Latest / The SHEA Podcast / COVID-19 the Role of Ventilation and Filtration with ASHRAE (Part One)

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COVID-19 the Role of Ventilation and Filtration with ASHRAE (Part One) · The SHEA Podcast

• 0:10
  SPEAKER_00: Welcome to We're All In This Together, COVID-19 Allies and Infection Prevention Podcast Series as part of the Society for Healthcare Epidemiology of America Shoulday Rapid Response Program.
• 0:21
  SPEAKER_00: My name is Erica Chinoy, and I'm an infectious diseases physician at Massachusetts General Hospital and Associate Chief of the Infection Control Unit at MGH.
• 0:30
  SPEAKER_00: I'll serve as your chain moderator today.
• 0:32
  SPEAKER_00: I'm happy to welcome Jonathan Flannery.
• 0:34
  SPEAKER_00: He is the Senior Associate Director of Advocacy at the American Society for Healthcare Engineering of the American Hospital Association, and he'll be here representing Ashtri, the American Society of Heating, Refrigerating, and Air Conditioning Engineers.
• 0:48
  SPEAKER_00: I'm also pleased to welcome Dr.
• 0:50
  SPEAKER_00: David Weber, an infectious diseases epidemiologist at the University of Carolina Chapel Hill, where he is professor of medicine and pediatrics, and he's here representing today.
• 0:59
  SPEAKER_00: The discussion of the podcast does not reflect Shay's or Ashtri's perspective, but facilitates communication of multiple perspectives and experiences as we go through this challenging time together.
• 1:09
  SPEAKER_00: Given the intense focus on facility design and specifically the role of ventilation and filtration in reducing the risk of transmission of pathogens, including SARC COVID 2 in healthcare facilities, we have a two-part podcast.
• 1:21
  SPEAKER_00: In part one, which is today, we'll learn about ventilation, use of pressurization, and filtration in both healthcare facilities and other locations, and the regulatory requirements that set the standards.
• 1:32
  SPEAKER_00: We will also cover some of the different ways in which engineers and hospital epidemiologists describe transmission of pathogens such as SARS COVID2.
• 1:40
  SPEAKER_00: Then in part two, we will cover some of the most commonly posed questions to both the facilities engineers and epidemiologists related to modifying ventilation, pressurization, and filtration, and learn about the role of ultraviolet genocidal irradiation or UVGI, whether plexiglasses of panacea, and some of the top research questions our guests have for the future.
• 2:01
  SPEAKER_00: So let's get started with part one.
• 2:03
  SPEAKER_00: Jonathan, healthcare facilities must be designed, operated, and maintained in accordance with many prevailing regulatory codes.
• 2:11
  SPEAKER_00: Some of those codes include the National Fire Protection Association's NFPA 101, the Life Safety Code, NFPA 99, Healthcare Facilities Code, the Facility Guidelines Institute's Guidelines for Design and Construction of Healthcare Facilities, as well as the accreditation requirements of the Joint Commission, the Occupational Safety and Health Standards or OSHA, NFP 99, which references ANSI Astray ASHT standard 170, ventilation of healthcare facilities, which governs ventilation and filtration requirements in healthcare facilities, and then ANSI Ashty Standard 62.1, which governs other occupancies, so places other than clinical locations.
• 2:50
  SPEAKER_00: So there's a lot of these regulatory codes and guidelines.
• 2:53
  SPEAKER_00: And as we get started, can you orient us on the basics of ventilation, pressurization, and filtration, and how these major standards apply?
• 3:03
  SPEAKER_02: We'll be glad to, Erica.
• 3:04
  SPEAKER_02: Ventilation is one of the key components, and I'd like to start with that first.
• 3:09
  SPEAKER_02: One of the most important components of our ventilation systems within healthcare facilities, especially, is what we call outside air or the makeup air that we introduce into the system.
• 3:21
  SPEAKER_02: Within Standard 170, there are requirements for various different types of clinical spaces in regards to the amount of outside air that is required to be put into those spaces.
• 3:34
  SPEAKER_02: One of the key concepts here is dilution is the solution, and by introducing outside air, we help to dilute the air within the room and hopefully take care of any contaminants or anything inside there.
• 3:46
  SPEAKER_02: As the outside air is brought into the system, it goes through a filtration process that we'll talk about a little later, and then is heated or cooled based on the temperature outside within what we call an air handler.
• 4:00
  SPEAKER_02: That air handler has large fans that then pushes the air down the ductwork, which is a series of metal tubes and compartments that distribute the air throughout the entire facility.
• 4:13
  SPEAKER_02: As we break this down into a single room, a patient room is a good example.
• 4:18
  SPEAKER_02: The amount of air that comes into that room, Astray ASCII standard 170 again requires what we call an air change per hour amount in those rooms.
• 4:30
  SPEAKER_02: And different types of rooms have different air changes per hour requirements.
• 4:36
  SPEAKER_02: So in a patient room, we're looking anywhere from four to six air changes per hour, depending on the type of patient room.
• 4:43
  SPEAKER_02: What that means, an air change per hour, is the amount of air that comes into the room and then leaves the room has to meet the volume of the room 12 times over the hour, or six times over the hour, or two times over the hour, depending on the number of air changes per hour required within that space.
• 5:04
  SPEAKER_02: As you mentioned previously, Erica, there's actually the second standard known as standard 62.1 that defines the requirements for other spaces within a hospital that may not be clinical.
• 5:18
  SPEAKER_02: As an example, 62.1 governs offices.
• 5:22
  SPEAKER_02: Not just offices in a hospital, but offices in a normal office building or anywhere else.
• 5:28
  SPEAKER_02: Standard 62.1 handles things a little bit differently because it looks at occupancy and square footage more than it does the air changes or the volume of air coming and going from the room.
• 5:41
  SPEAKER_02: And that's mainly because the spaces that it regulates or it oversees are really an occupancy-based type setting.
• 5:49
  SPEAKER_02: Office, your occupancy is based on requiring 15 square feet per person.
• 5:54
  SPEAKER_02: So again, it goes to a square footage requirement there.
• 5:57
  SPEAKER_02: And that's how they determine the amount of cubic feet per minute, cubic feet of air per minute that comes into the space.
• 6:05
  SPEAKER_02: Standard 62.1 does require outside air for some of this and filtration and all that stuff.
• 6:12
  SPEAKER_02: So that so that's really the basics of ventilation.
• 6:16
  SPEAKER_02: It's bringing air from outside, moving it along through a system in the proper amounts, putting it into the space, and then extracting it from the space.
• 6:25
  SPEAKER_02: So that's our ventilation.
• 6:27
  SPEAKER_02: Let's talk a little bit now about pressurization, because pressurization is a very important aspect when it comes to healthcare facilities.
• 6:34
  SPEAKER_02: We use pressurization a lot to protect and to contain things.
• 6:40
  SPEAKER_02: The most prevalent use of pressurization is what we call negative pressure.
• 6:44
  SPEAKER_02: And this is where we are, as I mentioned in our ventilation scheme, we are actually extracting out or exhausting more air than we're supplying.
• 6:54
  SPEAKER_02: So that makes the room negative.
• 6:57
  SPEAKER_02: So it's always sucking air into the room.
• 7:00
  SPEAKER_02: This becomes vital when we're looking at issues like the pandemic that we have, or even more importantly, those truly airborne infectious diseases, because we know that travels through the air, so we want to make sure that that air is being exhausted out.
• 7:15
  SPEAKER_02: We call the negative pressure rooms that we typically think of are known of as airborne infection isolation rooms or AIIR rooms, as we call them.
• 7:25
  SPEAKER_02: And this is where we'll put a patient who has a airborne infectious disease, such as tuberculosis.
• 7:32
  SPEAKER_02: One of the facilities that I worked at prior to coming to work for Ashie, I was a facility manager at multiple facilities from for 20 plus years.
• 7:40
  SPEAKER_02: And one of those facilities had a high case rate of tuberculosis because it's part of the country that I was living in at the time.
• 7:48
  SPEAKER_02: And tuberculosis is airborne and is quite impactful to people.
• 7:53
  SPEAKER_02: So we want to make sure we're handling this properly.
• 7:56
  SPEAKER_02: AIIR rooms are those rooms that you put this type of a patient in, and we exhaust that air directly out to the outside all the time.
• 8:06
  SPEAKER_02: Because we know by getting it outside, the dilution factor happens and it really reduces the opportunity to spread that contaminant, that disease.
• 8:14
  SPEAKER_02: AIIRs are required to have a minimum of 12 air changes per hour.
• 8:20
  SPEAKER_02: That's calculated by the exhaust, not by the supply, because it's a negative pressure room.
• 8:25
  SPEAKER_02: When we look at the different types of rooms, when we talk about a negative pressure room, we calculate the air changes by the exhaust, the amount of exhaust that happens.
• 8:35
  SPEAKER_02: The other type of room that we use are our protective environment rooms or the positive pressure rooms.
• 8:41
  SPEAKER_02: We use these more to protect the patient who may be immunocompromised, patients who have had any kind of a transplant, that type of a patient.
• 8:51
  SPEAKER_02: Burn patients are another patient that we protect with positive pressurization.
• 8:56
  SPEAKER_02: In this type of a room, we actually supply more air than we exhaust.
• 9:00
  SPEAKER_02: Therefore, there's more air coming into the room, and it's just like blowing into a bag that has a hole in it.
• 9:06
  SPEAKER_02: If you blow into that bag more air than is pulling out, it's going to force air out of the bag.
• 9:12
  SPEAKER_02: So that's an example of a positive pressure room.
• 9:15
  SPEAKER_02: These rooms are extremely important to be maintained properly.
• 9:18
  SPEAKER_02: They also require 12 air changes per hour, but as I mentioned previously, they're actually calculated based on the supply into the room and not the exhaust because we're supplying more and we want to make sure it stays positive.
• 9:32
  SPEAKER_02: Another key component of our efforts is filtration.
• 9:35
  SPEAKER_02: Filtration is required through both the standard 62.1 and standard 170.
• 9:42
  SPEAKER_02: Filters are rated by what we know as the minimum efficiency rating value or the MERV value, as we call it.
• 9:50
  SPEAKER_02: Within that air handling system, as I mentioned previously, you have filters in it that help to filter the contaminants or debris within the air.
• 9:59
  SPEAKER_02: As the air comes in from the outside, it'll hit what we know as the pre-filter.
• 10:03
  SPEAKER_02: And those are typically a MERV 7 or MERV 8.
• 10:06
  SPEAKER_02: Within the industry, we talk about it supposed to catch the leaves and the birds so that they're not coming through.
• 10:12
  SPEAKER_02: It's mainly to catch the larger debris and items so that those aren't getting caught up into your air handling equipment.
• 10:20
  SPEAKER_02: That's your pre-filter.
• 10:21
  SPEAKER_02: Once it goes through the what we call the coil, and a coil is really nothing more than a big radiator, just like you have in your car.
• 10:30
  SPEAKER_02: It's a lot of fin tubes.
• 10:32
  SPEAKER_02: And we run either cold water, chilled water as we call it, through that coil to chill the air, or during wintertime, we run steam or hot water through it to warm up the air.
• 10:44
  SPEAKER_02: So that's how that is done with an air handling unit.
• 10:47
  SPEAKER_02: Versus in your house, typically a unit actually has a combustible process.
• 10:52
  SPEAKER_02: You know, it burns gas, natural gas typically.
• 10:55
  SPEAKER_02: It burns natural gas right in the unit, and that's how it heats the air up.
• 10:59
  SPEAKER_02: We don't do that in a hospital because that would be too dangerous for our patients.
• 11:02
  SPEAKER_02: So again, we use those coils.
• 11:04
  SPEAKER_02: The pre-filter is really to help protect that coil, keep it from getting dirty, because if it gets real dirty, air can't get through it.
• 11:11
  SPEAKER_02: So that's why we make sure we protect that, just like your filter on your car.
• 11:15
  SPEAKER_02: Downstream of the coil, we have the filter bank, and that will be based on the type of room or type of area that the air handler is actually serving.
• 11:28
  SPEAKER_02: A great example on that are our operating rooms.
• 11:31
  SPEAKER_02: We want to make sure that nothing is getting into the operating room that could cause harm to a patient.
• 11:36
  SPEAKER_02: So there we use a high-efficiency particulate air filter, known as a HEPA filter, which is very efficient, it captures very small particles.
• 11:46
  SPEAKER_02: One of the things that is a little bit confusing with our status today is that the HEPA filter is actually built or it's tested based on 0.3 micron size particles.
• 12:00
  SPEAKER_02: What we have found in testing air filters, and this was discovered many years ago, long before I was involved with any of this, but what they found was that the 0.3 micron particle is actually the most difficult particle to capture.
• 12:14
  SPEAKER_02: Because of its size, it tends to flow in a direct flow pattern, whereas anything smaller than it gets caught up in the turbulence and bounces all over.
• 12:22
  SPEAKER_02: The 0.3 micron particle flows in a direct stream.
• 12:26
  SPEAKER_02: So making sure that you're capturing those, that size, is how we rate our HEPA filters.
• 12:33
  SPEAKER_02: So a HEPA filter actually does a much better job capturing smaller particles and larger particles than it does on the 0.3 micron particles.
• 12:42
  SPEAKER_02: So that's why we rate them based on their efficiency in capturing those.
• 12:46
  SPEAKER_02: And a HEPA filter is typically 99.7% effective in capturing a.3 micron particle.
• 12:54
  SPEAKER_02: And again, depending on the various areas of the healthcare facility, you could have different types of filters within the air handler.
• 13:01
  SPEAKER_02: All clinical areas are served by MERV 14, MERV 16, or HEPA filters.
• 13:07
  SPEAKER_02: But your office areas could be served by a MERV 8 or a MERV 12.
• 13:10
  SPEAKER_02: So that's how that's broken down.
• 13:12
  SPEAKER_02: That really depends on the amount of people.
• 13:16
  SPEAKER_02: The office areas or the non-clinical areas are based on occupancy.
• 13:20
  SPEAKER_02: One of the things that we also do, especially for construction, is we use portable filtration machines.
• 13:27
  SPEAKER_02: We call them PEPA machines.
• 13:28
  SPEAKER_02: And these are used to actually create a negative pressure within a construction area to be able to make sure that none of the work that we're doing in the construction area is getting outside of the area and impacting anybody outside of it.
• 13:41
  SPEAKER_02: Because we know when we're doing construction, we create a lot of dust.
• 13:44
  SPEAKER_02: There's a chance of stirring up different funguses and bacteria and that kind of stuff.
• 13:49
  SPEAKER_02: So we want to make sure we keep all that contained.
• 13:52
  SPEAKER_02: So we'll use a portable HEPA machine for that.
• 13:54
  SPEAKER_02: We have also seen that there's been some use of that when it's come to trying to help filter for the current pandemic.
• 14:02
  SPEAKER_02: So that covers filtration and ventilation.
• 14:05
  SPEAKER_00: One question, Jonathan.
• 14:07
  SPEAKER_00: So when you talk about the standards, when do they apply?
• 14:09
  SPEAKER_00: Because standards are always changing, they're always in evolution.
• 14:12
  SPEAKER_00: So maybe speak a little bit about how you figure out which one applies to the building that you're in.
• 14:18
  SPEAKER_02: That's a great question, Erica, because it really does depend on not only the building you're in, but when the actual section of the building you're in was actually built.
• 14:28
  SPEAKER_02: The process that we follow is that when you build something new, you have to build it to the current adopted standard.
• 14:36
  SPEAKER_02: Currently, the latest edition of Ashray Ash E170 is the 2017 edition.
• 14:43
  SPEAKER_02: We're getting very close to publishing the 2020 edition here very soon.
• 14:48
  SPEAKER_02: But right now it's a 2017 edition.
• 14:50
  SPEAKER_02: So anything being built today would be built by it.
• 14:54
  SPEAKER_02: Of course, many hospitals were built many years ago and have been expanded over the years.
• 14:59
  SPEAKER_02: So the way these requirements function is that you go to the current standard that it was built to at the time that it was built, and making sure that you understand that that is the case.
• 15:11
  SPEAKER_02: The standards do change.
• 15:12
  SPEAKER_02: Probably our best example of that are bronchoscopy rooms, endoscopy rooms.
• 15:18
  SPEAKER_02: Endoscopy rooms actually went from being negative because back in the day, you really didn't have a true endo room only.
• 15:26
  SPEAKER_02: You had an endo bronch room.
• 15:28
  SPEAKER_02: So because of bronchoscopy, you always wanted it to be negative.
• 15:32
  SPEAKER_02: Well, as endorum, as endoscopies became more and more prevalent, we started creating just endoscopy rooms.
• 15:39
  SPEAKER_02: So we realized that, well, that doesn't really need to be negative because you're actually more concerned about the patient.
• 15:46
  SPEAKER_02: So we went to a positive endoscopy room, and then we found out that, well, you know, we're not really taking and opening a patient up or anything like that when you're doing endoscopies.
• 15:56
  SPEAKER_02: So we finally settled on the fact that an endorume can be neutral.
• 16:00
  SPEAKER_02: It doesn't matter if it's negative or positive.
• 16:03
  SPEAKER_02: But if you have an endorume combined with a bronch room, then it has to be negative because bronchrooms have always been negative.
• 16:08
  SPEAKER_02: But that's a great example of how things can change.
• 16:11
  SPEAKER_02: And especially as we do more research and develop different types of rooms for the various cases that are going on, such as the pandemic right now.
• 16:20
  SPEAKER_02: There have already been and will continue to be many discussions within the Ashray Ashley 170 committee that I sit on in regards to the pandemic and what changes need to be made.
• 16:31
  SPEAKER_02: And those changes will come forth in later editions of the code.
• 16:35
  SPEAKER_02: So again, as we get later on, you'll have a different edition to go to.
• 16:39
  SPEAKER_00: So that was a great explanation with the endo and broncoscopy rooms, how things can change over time.
• 16:44
  SPEAKER_00: I guess I'll, Jonathan, I'll ask you one more question and I'll turn to David.
• 16:47
  SPEAKER_00: The question is you've talked a little bit about ORs and procedure rooms, and maybe you could give us a sense of how these ACHs and filtration applies to someone's home, just briefly, and then I'll ask David to start talking about how epidemiologists and engineers think about perhaps transmission in different ways.
• 17:06
  SPEAKER_02: So, in comparison to the way that your system works at home, at a home, you actually have complete outside air.
• 17:13
  SPEAKER_02: You're always bringing in outside air and blowing it in, and then it cycles around your house.
• 17:17
  SPEAKER_02: And our houses tend to be not very well sealed.
• 17:21
  SPEAKER_02: All right.
• 17:22
  SPEAKER_02: So they tend to leak a lot, is what we call it in the industry.
• 17:25
  SPEAKER_02: So there's a lot of leakage in a residential home.
• 17:28
  SPEAKER_02: Front door leaks, your windows leak, etc.
• 17:30
  SPEAKER_02: etc.
• 17:31
  SPEAKER_02: So that's where the air actually goes, and you're constantly bringing in new air.
• 17:35
  SPEAKER_02: In healthcare and in office buildings, we do it a little differently.
• 17:39
  SPEAKER_02: Our commercial buildings, and especially in hospitals, we tend to build them a lot tighter, as we call it.
• 17:45
  SPEAKER_02: The building envelope itself is much more sealed.
• 17:49
  SPEAKER_02: So the air can't get out that way.
• 17:51
  SPEAKER_02: So what we do is we exhaust air from our systems, but we also to conserve energy and to make sure that we're not costing significant amounts of energy, we take and recirculate air.
• 18:03
  SPEAKER_02: So that's very important.
• 18:04
  SPEAKER_02: And when it comes to an OR, those types of areas, we can't recirculate air as much.
• 18:11
  SPEAKER_02: So we'll have much more outside air coming into an OR than you will into just a normal patient.
• 18:17
  SPEAKER_02: And even more outside air into a normal patient room than you are into your office spaces.
• 18:22
  SPEAKER_02: So again, it's important to understand how that's done, and that air is recirculated back through the exhaust system to the return air system and is mixed with the outside air just on the other side of the pre-filter.
• 18:36
  SPEAKER_02: So that comes back in, and then it goes through, gets heated andor cooled, goes through the final filter, and then back into the system.
• 18:43
  SPEAKER_00: So back in the spring, Ashrie released a statement and they said that ventilation and filtration provided by heating, ventilating, and air conditioning systems can reduce airborne concentration of SARS-CoV-2 and thus the risk of transmission through the air.
• 18:56
  SPEAKER_00: And they used the term airborne.
• 18:59
  SPEAKER_00: And I think when we think about that from a hospital epidemiology perspective, when we think of airborne diseases, we think of them a little differently.
• 19:06
  SPEAKER_00: So I'll ask David to think about how hospital epidemiologists or an infection preventionist thinks about airborne transmission in the context of SARS-CoV-2, and then turn back to you, Jonathan, about the engineering perspective.
• 19:19
  SPEAKER_01: Thank you very much for that question.
• 19:21
  SPEAKER_01: I think there's a basic difference in how we think about it.
• 19:24
  SPEAKER_01: Clearly, there are a number of respiratory transmitted diseases.
• 19:28
  SPEAKER_01: They are transmitted by aerosols or airborne spread when an infectious person expels just by talking, or more when they are coughing, sneezing, playing musical instruments, and then a susceptible individual inhales those infectious droplets and may become ill.
• 19:46
  SPEAKER_01: But for decades now, the CDC guides has sort of broken that down into two groups.
• 19:51
  SPEAKER_01: There's the group they call droplet spread, which generally is within six feet of an individual, and may actually include needing direct contact with these secretions.
• 20:03
  SPEAKER_01: This includes diseases such as influenza, RSV, many other respiratory viruses, but also other diseases such as pertussis and invasive men intercoccal infections.
• 20:14
  SPEAKER_01: And those that call droplets in general will wear a mask when we're in the room, but technically the CDC would say you need to put on the mask within six feet.
• 20:24
  SPEAKER_01: That's in distinction to what the CDC and what we use in our guidelines in infection prevention of true airborne diseases.
• 20:32
  SPEAKER_01: And those are many fewer, but we spend a lot of time being concerned about them.
• 20:36
  SPEAKER_01: They include diseases such as varicella, measles, tuberculosis, and in the olden days, smallpox.
• 20:42
  SPEAKER_01: The droplet spread diseases, there is no evidence for those diseases, and I should say that includes stories COVID too, where people in adjacent rooms recycled air out in the corridors are at risk.
• 20:55
  SPEAKER_01: On the other hand, there are many examples of people with varicellid tuberculosis being in a positive pressure room, and then people in adjacent rooms all the way down to the corridor becoming sick, nurses and nursing stations who have never entered the room.
• 21:11
  SPEAKER_01: And that's why, as Jonathan talked about, we put those people in special airplane isolation rooms with direct outexhaustics and negative pressure to prevent that.
• 21:21
  SPEAKER_01: And in fact, in one case, the small house and a natural ventilated hospital on the ground floor affected not only people on that floor, but people on floors above through outside air.
• 21:34
  SPEAKER_01: So we take different precautions.
• 21:35
  SPEAKER_01: Now one can certainly agree that the SARS-CoV-2, this six feet is a somewhat artificial boundary, and given certain settings, indoors, highly infectious patients, direct plume, somebody coughing or sneezing, poor ventilation, you can in fact get transmission occasionally for SARS-CoV-2 that would go a little bit beyond or somewhat beyond.
• 22:00
  SPEAKER_01: But that's a basic distinction.
• 22:02
  SPEAKER_01: And so obviously, when we read articles talking about airborne spread of COVID, that also makes one think: do we really need to put everyone in these airborne isolation rooms?
• 22:13
  SPEAKER_01: Do we need to worry about corridors recycled air?
• 22:16
  SPEAKER_01: And the answer in general has been no.
• 22:18
  SPEAKER_01: There has not been evidence of that type of transmission.
• 22:22
  SPEAKER_00: Jonathan, how about your thought on the way an engineer kind of uses that term airborne?
• 22:28
  SPEAKER_02: I really appreciate Erica's opportunity to talk about this because prior to getting together with you and Shay here, I hadn't really thought this through because as engineers, the way we consider it is things that travel through the air are airborne.
• 22:41
  SPEAKER_02: So we're much more literal when it comes to that impact.
• 22:45
  SPEAKER_02: Great example is, as David was mentioning, with the current pandemic, we understand it's not an airborne transmission disease, but we also know that the virus does travel in the air.
• 22:57
  SPEAKER_02: So that's where we see the opportunity to use ventilation, filtration as precautions.
• 23:04
  SPEAKER_02: One of the main primary reasons that we looked at the recommendation that you mentioned earlier was the fact that in the beginning of the pandemic, we were having a significant shortage of personnel protective equipment, PPE, for healthcare workers.
• 23:19
  SPEAKER_02: And that concern significantly impacted our recommendation.
• 23:25
  SPEAKER_02: We wanted to make sure that healthcare workers, the frontline workers were being protected, and felt that by providing additional ventilation or additional filtration if possible, we could provide better protection for those healthcare workers.
• 23:41
  SPEAKER_00: So one of the questions that we get asked relates to filtration.
• 23:45
  SPEAKER_00: I know we talked about central filtration, but there's also obviously portable filtration devices.
• 23:49
  SPEAKER_00: And you can use these, and maybe you can explain a little bit about how you use these to increase your ACHs and as well as provide some negative pressurization.
• 23:58
  SPEAKER_00: Although, again, they don't add outside air.
• 24:01
  SPEAKER_00: That's not what they do as a portable device.
• 24:04
  SPEAKER_00: You can find these, they're relatively quickly to use.
• 24:11
  SPEAKER_00: Maybe you could talk about how they work to increase your air changes per hour.
• 24:16
  SPEAKER_00: And then what are the possible downsides and how people need to think about whether or not they would even need to use one of these?
• 24:22
  SPEAKER_00: I think the need probably is a discussion with your hospital Epic folks.
• 24:26
  SPEAKER_00: And then the how to do it is a collaboration with people like you, engineers, the facility engineers.
• 24:32
  SPEAKER_02: Exactly.
• 24:33
  SPEAKER_02: And we do want to emphasize, Erica, the importance of everyone collaborating and using a multidisciplinary team when it comes to making any kind of these changes.
• 24:43
  SPEAKER_02: So there's actually two ways to take a portable negative air machine and use it.
• 24:49
  SPEAKER_02: One is as a scrubber, as we call it, a scrubber, and that's where, as you mentioned, you're just scrubbing the air.
• 24:55
  SPEAKER_02: So you're putting it in the room and the air flows through it and through the filter, but the air never really leaves the room and it's not supplying any additional air to the room.
• 25:07
  SPEAKER_02: So that's known as scrubbing the air.
• 25:09
  SPEAKER_02: So that's one way of doing it.
• 25:10
  SPEAKER_02: Another way is to actually take the negative air machine and exhaust it outside directly to the outside, if possible.
• 25:19
  SPEAKER_02: And if you do that, you actually then use it to not only scrub the air going out, but it also increases the negative pressure relationship in the room.
• 25:29
  SPEAKER_02: If you don't increase the supply to it and you're already exhausting some to the return air, and then you take an exhaust more outside, you've increased the negativity of that room.
• 25:40
  SPEAKER_00: In reference to the corridor.
• 25:42
  SPEAKER_02: Correct.
• 25:42
  SPEAKER_02: Right.
• 25:43
  SPEAKER_00: So then what are the downsides?
• 25:44
  SPEAKER_00: Because this is one of our most common requests.
• 25:46
  SPEAKER_00: What do you have to watch out for?
• 25:48
  SPEAKER_02: Probably the biggest issue of them all is the noise the machine itself makes.
• 25:52
  SPEAKER_02: Some of these machines are very loud, and you wouldn't want to put that in a patient room and then expect the patient to be comfortable with that.
• 25:59
  SPEAKER_02: They do have smaller negative air machines that aren't as noisy, but you've got to be aware of where you place them so that they don't become a tripping hazard.
• 26:07
  SPEAKER_02: You know, it's got cords, it's got an exhaust duct, those kind of things.
• 26:10
  SPEAKER_02: So you want to make sure that it's placed properly so it's not gonna be a tripping hazard.
• 26:15
  SPEAKER_02: You want to make sure that the exhaust is ideally discharged outside because again, even if you're just scrubbing the air, you can impact the pressurization within the room itself and in the corridor and in other areas.
• 26:29
  SPEAKER_02: So that's really important.
• 26:30
  SPEAKER_02: But because you are moving air with this type of a device, you're gonna create turbulence.
• 26:35
  SPEAKER_02: We know turbulence moves more stuff around in the air.
• 26:39
  SPEAKER_02: That could be a concern.
• 26:41
  SPEAKER_02: And as I mentioned earlier, you really want to watch the pressure balance within your rooms, and a negative air machine could impact that.
• 26:49
  SPEAKER_02: So making sure that you're getting in touch with your facility folks, that you're including clinical folks, that you've got your infection prevention folks, your epidemiologists all involved in discussing that is very important.
• 27:03
  SPEAKER_01: I'd like to make uh two comments, if I might, uh Erica, about uh about that.
• 27:08
  SPEAKER_01: The first is the other concern about noise would be suppressing the alarms on different medical devices.
• 27:13
  SPEAKER_01: Certainly, many of our devices are hooked up to a central nursing station, which would not be impacted.
• 27:19
  SPEAKER_01: Others often just alarm within the room, and you may miss the alarm of, say, uh an IV device that's going too slow or too fast because it's not being heard over the EPA filter.
• 27:31
  SPEAKER_01: And then, Jonathan, I do have one question for you.
• 27:34
  SPEAKER_01: For us, of course, the only way to exhaust it in most of the cases, if it's a portable HEPA machine, would be literally to take the exhaust duct and make a hole in the wall and put it through the hole.
• 27:45
  SPEAKER_01: Are there any building and other issue concerns with literally just cutting a hole and putting the exhaust duct through it in terms of outside air entering, water and moisture coming in from the outside because you can't seal it properly, fire hazards or other issue by now having a hole through your uh a cement or concrete wall.
• 28:07
  SPEAKER_02: Thanks, David.
• 28:07
  SPEAKER_02: Appreciate that.
• 28:08
  SPEAKER_02: And again, ideally, if you have a window, it's ideal to actually take it out the window because it's a type of a fenestration or the finish of that is easier to seal.
• 28:18
  SPEAKER_02: I personally would not recommend putting it through the wall itself because, as you mentioned, you are going to get issues with moisture migration into the room that could lead to mold and fungus and all kinds of really nasty stuff.
• 28:33
  SPEAKER_02: So what we recommend is looking at taking out a window and blocking that section off and putting it out there.
• 28:41
  SPEAKER_02: And if you've got the proper fenestration or the proper finish on the outside of your building, that's an ideal thing to do, is actually to exhaust it straight out the window.
• 28:51
  SPEAKER_00: Do you have to worry about whether there's an intake right out there near that window?
• 28:54
  SPEAKER_00: I think you have to watch out for that piece too, right?
• 28:57
  SPEAKER_02: Absolutely, Erica.
• 28:58
  SPEAKER_02: You really do need to consider those things because you don't want the air coming back in if there's an air intake within 25 feet of it.
• 29:05
  SPEAKER_02: That's the requirement within Ashray ASCII standard 170 is 25 feet from any air intake.
• 29:12
  SPEAKER_00: Well, I learned that from a very smart infection preventionist, so I'm I'm happy to pass that one on.
• 29:17
  SPEAKER_00: So I really want to thank our speakers for joining us today, sharing their perspectives.
• 29:21
  SPEAKER_00: This is the end of part one.
• 29:22
  SPEAKER_00: So we got the basics down here and got a lot of the vocabulary down.
• 29:26
  SPEAKER_00: In part two, if you want to join us, we're going to cover all the most commonly or most of the most commonly posed questions to both facilities engineers like Jonathan and epidemiologists like David and myself related to how do you modify or should you modify ventilation, pressurization, and filtration?
• 29:43
  SPEAKER_00: We'll talk about UVGI, we'll talk about FlexiGlass, and then some of the questions that we really think our guests feel are the most important going forward.
• 29:51
  SPEAKER_00: I want to thank you from SHA and all healthcare personnel for all that you're doing to respond to COVID-19 and let you all know that the podcast can be accessed on Shay's online education center learning CE under the Rapid Response Program.
• 30:05
  SPEAKER_00: There you'll also find additional resources such as the recorded webinars, the incredibly useful SHAY COVID Town Halls, and the additional podcast series COVID-19 update, What We Know Now, which is released every Thursday.
• 30:18
  SPEAKER_00: This concludes this episode of Analyze and Infection Prevention Podcast Series, and thank you for tuning in.