor air design value was not available.

A lot of the buildings were below the design value. I can't remember that percentage, but if you look at the data, a lot of them were above because of the economizer cycle. Awful lot of people out there, I'm not talking about the general public, I'm talking about indoor air quality research and other people who really think they might be interested in ventilation, don't even know that economizers are common, where the outdoor air intake goes way up and presumably when the air is clean and dry, unless the sensors are out of calibration, then, you don't know when they're going to open up the dampers, right? I'm sure you've seen that in, you're not in the friendliest climate for economizer operation in the summer, right?

Meghan McNulty:

Well, depends if your system's large enough. In the summer, sure. July, no, but here in Atlanta, the shoulder season's very nice. Even now in April there's pollen. Ideally, you've got some filters to take care of that component, but temperature wise, economizer mode is great right now. In a lot of places now, it's even required. The energy efficiency standards and codes require that. If you're only focused on the minimum ventilation rate at December and July, you're missing a big chunk of the picture because it varies throughout the year.

Andy Persily:

I guess if the system's well controlled, it can run economizer in the morning when it's cool and then go to minimum later on when it gets hot.

Meghan McNulty:

Yeah, I think that approach of being dynamic and responding to conditions instead of set it and forget it, will work a lot better. That's how you can get energy efficiency and indoor air quality to be friends instead of enemies like a lot of people think they are, but I think they can work together.

Andy Persily:

A lot of people think it's an inherent conflict, energy efficiency and indoor air quality. I guess it is if you have a very narrow view of things, but there's more to life than ventilation, even though that's what we're talking about today. As I did this research and measuring ventilation rates and buildings, I learned about this thing called controls, right? That's really important. It was a little bit beyond me. I was involved a study in the '80s of 8 federal buildings around the US where they were using more energy than somebody expected, and I don't know where their expectations came from.

That's where we were measuring infiltration rates and ventilation rates and some of the systems, there were a lot of pneumatic controls. I guess, maybe they were starting to do digital controls in the '80s, I don't know, but there was one building where there was a knob for outdoor intake, and I forget the name of the building operator. He would turn that knob and he'd go across the street and have a cup of coffee and a piece of pie, and then he'd come back an hour later and see how things were running. It was totally manual and he gave it some time to adjust.

Meghan McNulty:

Controls may have advanced, but I've still seen the control for an outdoor air damper as the crowbar in someone's hand. There are great capabilities of digital control and actuators and automatically adjusting, but there is still a lot of a human element. Those buildings from the '80s, they're probably still around. A big chunk of the buildings that are going to be here in 2050 when we need to decarbonize, we already have them. Maybe they need something a little more advanced than the crowbar or the knob.

Andy Persily:

I think I know the answer to this. I mean, I'm sure you've seen lots of situations where there's a sophisticated, and I don't know if I want to say high tech, but advanced control system that's been disabled by the human operators because they didn't understand it or they just couldn't get it to work right.

Meghan McNulty:

It's in theory, this kind of complex control scheme is great. Everything is optimized, but the operator interaction isn't optimized. It's not clear what's going on. If there's a little bit of a glitch, then we can't use it. It has to work all the time. Sometimes, I think, something that's simple and reliable, even if it doesn't capture every last kilowatt hour of energy efficiency, if it's going to work most of the time, that's a better way to go.

Andy Persily:

As engineers, I mean, we love high tech stuff, right?

Meghan McNulty:

Of course.

Andy Persily:

We love innovative things. They're cool, but whenever I hear about some new gizmo or new whatever it is that's going to be used in buildings, I always say, "Who's going to take care of it? Who's going to maintain it when we don't maintain the low tech stuff?" As you said earlier, there's nothing that won't break or go out of whack at some point. I always ask that question.

Meghan McNulty:

One gizmo I do want to talk about is CO₂ sensors. Whenever I hear CO₂ readings, I think, "Uh oh, we need to bring Andy into this," because there has been a lot of misunderstandings and misinterpretations of the readings, of CO₂ readings in indoor spaces. I have right here a little handheld CO₂ meter that I'll carry around with me and try to interpret what it means, but what are your thoughts on using CO₂ indoors and having a lot of sensors to read CO₂?

Andy Persily:

Well, it's a tool and as they say that the youngster with a hammer and not everything's a nail, that misinterpretation goes back a long time. I wrote a paper in '97 kind of trying to speak to that. What does it mean? What does it tell you? What does it not tell you? I don't think it's had much impact and I've given talks and so on, but now that we're seeing these consumer grade sensors proliferate, a lot more measurements, a lot more interest, probably a lot more misinterpretation, I don't know what to necessarily to do with that.

As I talked about tracer gas techniques earlier, the CO₂ omitted by people is essentially a tracer gas. You can analyze the mass balance and back out ventilation rates, even if they're very approximate, but you need to understand the assumptions and the theory and do the math correctly and all that. That's fine perhaps for a researcher or something, but a teacher in a classroom or somebody putting one in their house, that's not a reasonable expectation. What do they do and how do they learn something useful?

I mean, there's a couple things. One is don't breathe on it. The air that you exhale is 30, 40,000 ppms. If that thing is too close for you, you're going to get an elevated reading, but that's probably not the biggest problem. It's what do you compare it to? Your meter was reading 850, and I know people who would look at that and freak out and they'd go, "My gosh, it's 850. I'm going to run outside and call 911." I don't know what the right number is. I think it really depends. I know it depends on the space, the number of occupants, what they're doing and what ventilation rate you want.

There's not a single ventilation rate. You can follow the standard. You can follow the recommendation that some smart person put out on the web. If you're using CO₂ to verify the ventilation rate, what's the rate you're trying to verify? What's going on in the space in terms of occupants and when are you measuring it? If you measure it five minutes after people show up, it's not going to have gone up very high. You need to think about those things, which is probably more complex and more detailed than the consumer necessarily needs to hear or a homeowner necessarily needs to hear.

We developed an online CO₂ tool that allows you, or an online tool that allows you to calculate the CO₂ level you might expect in a space given the occupancy and giving the target ventilation rate from Standard 62.1 or Standard 62.2, but you can change all those inputs. Meghan and I put together a little list of articles and things that people might want to look at, and you can read about that there.

Meghan McNulty:

I think that CO₂ calculator that handles all the math for you is so great, because I once tried to do the calculation by hand and well, unit conversions and all sorts of things, I gave up, but you have this calculator that spits out, here's what you would expect to see at steady state for that geometry, that number of people, how active they are. I really like that gives you a graph of not just what you're going to get in the end compared to another value, but how things change over time. That's been really helpful.

For me, to put it in more realistic numbers, it's going to take seven hours of this many people in this space to get this high. If I'm using a CO₂ meter to judge, is outdoor air enough in this space, yes or no? It's not going to know until the end of the workday when everyone leaves. That's not going to work.

Andy Persily:

How many spaces are occupied continuously for seven hours? Not a lot. People take breaks, go to lunch or whatever. You kind of have to deal with the occupancy you have and figure out the timing of all this. I'm glad you found that useful. Is that something you show, ever show owners or operators, or is that kind of more than they want to know?

Meghan McNulty:

I think that's more than they want to know, but I use it with my colleagues when we're planning out site visits, and especially now with a lot of office buildings have lower occupancy than they used to. If we have indoor air quality readings from the past 10 years, and we routinely measured say, 800 to 1,000 parts per million in the space when the ventilation system was working, well, now they're half as many people. What ballpark should we expect? If we're still getting those numbers from before, but they're half as many people now, maybe something's worth investigating a little more, but maybe everything's fine.

Andy Persily:

Yeah, and if you have half as many people, can you dial back the outdoor air? Especially early in the pandemic, people were talking about, we need more outdoor air per person. Well, there's two ways to do it. One is to bring in more air and the other is to have less persons. You have the same amount of outdoor air, but you're dividing it by 50% of the occupants. All of a sudden, you've doubled the CFM per person.

Earlier on, you noted that most buildings of the future exist today, but our standards, they're about new building design and the kind of code process, the regulatory process sort of disengages after the certificate of occupancy is granted. What do we do about existing buildings? I know that's kind of where you spend your workday, right?

Meghan McNulty:

That's such a good question. Buildings are really unregulated. Once the keys are turned over, you can kind of do whatever you want, sadly, except your elevator needs to be inspected and the fire marshal has a final say, but other than that, there's not a whole lot and not a whole lot of requirements.

There are some interesting trends in regulations for existing buildings for energy efficiency and carbon emissions, and a lot of jurisdictions have building performance standards, and ASHRAE also has a standard for building performance standard, Standard 100, but in these jurisdictions, they're saying, "Regardless of when your building was built, here is our expectation for your energy efficiency or your carbon emissions. If you aren't there by this date, then what are you doing to improve? You need to show us that you did an energy audit or that you've implemented some projects."

New York, Washington D.C., Seattle, Washington State, everyone's got a slightly different twist on how they're doing it, but I think what will come of that is we'll maybe learn a little more about how to make sure that ventilation gets included. Some of those programs do explicitly say part of your energy audit, make sure the ventilation system is functioning and doing what it needs to do.

Andy Persily:

There are some, I'll call them, more aware building owners who see the connection between good indoor air quality and occupant satisfaction and occupant performance, and they have the budgets to do it right, and they really keep an eye on things and they don't need to be regulated, because they're doing it anyway.

There's all these, I'll say, buildings more on the neglected end of the scale who don't have those budgets. You can think of school systems who aren't as well financed as others, or public housing or all sorts of places where there's just not a lot of money to do things right and keep things going. I often think about the neglected buildings. I don't know what we do for them, but that's not an engineering issue. That's a societal, economic issue that we're not qualified to address, I guess.

Meghan McNulty:

I think the fact that it is technically feasible, we can fix these buildings. We can provide that perspective so that people don't say, "This is impossible. This building can never be fixed." There might be, but for most buildings, what they have can be improved a little bit. I think for most buildings, it's not going to mean they need an entirely new system.

Andy Persily:

It doesn't have to cost a fortune to do this, to get things back in order.

Meghan McNulty:

Yeah.

Andy Persily:

Somebody has to pay for it, whether it's the owner or the local jurisdiction or whatever. It's a tough one, but it's not impossible.

Meghan McNulty:

My colleagues and I, we used ASHRAE's Epidemic Task Force resources and applied it to a lot of our clients' buildings to help make sure that they were meeting those recommendations. Is your ventilation system working? Can you upgrade your filters to MERV 13? A host of other items and we found that at first pass, a little less than half the buildings were providing the right amount of ventilation, and then another third could easily get there without too much cost or effort. It's just some of that basic operations and maintenance fixes.

Combined, that's 75% of buildings should be able right now to provide the minimum ventilation rate, or they just need a little bit of work. Of course, there are some that are going to need a little bit more work, but a majority of our buildings just need a little bit of elbow grease to get where they need to be.

Andy Persily:

Well, that's encouraging. After people listening to this might have thought we just had a bunch of bad news, but that's some good news. Something you said earlier reminded me that my mother's last job before she retired was a facility manager.

Meghan McNulty:

Really?

Andy Persily:

I asked her, "Well, what about indoor air quality? Is that a issue for you?" She said, "Well, sometimes, but the big issues are the elevator that isn't working, the room that has to be locked, where the lock is broken," and all these kind of mundane, it maybe isn't the right word, but immediate fires that have to get put out, and they don't have a lot of time and extra bandwidth to deal with indoor air quality.

When I've given general indoor air quality talks, I make the point, there's a lot of things that can give you headaches at 3:00 in the afternoon. Yes, it can be an air contaminant, but it can be stress at work, it can be daycare challenges at home. It can be all sorts of things can make you feel crummy in the afternoon, that isn't necessarily the air.

Meghan McNulty:

That's a good point about all of the demands on an operator's time. I'm coming into a building and I'm laser focused on two things, indoor air quality and energy efficiency. I don't need to worry about the locks. I'm not really focused on the fire system or the special event that tenants are holding. Having someone come in and just focus on those issues and then distill what's the key thing that needs to be fixed or is everything kind of okay? I think that really helps because there are a lot of things on their plate.

Andy Persily:

Meghan, you just made a great point about building operators and the different demands and their time, while we've talked about buildings that might not be operated very well, there's a lot of really smart, conscientious building operators out there who really want to do the right thing and work very hard at it.

When I was doing research studies in office buildings primarily, I met a lot of really excellent folks who are operating buildings, I often observed that the really good ones got kicked upstairs into management positions and weren't operating the building anymore, which was really a shame because they knew they had little sticky notes and the sequence of operations, and they knew the ins and outs and they had that building running right, but they were so bright that they made them wear a tie and you never saw them again.

Meghan McNulty:

It's funny you say that. The last site visit I was on, the operator actually was on vacation. We had a scheduling mishap. Instead, someone who was more senior from the region was assigned to walk me around, and he used to be the operator at that building. He is very familiar with all the systems. The first thing we do, we look at the control systems and we find out, three of the six units, outdoor air dampers are not open or reading zero CFM, or it doesn't appear to be communicating. I didn't have to do anything. Immediately, he was like, "That is not good. This is not right. Let me go talk to people."

We saw his colleagues later and he was like, "Hey, what do you know about the outdoor air dampers? Those have to be open. This is for people's health." I was just, "Ugh." My heart was so warmed. I was so excited. We had a great visit just sharing ideas. I'm glad that he has that regional position because then he can share that knowledge with everyone else that he works with, but yeah, there are some great operators out there.

Andy Persily:

Studying the plans, doing computer simulations, all that stuff might provide some insight, but there's nothing like talking to the people in the building, whether it's the occupants or the operators, and because you're going to learn things that are never been written down. I was involved in a building. It was one of these sick building syndrome situations from the '80s or '90s, and I can't remember what the problem was, but we could not figure it out.

We looked and we poked around and talked to people and couldn't figure it out until one day because of some vacation schedule, the guy who operated the building at night was working the day shift, and I had never met him before. I asked him, "What's the deal with this?" He goes, "Yeah, yeah, every night at 8:00 I do this," or whatever it was. No one on the day shift knew what the deal was. He knew and he happened to be there. Then, that solved the problem.

Another little story that I'm sure you've experienced, we would install these elaborate air sampling systems as part of our research studies, and it would require us to go for all the different mechanical rooms. We really, our life was much easier when we got a master key, but nobody wants to give you a master key, but when they saw you crawling around and covered with dust and working your tail off, they would like, "That's like a real person. Here's the key." You develop some credibility by showing that you're a hard worker and willing to get your hands dirty, right?

Meghan McNulty:

Mm-hmm.

Andy Persily:

You run into that?

Meghan McNulty:

Yeah, I'm invested in solving this problem, even if that means I'm now covered in dust and I found a dead lizard and all kinds of things.

Andy Persily:

What's some of the favorite things you've found above a suspended ceiling when you were poking around a building?

Meghan McNulty:

A donut box.

Andy Persily:

Any donuts?

Meghan McNulty:

I didn't look.

Andy Persily:

Okay. I mean, it's a great place to find flashlights, tools and all sorts of things, but it's a little risky to just reach your hands up there and feel around because it might not be pleasant, right?

Meghan McNulty:

Yeah. You want a good headlamp, for sure.

Andy Persily:

Yeah. Meghan, I just remembered this great article you wrote in the ASHRAE Journal last year. You were looking at some older buildings. I mean, old is relative like '80s, '90s, vintage or something. Can you help me remember?

Meghan McNulty:

My colleagues and I were looking at buildings from the 1980s that were designed probably to that older version of 62 of the very low ventilation rates after the energy crisis. We were doing a feasibility study of what would it take to meet today's ventilation rates? How do we bring this whole building up to today?

These systems were about 30 years old. It's kind of time to update, replace anyway, and we found these issues because we were looking at Epidemic Task Force guidance applied to these buildings, and they wanted to be able to tell their tenants, "Hey, yeah, we meet ASHRAE Standards." Then, we found out, oh, no, you don't. How do we fix this? Because every building is its own unique situation, it was complex.

There were a lot of factors. We had to take into account how equipment was configured and how much tenant space could be intruded upon by more equipment. We had these two buildings, and once we looked at our decision making process, we realized there were commonalities. We could kind of create a process to follow, to figure out what options would work, whether you're going to put in one new central system or you're going to have distributed systems or distributed adjustments to systems throughout. Then, what's the cost?

At the end of the day, the owners, they wanted to know cost and construction schedule, the details of the mechanical systems. Yeah, yeah, that's fine, but what's it going to cost and do I have to bother my tenants or can this be done without anyone realizing it? Those were two big factors, but I think the big takeaway is that it is possible to retrofit buildings instead of saying, "No, we can never get there." We should be saying, "Well, how? How can we bring buildings up to the latest standard of 62.1? What are our options?"

Andy Persily:

How can we not do it, responsibly, not bring them up to where they're supposed to be?

Meghan McNulty:

Right.

Andy Persily:

This whole process, I mean, you have it. It's in your head. It's in the head of your colleagues. I mean, could that ever be developed into some, I don't know, elaborate flow chart, measure this, look at this, and then go to step 15 or we don't want to put you out of a job?

Meghan McNulty:

That's what we tried to do. Here, let's evaluate the cooling capacity of the central plant, evaluate the cooling capacity of the air handler. Just so many different steps, so many different things to think through. If you need to increase the air coming in, what are you doing about the air going out? Is the toilet exhaust system sized appropriately for this new version? There are just so many components. We tried to capture everything. If someone else is doing this, they can replicate this process or at least point to this and say, "Did I hit some of the same major points that they did?"

Andy Persily:

That makes sense. I used to, or I still do, but I would get questions from colleagues in the research field. They're doing a study of these schools or whatever buildings and indoor air quality study, and they ask me, "How do I measure ventilation?" I used to sort of wing it and say, "It depends."

Now, I say, "Well, let's sit down and talk about it and get a piece of paper and tell me about your building. Tell me about your systems, and maybe I can help you figure out how to measure ventilation." You've got to understand what's going on before you can understand what's going on, right?

Meghan McNulty:

What do you think are some of the trends in research that are going to be really helpful going forward?

Andy Persily:

I mean, I think there's more research all the time that's focusing on the people and how they react both physiologically and psychologically to different features of a space. I mean, that's important. I mean, it's all about the occupants, right? Buildings don't exist to have low utility bills that you can brag about. They exist for people to work or learn or heal or have a good time. It's all about the people, about the occupants.

Meghan McNulty:

Right. I think that's the hardest part, is the people component. We know physics and psychrometrics, and we can do all kinds of math equations, but people are a huge variable.

ASHRAE Journal:

The ASHRAE Journal podcast team is managing editor, Kelly Barraza; producer and associate editor, Chadd Jones; assistant editor, Kaitlyn Baich; associate editor, Tani Palefski and technical editor, Rebecca Matyasovski. Copyright ASHRAE. The views expressed in this podcast are those of individuals only and not of ASHRAE, its sponsors or advertisers. Please refer to ashrae.org/podcast for the full disclaimer.