E5: COVID-19 and Ventilation Systems in Buildings

Prof. William Bahnfleth is a Professor of Architectural Engineering, at the Pennsylvania State University in University Park, Pennsylvania. He is also chair of the newly formed ASHRAE Epidemic Task Force. Previously, he was a senior consultant for ZBA, Inc. in Cincinnati, OH and a principal investigator at the U.S. Army Construction Engineering Research Laboratory in Champaign, IL. He holds bachelor’s, master’s, and doctoral degrees in Mechanical Engineering from the University of Illinois, where he also earned a Bachelor of Music degree in instrumental performance. His is a registered professional engineer.

Emily Starr is a Senior Project Manager with KCI Technologies in Mechanicsburg, Pennsylvania. She earned a Bachelor of Architectural Engineering from the Pennsylvania State University, University Park, PA and has worked as a consulting engineer for the last twenty years. She is a professional engineer, LEED Accredited Professional and a Certified Passive House Consultant. She currently serves as co-chair of USGBC Central Pennsylvania’s Market Leadership Advisory Board.

Warehaus:

Hello, everyone! I’m Matt Falvey. Today’s episode will focus on the potential impact that the COVID-19 will have on building design, ventilation and other building systems. Today we have both a co-host and a very special guest. Our co-host today is Emily Starr. Emily is a senior project manager with KCI Technologies in Mechanicsburg, Pennsylvania. She earned a Bachelor of Architectural Engineering degree from the Pennsylvania State University and has worked as a consulting engineer for the last 20 years. She is a professional engineer, a LEED Accredited Professional and a certified passive House consultant. She currently serves as co-chair of USGBC Central Pennsylvania’s Market Leadership Advisory Board. KCI is a 100 percent employee owned engineering, planning and construction firm focused on creating a more interconnected, livable world operating out of more than 50 offices nationwide. Their team of seventeen hundred plus professionals offers technical expertise and facilities, transportation, resource management, public works, telecommunications and utilities. So, Emily, welcome. I’m going to turn the mike over to you and you take it from here.

Emily Starr:

Thank you, Matt. I’m pleased today to introduce Dr. William Bahnfleth, Professor of Architectural Engineering, and Director of the Indoor Environment Center at the Pennsylvania State University in University Park, Pennsylvania. He is also chair of the newly formed ASHRAE Epidemic Task Force. As a former student of his at Penn State, I’m excited about this opportunity to talk with him today. Prof. Bahnfleth, welcome! I thought we would start off by having you tell the audience a little bit about yourself and what led you to engineering.

Prof. Bahnfleth:

Certainly humbling! Glad to be here. I’m a mechanical engineer by training. I went to the University of Illinois and worked for the Corps of Engineers and a construction research lab and then also a consulting engineer for five years in Cincinnati, Ohio. Since then, I’ve been at Penn State in the architectural engineering department for almost 26 years now. I started out, like many mechanical engineers, with a strong interest in energy efficiency in buildings because I came up through the University system in the 80s and 70s.

But around 2000, I had a graduate student who had heard about the potential damage that could be caused by epidemic disease. And he came to Penn State to get APHC. And I was one of the biggest buyers and it really changed my entire career direction. So, for about the last 20 years, I’ve mainly been working on indoor air quality, and a lot of that work has been directed at controlling infection risk in buildings, using ventilation and filtration, and particularly Terma Site Ultraviolet light.

Emily Starr:

So early on in that 20-year interest in indoor air quality, we had the attack on September 11^th, 2000. Can you tell me a little bit about what happened in your life then?

Prof. Bahnfleth:

Yes, certainly. It wasn’t specifically the attack on the Twin Towers, but whether by coincidence or intent – you may remember – that there were bioterrorism incidents shortly after, where anthrax was mailed to a number of buildings. Some of them were U.S. government buildings. Some of them were private buildings, like a newspaper office in Florida. So, there was a tremendous interest in making buildings safer places to be, in case there was either intentional or accidental, chemical or biological pathogen release. So, we did a lot of research at that time, that was directed towards protecting buildings under those circumstances. But really, a lot of the guidance that we developed is pretty applicable to making buildings resilient when something like an epidemic disease comes around.

Emily Starr:

That’s interesting! So, given the current COVID-19 pandemic, in what way do you see the way in which we ventilate buildings and the required standards changing?

Prof. Bahnfleth:

Well, if we go beyond just the amount of outside air we bring in, there are a number of things. But of course, that’s maybe the place to start. We need to look at ventilation standards from the point of view of how much outside air we really need to dilute and remove contaminants inside of buildings? The air quantities that are required under the standards that apply to commercial and residential buildings are based on protecting people from infectious diseases. Really only the standards that apply in healthcare facilities do that. So perhaps more getting more outside air in our systems. I think another thing that would be a concern is air filtration. Again, in most buildings we have pretty low standards for filtration. The system that is used in the United States uses a rating system called MERV – Minimum Efficiency Reporting Value. And the larger the number, the more efficient the filter is, particularly at smaller particle sizes. Right now, we’re putting MERV 6 filters into buildings that comply with the residential standard that ASHRAE produces, and MERV 8 into other buildings. And if you look at ASHRAE Standard-170 – the healthcare standard for spaces in healthcare facilities where infection risk is really a concern, its MERV 13 and MERV 14, which does a good job of getting fine particulate matter – P.M. 2.5 – people may recognize that name. So that’s air filtration.

We’ll probably also pay more attention to airflow patterns in buildings. I think the idea of having air flow from clean to less clean, and not the other way around is a concept that’s very familiar in healthcare. But I don’t think we worry about it too much in most other types of buildings. And that may change as well. Those are a few of the things. And I suppose the other thing I would add on is, maybe more use of air cleaners beyond filters. So, I mentioned ultraviolet disinfection as being one of them. There are other technologies that I think are emerging and may be used in the future as well.

Emily Starr:

Do you think we’ll be able to find a good balance between the amount of outside air required to do this and not have the energy it requires to condition outside air? That’s always a struggle.

Warehaus:

I think I think that’s a big challenge. The cost of energy associated with providing better air quality and just energy use as a sustainability issue is an important one. And I have a certain amount of confidence that that if we really make it a goal to improve the air quality and safety of people in buildings relative to airborne hazards, that we will wind up coming up with ways to do that in a way that does not really increase the energy use of a building.

And the example I can give of that is that, many years ago when we became concerned about ozone depletion, I was hired through the company that I was working for at the time to do calculations for the Department of Energy about how much additional energy chillers would consume – air conditioning systems – when replacement refrigerants that would not deplete the ozone were put into them. And so, we did those calculations based on what we knew at the time. And a few years later, all the manufacturers were producing equipment that was much more efficient. So, I think it’s a problem that can be solved, although we may not exactly see how we’re going to do it right now.

Emily Starr:

Okay. Do you see changes in other building systems related to the response to COVID-19?

Prof. Bahnfleth:

Well, besides the HVAC, maybe not so much. Well, I think architecture, I guess – to get to the point – is probably where things might change. You’ve probably read a lot about the possibility of opening windows as one way of getting more outside air. And a lot of buildings don’t have operable windows. And there are a lot of good things about being able to bring in outside air when you can? I can imagine changes to architecture that make it easier to have people occupy a building without having high risk of infection. I read in a draft article that I saw just yesterday, about an architect talking about more use of stairs because of the density of people on stairways is much lower than it is in an elevator. So, if we think through all the ways that buildings create opportunities to transmit disease, there are going to be a lot of ways that we can probably make changes that would reduce that risk.

Emily Starr:

And with all of those things, we come back to balance, of course. Opening a window will decrease the effectiveness of your air conditioning system, which is a struggle many of us have dealt with over the years in buildings with operable windows. And I’m hoping that people becoming more aware of all these factors because of the pandemic, maybe we can come to better agreement on how all these things should work.

Prof. Bahnfleth:

I think that’s true, of course. Opening windows sounds great as a way of bringing more outside air in. But it can totally disrupt the pressure relationships that you may have designed into a building. So, if you open windows on two sides of a building, you may be getting a lot more outside here. And but then again, you may be pushing air from a space where there’s an infected person into a space where there’s someone who is susceptible. So, there are a lot of relationships or other relationships between these different measures that have been proposed that need to be considered, and simply naively applying them could be risky. When you consider major operational changes, they need to be evaluated by someone who’s competent to do it.

Emily Starr:

Yeah. So, these are certainly challenging times, but sometimes good things come out of hardship. We’ve talked a little bit about it, but do you see any pros in this context?

Prof. Bahnfleth:

Well, I hate to say it, but this is an event that has really focused people’s attention on the importance of indoor environmental quality in a way that nothing has for a long time, if ever. One of the problems of improving indoor environmental quality (IEQ) in buildings is that, it’s a lot harder to measure the benefits, or the costs of poor IEQ on the other side, than it is to measure how much energy your building is using, and how much it costs. But we like to talk about it in my area of expertise, that the 1-10-100 rule – a dollar of design cost turns into ten dollars of operating cost – that the building and the people in it are contributing one hundred dollars of operating costs. So, the value of people’s health and productivity far outweighs a little bit of additional construction cost to put in better systems or design a building to have better indoor environmental quality. They certainly outweigh, if we calculate them accurately, the cost of the resources that operate the building.

Emily Starr:

Yeah, I would hope that having workers either shut down or working from home for a month to six weeks now would open the eyes of some of the people who pay for these things. It’s easy for me as a consulting engineer or as you just said, that these things are good, but we’re not paying for them. So, I hope that it’s really been brought home to some people.

Prof. Bahnfleth:

I think it’s incumbent on those who are promoting this notion that we can do a lot better with indoor air quality in particular to demonstrate the value of it. It’s not so easy to do. There’s been some research, but I think we need to do more so that the case is really made for that.

Emily Starr:

Do you see any possible cons coming out of the situation?

Prof. Bahnfleth:

Well, I think the psychological ones are probably the worst. I think that the fact that people really wonder whether it’s safe to be in a building that they used to never think about is disturbing. And it’s going to take quite a while, I would think, for us to recover from that fear and to really feel that our buildings are the good environments to live and work in, that we normally think that they are.

Emily Starr:

Now, last question for you has to do with the ASHRAE epidemic task force that you’ve been recently asked to chair. Can you tell us a little bit about what you guys are going to work on with that? I know you haven’t had a lot of time to come to conclusions, but what are your goals or what is it focused on?

Prof. Bahnfleth:

Yeah, certainly. Of course, organizations like ASHRAE that deal with HVAC, the building design and operations, have been asked to make recommendations about what people should do to make themselves safer in their buildings. So, I was asked to put together a team for ASHRAE and I did. We have a bunch of really great experts in a variety of areas from practice, from research, from government. And we really have three main tasks that we’re working on right now. One of them is to produce guidance that can be used today to help make people safer where they are. And the main types of facilities that we’ve focused on – because of people being shut out of work and school – have been home (residential buildings) and health care facilities in particular as well as how to expand the capacity of healthcare facilities, the so-called surge capacity. So that’s the short term. And the measures that you recommend in the short term really require making the best of what you have.

We’re expecting to – in a month or months – to start re-occupying buildings, and then the focus shifts to ‘how do we make these buildings safe for re-occupying?’. How do we make sure that a building that may have been shut down for months is ready for re-occupation? That’s kind of the middle ground. And then the longer range task is to think about what needs to change in guidance, in standards so that we have buildings that are better prepared the next time something like this comes around, so that we don’t suffer the kind of pain and disruption that we have in the COVI-19 pandemic. And that will probably mean bringing the idea of infection control somewhat into non-health care facilities, and also thinking about resilience for buildings in a way that we haven’t before, and putting things like capability to respond to something like a pandemic into the thinking that goes into designing the systems for a building, not just how it’s going to operate normally.

Emily Starr:

This has been very informative and insightful. I can’t thank you enough for joining us for this. Before we sign off, Matt, do you have anything you’d like to ask Prof. Bahnfleth that the audience might be interested in?

Warehaus:

Yeah, this is great! Bill, thanks again so much for your time. Very insightful. I guess the thing that I’d like to ask, obviously, since I work for a firm full of architects is, how do you see this pandemic potentially changing the design of higher education buildings like lecture halls, theaters, dorms? Do you think there’s going to be anything unique in that space that perhaps you didn’t discuss with Emily?

Prof. Bahnfleth:

I certainly think that we’ll be looking at higher ventilation rates, perhaps, in those spaces when they’re occupied, and perhaps different ways of delivering air that would tend to remove contaminants. So, perhaps, spaces will be less likely to have mixing ventilation systems that are going to distribute pathogens throughout a densely occupied space, and maybe more of a displacement approach to move them up and out of the occupied zone. So, I could imagine things like that as well. And I certainly expect, as a result of this for standards, for particulate filtration to go to higher levels and possibly more encouragement to use air cleaners, partly as a way to not have to increase ventilation quantities as much as we would otherwise have to, which would be quite expensive and energy intensive.

Warehaus:

Yeah, interesting. We also talked with an MEP engineer about the potential use of ultraviolet light sources outside of the health care setting, which we know certainly that could come into play as well for sure.

Prof. Bahnfleth:

Another thing is, making buildings as no touch as much as possible. There are so many things you have to touch in a building on a regular basis – the elevator buttons and all sorts of things. To the extent that we can get that kind of the equipment out of buildings, may be better. Maybe occupancy sensors instead of light switches, all sorts of things you can think about when you start to ….

Warehaus:

Yeah, that’s great! Great point. Well, that’s pretty much everything I wanted to ask. Prof. Bahnfleth, I can’t thank you enough. This is really great, Emily! Great job co-hosting. I can’t wait to go back in and listen to this and push it out to our audience and certainly open it up so you can push it out to yours as well. So, barring anything else from any one, everyone have a great rest of the day, and I look forward to seeing everyone once we come out of this quarantine.

Prof. Bahnfleth:

My pleasure.