ASHRAE Journal:
ASHRAE Journal presents:
Drew Champlin:
Hey, everybody. Just want to welcome you guys. This is the ASHRAE Journal Podcast recording here at AHR Expo in Orlando. Some 60,000 people are here, and I can't promise that they're all here watching this podcast recording, but we got three great guests here to talk about IAQ and indoor air quality and wildfire smoke. I know we just had those horrific wildfires in California, and so ASHRAE recently developed Guideline 44, and these guys are going to talk about that. If you subscribe to any podcast platform, look up ASHRAE Journal Podcast and you'll be able to find that. So my name's Drew Champlin. I'm ASHRAE Journal editor. I've got Randy Cooper, Abdel Darwich, and Mike Gallagher here with me. Real quick, if you guys just want to introduce yourself and tell everybody what you want them to know.
Randy Cooper:
Hello, I'm Randy Cooper. I work for the Association of Home Appliance Manufacturers or AHAM. I'm the vice president of technical operation and standards, and key thing that I'll be talking about today is portable air cleaners and how they can be used for a wildfire event.
Abdel Darwich:
I am Abdel Darwich. I'm a principal with Guttmann & Blaevoet in Sacramento, California. I was a member of the committee with Randy and Mike that wrote actually Guideline 44. And today mostly I will be focusing on design and sharing with you some thoughts on how to design a building so that it's ready for the next wildfire smoke hopefully.
Mike Gallagher:
And I'm Mike Gallagher. I'm president of Western Allied Corporation in Los Angeles. My focus is on the service side of the business, dealing with owners and planning with facilities folks for what to do, how to do it, how to get ready, and the things that you have to think about because you won't have time to do it when the smoke suddenly appears.
Drew Champlin:
And if you find a copy of the January ASHRAE Journal, you'll see Mike's column. It's an engineer's notebook column. It was written before the wildfires, but it's a good topical piece. Yeah. As you guys know, wildfires have ravaged and devastated portions of California. ASHRAE recently released Guideline 44, which is guidance on how to mitigate the impact of smoke on indoor air quality. So these guys are going to tell you how to do that. But Mike, you were close to the situation. Do you want to just talk about that? Any stories you want to share just about how close it was to you?
Mike Gallagher:
I've got a bunch, so you'll probably have to cut me off so that we hit time. But if you guys have seen the 550 pound black bear that hid under the guy's porch, that was one of my partners. It's been a nationwide news thing. He was in the Altadena Eaton Canyon fire and the neighborhoods on both sides of his where he lives going up the hill were burned and his strip going up the hill wasn't, so they attribute part of that to the bear. I was on two roofs in West Los Angeles within a week of the Palisades fire. There was no smoke, there was not a drop of ash on either of those roofs. That's not normal, but when you've got 80 to a hundred mile an hour and they're blowing straight down out of the hills through the towns out to the ocean, turns out they take the ash with them.
I've never seen that before with a wildfire. So it was very interesting to me to be on those roofs and see how clean they were. One of the guys that works for me is a retired fireman. He fell through a roof and he's in a second career. But restoring fire engines is his thing. He keeps one at his house, dieseled up, full of water. He and three other retired old guys went up and fought fires Tuesday night, which was the first full night, and they managed to save three houses. You saw people from all walks of life doing all kinds of stuff during that period of time. I know the news doesn't focus on that, but that was a real community effort as has been the various keeping people going and trying to figure out where we go from here efforts.
Drew Champlin:
Well, let's talk a little bit about Guideline 44 and how it can help members mitigate smoke on IAQ. One of you guys want to talk about the guideline when it was developed and how it has evolved since its inception.
Abdel Darwich:
Yeah. I mean, so the guideline, I mean, I think the idea started 2020. I mean, 2018 there was the wildfire smoke in California. It was a major impact. So the idea started then. I think the committee was formed the next year and the first actually document that the committee put together was something called the framework. They wanted something quick before the next wildfire season. So there was a kind of framework that went on. It wasn't actually a document, it was just some general guidance that went on the ASHRAE website. And then the committee continued working, eventually publishing last year.
Drew Champlin:
Yeah, it just came out. Was it December?
Abdel Darwich:
Yeah.
Drew Champlin:
So yeah, we're not even two months old.
Abdel Darwich:
Yeah. And we were lucky. I mean, we went into two publication public review with some comments. So it was a good public comment and we had a good review.
Drew Champlin:
Okay. Good timing I guess. But from a design standpoint with Guideline 44, what is the key? What do people need to know?
Abdel Darwich:
Yeah. So from a design standpoint, so the guideline actually has a chapter five, which is in the middle of the guide and it talks if you are designing a new building, what can you do to make that building ready for the next wildfire smoke? And there are two really foundational concept that the chapter tries to address. And these two were one, how can you keep the smoke out? Number two, eventually some smoke will come in, so what can you do to remove that smoke that comes in? So these are two foundational concept that chapter five try to deal with. But before, actually, I'm going to try to detail these two concept. The first thing actually, I mean, you can't deal with something if you don't know it. This is why a key aspect of chapter five is what we call the sensors so that you can know.
So this is why chapter five actually recommends adding PM2.5, which are particulate matter less than 2.5 microns, and they are the most harmful in the wildfire smoke. So we do recommend, for example, having PM2.5 Outside sensors and even PM2.5 inside the building so you can know how the smoke is migrating. We also in chapter five talk about having pressure sensors because it's very important in a wildfire smoke to keep your building positive. I mean, again, a key is to have your building always positive. Once you have the building negative, your building will act like a chimney and you vacuum all the smoke inside. We also talk about even if you don't want to have pressure sensors, you can have effluent monitoring, you can measure your outside air, your exhaust. Again, simple physics, when your outside air is more than your exhaust, your building will be positive.
So now if you go back to the first actually concept that I mentioned, which is how can you keep the smoke out? So you have to think what are the ways that smoke can come into a building? So the first one is your outside air intake. That's a major highway for the smoke to come in. So this is why chapter five talk about let's disable the economizer. When you have a wildfire smoke outside, that's not the time to save energy. So we disable the economizer. We did not recommend completely shutting down outside air because we felt that if you do that, you may have buildup of contaminant inside the building, which may become more harmful than the smoke.
Another avenue for the smoke to get and is through your building door. You have door like these doors opening and closing all the times. So we do recommend to have pressurized vestibule at the entrance if you can. If you can't, we recommend to adding air curtains that you see them sometimes in warehouses and all those spaces. And if you are lucky and, again, that's designing a new building and you're working with a cooperative architect, if you can have those doors oriented not against the wind, so downstream of the wind.
The last thing is actually that the last avenue, I guess, that the smoke can get into the building is through your envelope. Through what we call the opaque envelope. It can leak in. Although I mean, visually maybe you cannot see this, but it can get in. So this is why we encourage a lot in chapter five to talk about envelope commissioning, making sure that your envelope is commissioned. You can set a target for leakage, CFM per square foot and make sure that it's met and your building is actually very tight because that will help a lot in keeping the smoke out.
Now let's move to the next concept. I mean, you did everything you can and some smoke get into the building. So what do you do? Obviously, the first step is to filter it. And the guide actually focus a lot on filtering PM2.5 because PM2.5 is the most dangerous because it can go deep into the human lungs. So chapter five actually give two ways that you can do that. The first one is what we call the performance method, and we have actually developed a mass balance equation in that chapter. So if you know the outdoor concentration of the PM2.5, the indoor, the airflow for your filter efficiency, and your leakage, you will be able to do the math and put everything together. I can't promise that it's an easy equation, but it's an equation that you can program it in Excel. You can program it into Excel and you can play with the parameters.
Usually the way I see designer using it is they want to know what filter efficiency is needed. You can play with the indoor, with the outdoor, with the leakage, but eventually it will give you this is the filter I need. The challenges we faced is-I mean, some people ask, what's your outdoor PM2.5 in wildfire fire smoke? And we actually had some nice data provided by our counterpart in Canada about some live measurements from wildfires, and we included those in the guidelines, so you can see them. I mean, you have PM2.5 can reach 300, 400, 500, whereas in normal cases it's under the 25 or even the EPA recommend 12 and now even nine micrometer per meter cube. So we have this data. The more challenging was actually the indoor PM2.5 because today there are... And people get surprised sometimes of that, today there is no further mandate of what indoor PM2.5 level need to be.
And talking with the EPA it's like, okay, maybe it's not up to ASHRAE to regulate those. But anyway, so we finally settled on what we call the ALARA or as low as reasonably possible. So we felt if you can knock down 80% of the PM2.5, so basically get back to 20%, that should be acceptable. If you have wildfire smoke, your PM is at 300, you can bring it down to 60. That's still a huge improvement.
Now that's all the performance method. Now we understand some engineers, some owners don't like to do all this math. So we said, if you don't want to do the math, the minimum MIRV you can use is MERV 13. We found that MERV 13 is the minimum that you can stop most of the wildfire smoke. And of course, you can also go even more if you want, do gas filtration because stopping the gas will actually stop the smell. The smell is not the particulate. When you smell a smoke it's actually coming from the VOCs. Now the interesting about smoke is that VOCs are the most smellable, but are not the most dangerous. PM2.5 is the most dangerous. So this is why the guide focus on PM2.5.
Drew Champlin:
Okay.
Abdel Darwich:
Did I say enough?
Drew Champlin:
Yeah. Thanks, Abdel. If you want to take a drink of water or something like that, take a breath.
Abdel Darwich:
Yep, yep. Thanks.
Drew Champlin:
Well, we can pass that along. Randy, this may be in your wheelhouse, but from the application standpoint, do you want to address that?
Randy Cooper:
Yeah. So Abdel says you've got the building design and you've got a plan all ready to go, and then you're trying to execute this. And what I want to talk about is local air cleaning when the smoke gets into the house, making sure you're looking at that. So I'm looking at section 6.2, which is the use of portable air cleaners to filter the air in the room. And so this is both the portable air cleaners you can buy from a company or we're even going to talk about do-it-yourself air cleaners that you can build up with parts. The key is that you need to be prepared ahead of time. If the wildfire is coming and you're going to go out and try to buy either filters to replace or air cleaners themselves, they're probably going to be gone. So you do need to think about if you live in an area that has a risk of wildfires, that you've got a plan already in place and your product's ready to go.
And when you're looking at an air cleaner, there's just five different things that you want to think about. First is size. Make sure it's sized for the room that you're going to put it in, big room, small room, or is it going to be noise? So is this going to be somewhere that people are going to be talking and operating like in a school, something like that. You need to be thinking about noise. How loud is that air cleaner going to be when it's operating. Filtering, you want to focus on HEPA, which is high efficiency particulate filter, and that's getting the smallest particles. So you want to make sure that you have that or one that would be considered equivalent to HEPA. And then location, you want to be able to locate that in the middle of the room where it can get as much air as possible and be cleaning that.
And then lastly, there's some products out there that you want to stay away from in these situations, which would be ozone generators, as well as certain things that have disinfection features that may actually do more harm than good in these situations. So I'm going to go back and just talk through a couple of those quickly.
So room size, what you want to be thinking about is the clean air that's going to be coming out of the air cleaner, so how much? Cubic feet per minute is what we're talking about. And so the product will be rated for that and you're going to want to look at the smoke CADR, obviously wildfire smoke, so it's the particles that are size that you're looking at. And then what you want to do is determine the size of your room and go look for a clean air delivery rate that size. So if you've got a 10 by 12 room that's 120 square feet, go look for a unit that has a CADR of 120. That's how you would choose that unit.
Can I just talk about do-it-yourself air cleaners quickly here? So do-it-yourself air cleaners is taking a box fan and putting filters in front of it, literally with duct tape is what you're doing. So you're building it up. There's a lot of information out on the internet to talk about how to put these together either in two filters or four or five filter configurations. The more filters the better with this. And the key here is making sure you get a good seal. So if you like using duct tape, you're going to use a lot of it to get this baby tight so that it doesn't leak or anything like that.
Abdel Darwich:
I just want to mention something about portable air cleaners. We also covered this. If you are designing a new building based on actually observation that we've seen when wildfire actually happen and you want to use portable air cleaning in your facility, we found that a lot of people don't find enough power outlet to plug them. And even don't find them, and even after the wildfire is done, they don't have a place to store them. So this is why in the chapter when we are actually designing a new building, we do recommend that you have more actually power outlets so that you can plug those and you have storage area so you can put them, and again, we don't cover this, but again, our recommendation is to go and buy them in advance because if you wait until the wildfire smoke hit and you want to buy a portable air cleaner, good luck finding one.
Drew Champlin:
Yeah. We're here, if you're just joined us this an ASHRAE Journal podcast talking about indoor air quality and wildfire smoke control. These guys have done a great job so far of kind of telling you how to be prepared if you happen to live in an area like that. But Mike, back to you. You tell us a little more about the implementing, the recommendations outlined in Guideline 44, especially a smoke readiness plan.
Mike Gallagher:
Sure. Just a couple follow-on comments from the other guys. This has been a unique experience for me. I've been on a lot of ASHRAE Guidelines and Standard committees. Usually it's engineers. This one was half scientists and it was almost half Canadians because wildfire has been a big deal in Canada. I learned a good deal about the health impact things. When they've been talking about particulate and PM2.5, 2.5 micron, it's because the littler stuff isn't as big of a problem for your lungs and the bigger stuff your lungs can do a pretty good job of clearing out itself. So it's not a mystery, but that's what it is. You heard them talking about VOCs, volatile organic compounds. Some of those are good, some of those are bad. They are what you smell.
But the third thing, and this has been a big deal for our two LA fires we've had this year, is the poisonous gas. Think about all the plastic in those houses that burned, some of that stuff will knock you down. And I really hadn't considered that a whole lot, but some of these fires, it's not just the particulate and it's not just the volatile organic compounds, it's also poisonous stuff, which you hope there isn't as much of. Oh, you know what? I should also comment, you mentioned building envelopes. Nobody has a tight building envelope. If nothing else, everybody's put how many holes in to run security cameras and conduits and... It's Swiss cheese. And the reason that's important is that when you're doing your smoke readiness plan, there's about three steps.
The first one is you ask yourself, am I even going to occupy this building? If I'm not going to occupy the building, shut it all down and leave. If I'm only going to occupy part of the building. Okay. Are those on separate AC systems or separate floors or what? And then some people say no to both of those, but they're going to have areas of refuge. And the Canadian folks were talking about that because apparently they've had wildfire smoke situations that have gone on 6, 8, 10 weeks. You can't really shut everything down for that full period of time. And so you have to have basically places to retreat to, and that's where Randy and his portable air cleaners really become a factor because it may not be practical to use your overall AC system for something like that, and you may choose to handle it strictly with the in-room stuff.
Okay. So with that out of the way, smoke readiness plan, first you have this conversation about what am I going to occupy and what rooms and that. You need to decide then based on those answers, how many sets of filters do you need? Smoke itself does not clog up a filter super-fast, but ash will do it like that. And so when you're in the early stage of a fire where there's a lot of ash going, a set of filters filtering outside air is probably just a day or two or three. So then you ask yourself, how many sets of spare filters do I want to keep on hand? Bearing in mind that if that's the condition, every supply house will have already sold out by now, right? You won't be able to get any.
And filters take up space. I mean, a carton of filters is so big, a couple feet by couple feet by couple feet. They take up room. Where are you going to put them? Are you going to just rent a storage shed? I do know one facility owner who did, they went down to one of the temporary storage places and rented one of the storage lockups. How many sets of filters do you need? Well, what do you think based on your history is the duration of the smoke event going to last? The money actually for the filters themselves is kind of secondary. It's where am I going to put them? Am I going to have to rent a place to put them? Et cetera.
Now people think about carbon filters. My personal recommendation is that you not use carbon filters during the fire. You should be managing it other ways. You're going to save your carbon filters, in my mind, for when the fire is stopped. Then you use them basically for deodorizing. And they work pretty effectively. If you're not familiar with how a carbon filter works, it's a standard pleated filter that has had carbon impregnated in. It looks like somebody took a lot of really fine pepper and put it on it. That only lasts as long as the carbon can absorb the VOCs because the VOCs, the volatile organic compounds, are what? And which again, as one of the speakers mentioned, that's what you're smelling. And the VOCs as they're absorbed by the carbon leave your smelling environment, if you will. So the carbon filter's primary role in my mind, unless you have unlimited amounts of them, is to throw them in as soon as the smoke has stopped. Now there's other aspects to this planning. Let's say you've got a building engineering crew and they're going to be up on the roof, they're going to be changing filters, they're going to be monitoring stuff. Do you have masks for them? Almost all the PPE, personal protective equipment, that you're going to need is the same as what you had for COVID. If you just have the same masks that you had for COVID, you're covered. But I don't have to tell you, you probably learned during COVID that if it's not locked up, it will walk away from your site. So you need to have them, everybody needs to know how to get to them, but they need to be available when your own staff needs to use them.
What else do I have for you? Probably the key thing is building pressurization. That's the outside air piece that the other guys have talked about. The most practical thing I think, and this is what we recommend in the guideline, is for you to have two individuals, say, two service technicians, one's up on the roof, one's at the front door. The one on the roof probably goes through if, let's say, you had a building with five rooftop units, you're probably starting off by completely shutting the outside air dampers on three of them.
Now that doesn't mean that those three are pulling in no outside air because every one of those dampers leaks, you know that. But we shut, say, three of them and then you're pinching the other two and you use some judgment on which these are, and you've got that other individual standing at the front door either with a little piece of toilet paper or with their licked finger or whatever it is, and they're monitoring at what point do I lose positive pressure? Because you can feel air coming out through the crack in the doors, right? When you lose that you know no longer have positive pressure in the building. Now that does not sound highly technical. It's not because how do you calculate how many holes you have in your building envelope? How do you calculate how tight it is?
For a new building you can do that. You can make allowances, you can make assumptions, you can even test the building when the building is brand new. But when you're going into an existing building, you have absolutely no idea how tight it is. And unless you measure outside air content versus pressurization, you don't know how far to pinch it down. Now you ask, well, why am I pinching it down in the first place? It's so that those filters will actually last a day or two or three during the smoke event because that's the peak. And the final question is how do I remember where to put them? When you're done with that little exercise, you're going to want to put the dampers back to where they were supposed to be. But how do you with less than 24 hours' notice, because that's typical for these smoke events, how do you memorialize what to do and how do you get somebody to get up on your roof?
Your service contractor won't be available. You're going to have to do it with your own forces. How are you going to memorialize where to set those dampers? You going to mark them with a Sharpie and take a picture? That's not a bad approach, we're laughing, but that's not a bad approach. It's got to be something simple and it's got to be something somebody can understand and they could take the little decoupage paper and look at it and see what to do and go to the unit and do it. All of this is planning, and if you don't invest the time in the planning, it isn't going to happen. The smoke's going to come and you won't be ready. So there's a commitment to all of that required up front if you're going to have a smoke readiness plan.
Drew Champlin:
That's a lot about a smoke readiness plan as far as returning to normal operations. I guess that's just planning ahead and making sure. And is there anything else you'd want to add to that as far as it pertains to actually being able to return to normal operations after an event like this?
Mike Gallagher:
I would say the toughest thing has to do with outside air economizers. They're everywhere and most of them are not set up to have a minimum position of this sort. Although there are manufacturers who now have products to do exactly that, have a smoke readiness mode for the economizer. You could do a little research, I'm sure, and figure out who that is. But for the 85% of the buildings out there that use unitary equipment and have outside air economizers in commercial buildings, figuring out how to adjust them to one point and how to them back and marking where they have to go is probably your quickest, easiest, simplest, most reliable course. And then if you want to actually get a real air balance after the event and get it all set up, that would be great. I will tell you, most economizers don't work.
I'm a service contractor, right? Half the buildings I walk into at least have the outside air system economizers either unplugged or broken or not working or whatever. They're kind of the joke of the industry from a maintenance perspective. But you're going to have to give them some attention up front in a smoke readiness plan or you're not going to be able to put them where they need to be. And then when the time, like you brought up, Drew, comes to put them back where they should be, maybe you ought to fix the ones that weren't working because you'll find them when you're doing the smoke readiness plan.
Drew Champlin:
Well, moving along, how does the application and implementation of the building measures advised in Guideline 44, how does this differ between residential and commercial settings?
Mike Gallagher:
Well, I mean Randy's already talked about both homemade and in-room air filter products. We actually anticipate their use both commercially and residentially.
Randy Cooper:
For local cleaning, that's what you're going to do. If the smoke is taking over the building, you've just got to go at it and just pull it out. And so whether it's a school, hospital, or a home, that portable air cleaner is going to be your answer to go after that.
Mike Gallagher:
The other major difference is that code requires outside air ventilation for commercial buildings. It's the rare residential building that has outside air. I mean multi-family would, but a single-family home probably is not pulling in any outside air. And so in those cases, you probably don't have pressurization. You're probably going to get smoke into the house unless you just shut down your system. And if the weather's temperate enough outside, you can do that. That might be the best decision.
Abdel Darwich:
So one key aspect, actually, just to follow up on what Mike said is that in the residences, since we don't have outside air in, theoretically, it's not possible to make it positive. So what you could do, but you can prevent it from being negative. And a wildfire smoke what I do in my house, don't turn the hood on. If you have a hood that discharged outside, don't turn on the hood, don't turn even the bathroom fan.
Mike Gallagher:
That means leaving the bathroom light off while you're in there, right?
Abdel Darwich:
Yeah. I mean, if they are linked. I mean, yeah, it could smell a little bit, but again, because why the exhaust fan and the hood, they are all making your home negative. So it's like a vacuum. So you would vacuum all the smoke in. So make sure that your house is not negative. That's key.
Drew Champlin:
And Randy, shifting gears back a little more on local air cleaning, what are some key things to know when we're looking at local air cleaning within the building?
Randy Cooper:
Okay. Well, I think the one thing we haven't talked about is a dedicated space. So you may have a large building, you may have a home and you may have some very vulnerable people in those spaces. So somebody who is going to be greatly impacted by all that smoke. And so you would want to set up your own dedicated clean air space. So we'll say this isn't a home, you're going to want to go in and seal those windows off, make sure there's no capability from that. We talked about fans in that. So if it's near a bathroom, we don't want the fan on pulling air into that, and you're going to try to create as much of a positive air environment to keep the smoke from getting there. But when you can't do that, you again use your air cleaner. So you size it for that.
The one thing that we haven't talked about as well is having monitors. And so if you have an indoor air quality monitor, and this is where you're going to be wanting to get what we've talked about, which is the PM2.5. And so you'd be able to look at that and you'd understand, is your home gaining? Is the PM2.5 increasing? Well, that means that you need to be doing more air cleaning yourself, turn off certain things that may be pulling air in from the outside. But having that monitor and placing that monitor in that dedicated space to understand, again, as the vulnerable person having the best air quality that they can. And the big thing is are you keeping up with it or is it increasing and you're getting behind on keeping things clean. And then with that, again, all you can really do is turn things off or try to add more air cleaning capability.
Mike Gallagher:
Another thing that popped up came to my mind here, I keep running into buildings where during COVID, the outside air quantity was increased. That was recommended because the solution was dilution. And if you bring in more outside air, then you're going to dilute the numbers of aerosol contaminants. Well, a lot of those never got put back when the COVID concern passed, and that's exactly the wrong place to be if you're concerned about a wildfire, because if you were bringing in 10 or maybe 15% outside air back in the day and you bump that up to 20 or maybe even 25 during that first year or two of COVID, and if you never put it back, then not only are you using a lot more energy than you should be using, but you also are just guaranteeing you're going to have a smoke problem in the building.
So another reason in your smoke readiness plan to go through and verify what you have to do to get the minimum amount of outside air to be positive, you're going to find probably some dampers that are just far more open than they ought to be. I mean, this is not a bad thing to do just in general, but if you need the wildfire smoke concern to push you to take some action, that's probably a good thing.
Drew Champlin:
Well, Abdel, can you shed some more light on Guideline, ASHRAE Guideline 44 as it pertains to healthcare facilities, hospitals, stuff like that?
Abdel Darwich:
Yeah, sure. So hospitals, they're always unique facilities, but especially in wildfire smoke they deserve a little bit more attention because first hospitals is the first line of defense. So people, when they're affected, they go to the hospitals. Also, hospitals, it's very difficult to evacuate the hospital. It's usually the last building to be evacuated. And third, hospitals actually have the most sensitive populations. You have their people who have lung disease, and you have even newborn babies that have underdeveloped lungs. So this is why all the measure we talk about, it's very important to pay close attention to hospitals. I mean, luckily hospitals have the highest filtration that usually can find on any commercial building. So from filtration aspect, they are covered. But hospitals have a lot of pressure requirement between spaces.
So it's very important when you are playing with all your outside air, like Mike said that you don't upset the pressure inside each room, like you all need to be positive, your AII need to be negative. So it's very important to pay attention to the pressure, not in the whole building, but even from space to space. And also, we always-I mean, we are HVAC engineer, we tend to always think about HVAC with air, but in a hospital we have to think for filters, even not only for HVAC. I mean, AHUs are not the only equipment pulling air from the outside. So during the wildfire that we saw in California, I talked to some hospitals owners actually. For example, you have your compressed air, your medical air that provide air for all the instruments in the hospitals, that's sucking air from outside. And that has a filter and that filter plugged, which made the hospital not have medical air and they couldn't find a filter replacement.
Another, actually the owner had issue with the NICU incubators. This is the incubators where you put the newborn babies. So those actually NICU incubator on the bottom, they have HEPA filter. And although your system actually in the hospital is cleaning the air, but those HEPA filter, because they are HEPA, they were plugging quickly and it was actually affecting the newborn babies and they didn't have enough actually replacement filter. So for hospital, it's very important to have a full list of all the filter they have, not only for HVAC. Any equipment that had a filter, air filter, they need to know about it and they need to stock filters for it.
Drew Champlin:
Well, we do have about 10, 12 minutes. This podcast is on indoor air quality and wildfire smoke. ASHRAE Journal Podcast. This will be released in early March on all podcast platforms. Please search for ASHRAE Journal Podcast or go to ASHRAE.org and find the technical resources. Does anyone here have any questions they want to ask our guests? We do have a question. This is fantastic. Can you say your name?
Sterling Butler:
Yeah, of course. Sterling Butler, mechanical engineer with Arup. So my question was specifically related to healthcare. You're talking about shutting off some of the economizer dampers that you may have. What if you have a hundred percent outside air system?
Abdel Darwich:
That's a very good question actually. So if you have a hundred percent outside air system, you have, I mean, so you have two options. I mean, you could consider going to recirculating if you can. Some equipment can allow you this. If not, then you have to just have to change filters more frequently. That is not really a best solution if you have a hundred percent outside air units. And that's interesting. I mean...
Mike Gallagher:
I'll add to that. You generally are going to want to have a couple of extra outside layers on a DOAS or any kind of outside air unit that you're dealing with. Again, the thing that plugs the filter isn't the smoke, it's the ash. You can have some pretty inefficient filters that'll catch a fair amount of ash. I mean, we roll a filter media over the outside air intakes as a secondary layer. We've got some people that put an extra filter rack on the outside and we put a filter there and then maybe we put roll filter on the outside of that. It depends. We talked about hospitals, but police stations and fire stations are two other places that are 24/7. And you're thinking, well, the firemen are out fighting the fire. They're not in the fire station. Well, they go back to the fire station to sleep. So all of this is a plan is necessary. You were going to say something else.
Sterling Butler:
So I guess following up more specifically focusing on a hundred percent outside air, because I'm also working on laboratory facilities design where you have these a hundred percent outside air systems. And so as it specifically pertains to a smoke readiness plan, I'm wondering if there are any standardized procedures for, you offered a couple of solutions I was just going to ask about, but I'm wondering if there is a standard approach to a smoke readiness plan for a hundred percent outside air systems.
Mike Gallagher:
Abdel and I are looking at each other. I'm going to say no. I don't think there's a one size fits all, but do you have a different opinion, Abdel?
Abdel Darwich:
No, I agree with you actually. Actually, let me take-no. So the answer is that is really nothing you can do much with a hundred percent outside air. But again, it's just not about this. The world is changing. I am a building designer and so I design buildings and if somebody would come to me five years ago and will tell me, "I want you to design a building that at the same time will be able to handle a pandemic, wildfire smoke and an earthquake," I would tell them- This is really an-
Mike Gallagher:
You get that question now, Abdel.
Abdel Darwich:
Yeah, exactly. I would tell them no, that's... It's really impossible to get those three emergencies at the same time. And look, I mean, I am sitting in Sacramento in North California, September and October of 2020. So 2020, everybody knows what happened in 2020. We had the COVID.
Mike Gallagher:
Destroyed the Cabernet Sauvignon crop in Napa.
Abdel Darwich:
And then we got the wildfire smoke in California that were blowing in. This is when you saw pictures when San Francisco turned the sky orange. And obviously, we're in California, the earthquake is something we're used to, but at the same time we had earthquakes. So can you imagine we had an earthquake, so we have big equipment that are seismically rated, and then we had a pandemic and we had wildfire smoke. So people were actually calling me and say, "Should I increase? I mean, I already increased my system to a hundred percent outside air for the pandemic, but now I have wildfire smoke. What should I do? Increase it? Decrease it?" And at that time, that was pre-Guideline 44, pre-Standard 241. So people really didn't understand what to do in these things. Obviously, now we have 241 that say, okay, you don't need to have a hundred percent outside the pandemic.
They are specified rates that you can find them in Standard 241, that you can go there and find them. But again, this thing happened. I designed a building recently and we have this massive AHU, to answer your question, and it's a hundred percent outside air unit with exhaust, but we did not, and again, so what we did inside that unit actually we put a bypass damper. So that bypass damper will allow you to use the exhaust back in case of wildfire smoke. Again, you are recreating some of the toilet air, but again, you think about it, smell of the toilet or wildfire smoke? Again, that's part of your smoke guidance plan. If you're ready to take this. But again, it's an option. Not everybody can do it. Not everybody has an outside air and the exhaust and one system next to each other. But again, that's one thing from a design perspective.
Mike Gallagher:
Guideline 44 is a little unique by ASHRAE standards because there's some pretty theoretical stuff. I remember raising my eyebrows when I first looked at Abdel's mass balance equation. But then there's also very practical stuff. Another one of our committee members was the fellow named Tom Javins was the facility's director at the University of Montana. Some of the pictures in Guideline 44 are of units where he taped filters over economizer openings and wrapped various other things around. This is a kind of a situation where it can be addressed anywhere from the initial design up to, okay, I got it now, and what do I do with the thing that I inherited that it's 30 years old, right? It applies to all of those sorts of scenarios. Again, in my mind, for most existing building owners, the smoke readiness plan is the key thing. But if you're at the front end and you're actually designing a building, there's a whole chapter of good stuff in there for you.
Drew Champlin:
All right, we do have about five more minutes. Any more questions in the audience? Got another one. You open up a can of worms here when you invite a-yeah. Just introduce yourself.
Fernando:
Hi, I'm Fernando. Well, what do you guys do outside of filtration in regards to air quality and what's your opinion on a high-intensity UV?
Randy Cooper:
Well, I'm going to jump to the high-intensity UV. It's very good at killing microbes. I don't know. I don't see any in the ceiling here, but they are finding their place into use and so that's good, but you do need to make sure that you are monitoring ozone creation with that and it's got to be sized properly is what I would say.
Abdel Darwich:
Yeah. I mean, as we said, there are other options of filtrations, especially when you go to gases. For this edition of the guideline we focus more on PM2.5, but now we are actually hoping to put the standard on continuous maintenance. Actually, there is a lot of science coming out of trying to understand what the wildfire smoke is actually made of. Because before you actually can filter, you need to understand what you are filtering. And now for example, we start getting, oh, there is maybe PM1 even, not PM2.5, what type of gases? Mike talk about the ashes. So we did not exclude or include any other type of filtration, but we started with simple particle filtration with MERV, with understanding that in the future we're going to expand once we understand more the physics. I mean, because really wildfire smoke is very complex and each fire is different than the other. I mean, the composition varies, depending what's burning at what temperature, what the humidity, the wind condition, how far you are. All of this affect the composition of the wildfire.
Mike Gallagher:
Yeah. The smoke coming out of a forest wildfire is utterly different than when your subdivision burns down. And so there's a lot more to be figured out. I mean, what UV does really well is degrade carbon-based anything. That's why it kills the microbes. It's why it-but whether it would do much, the ash is too big for it to try to do anything with. Whether it would do something effective with the smoke. I honestly don't know. And I'm not sure that a lot of other people know either. So I think that's something that has to be figured out.
Drew Champlin:
Well, we probably are running out of time, probably need to wrap this up. Man, really appreciate the audience participation in this. Didn't ever think we'd get some of that, but it's been a great podcast on IAQ Wildfire Smoke Control. Please do subscribe to the ASHRAE Journal Podcast on all podcast platforms. We also have another separate ASHRAE Journal podcast called Hot Air. But yeah, I wanted to just thank Randy Cooper, Abdel Darwich, and Mike Gallagher for sharing your time and your expertise. So if you're here, give them a...
Abdel Darwich:
You're welcome. Thank you.
Drew Champlin:
Yeah. And I'm Drew Champlin. Appreciate all you guys hanging around and look forward to having this go out on the airways.
ASHRAE Journal:
The ASHRAE Journal Podcast team is editor, Drew Champlin; managing editor, Kelly Barraza; producer and assistant editor, Allison Hambrick, assistant editor, Mary Sims; 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.