Thinking about Ventilation for Long Term Care July 30, 2020

Thinking about Ventilation for Long Term Care July 30, 2020 Mary Catlin BSN, MPH, CIC, DOH, Office of Communicable Disease Epidemiology Source: Andrew Lichtenstein

Outside of hospitals we have had large COVID outbreaks In prisons Nursing homes Farm workers residential communities Dormitories and barracks Cruise ships One thing these may have in common is low rates of air exchange, air that recirculates and is shared by large numbers of people.

We know rates of respiratory infections are lower when: -Military recruits in barracks “are less crowded” (72 sq. ft./trainee). -Dorms increase Air Changes per Hour (ACH) -Taiwanese dorms increase ACH

Military respiratory infections Five studies saw lower rates of respiratory infections when military recruits in barracks “are less crowded” (72 sq. ft./trainee). Sanchez, JL et al. Respiratory Infections in the U.S. Military: Recent Experience and Control. Clinical Microbiology Reviews Jun 2015, 28 (3) 743-800; DOI: 10.1128/CMR.00039-14 Also military saw no change with head to toe sleeping arrangements, increasing distance between cots, or hanging cloth between cots. No change in ARI rate when 60 person barracks changed air flow, but didn’t increase ACH with outside air. Lower ARI rates in 8 person barracks. White DW, Feigley CE, McKeown RE, Hout JJ, Hebert JR. Association between barracks type and acute respiratory infection in a gender integrated Army basic combat training population. Mil Med. 2011;176(8):909914. doi:10.7205/milmed-d-10-00418

Maryland dorm rooms with more air changes per hour had 75% fewer lab confirmed infections: Low vent (2.3 L/s outside air) 2.83 infections per person per year High vent 6.6 L/s outside air 0.7 infections per person per year Opening Windows ventilation 2.3- 7.5 L/s Doors: 3.6 L/s Windows and doors: 8.8 L/s Zhu S et al. Ventilation and laboratory confirmed acute respiratory infection rates in college resident halls in College Park, Maryland. Environment International. Vol 37.April 2020. https://www.sciencedirect.com/science/article/pii/S0160412019341108

Room across from infectious patient developed infection: air flow Source: "Ventilation and laboratory confirmed acute respiratory infection (ARI) rates in college residence halls in College Park, Maryland": https://www.sciencedirect.com/science/article/pii/S0160412019341108

Chinese University, 2712 students in 13 buildings Self reported URI 6 times greater in students with lower ventilation rates (1 L/s/person) compared to higher (5 L/s person) Tiny rooms averaged 5 meters per person or 180 f3: (8 X 8 X 3 ft.). Is crowding different from poor ventilation? Sun Y, Wang Z, Zhang Y, Sundell J. In China, students in crowded dormitories with a low ventilation rate have more common colds: evidence for airborne transmission. PLoS One. 2011;6(11):e27140. doi:10.1371/journal.pone.0027140

Shared Air Space, Korean Call Center: 43.5% attack rate Park S, Kim Y, Yi S, Lee S, Na B, Kim C, et al. Coronavirus Disease Outbreak in Call Center, South Korea. Emerg Infect Dis. 2020;26(8):1666-1670. https://dx.doi.org/10.3201/eid2608.201274

Princess Cruise Ship Preprint: (needs peer review) from Kings College: Persons who roomed with an symptomatic case did not have higher attack rates than other persons who had recirculated air. Concluded risk of disease from shared air space, low ACH and recirculating air. Reference: https://www.medrxiv.org/content/10.1101/2020.07.08.20148775v1

Ventilation and crowding are flip sides of the same coin Crowding measured by number of persons per sq foot, and repeated CO2 concentrations ( 1000 ppm). Ventilation is volume of outside air per time. Measure Air Changes/ Hour, filtration, direction, rate exhausted to outside.

We know that respiratory infections can occur without touching 6 feet Bus Restaurant Wards Apartments SARS Amoy Garden toilet U traps dry – every time a toilet flushed droplets went into sewage vent pipe and up 8 floors. 1 case spread to 321 cases. https://www.info.gov.hk/info/sars/pdf/amoy e.pdf

Transmission on bus to others

Guangzhou, China. AC flow implicated in airborne spread. Source, CDC and Guangzhou CDC. Bay Area News Group

Letter from 239 scientists documenting airborne transmission Provide sufficient and effective ventilation Avoid overcrowding Minimize recirculated air at least in hospitals, schools and workplaces Use germicidal UV lights in air filtration systems Lidia Morawska, Donald K Milton, It is Time to Address Airborne Transmission of COVID-19, Clinical Infectious Diseases, , ciaa939, https://doi.org/10.1093/cid/ciaa939

Lawrence Berkeley National Laboratory for Indoor Air Quality (EPA) 2007 “There is strong and sufficient evidence” to demonstrate that lower ventilation rates and indoor airflow from infected to uninfected people are associated with increased transmission of infectious diseases.” Review supports AIIR in hospitals but “data insufficient to specify minimum ventilation rates” for other types of buildings. Li, Y., et al., Role of ventilation in airborne transmission of infectious agents in the built environment - a multidisciplinary systematic review. Indoor Air, 2007. 17(1): p. 2-18.

Industry standards set for energy efficiency not respiratory health HVAC industry focuses on reducing energy costs, “comfort”, control of moisture and mold. ASHRAE ventilation rates are too low to prevent respiratory infections. Older buildings are exempted. Image source: https://www.greenbuildingadvisor.com/article/p lugging-air-leaks-would-save-billions

So the question is Droplet transmission of COVID is primary, but airborne transmission exists, Can we reduce a portion of respiratory transmission in congregate settings by improving ventilation? Are there a few easy fixes or things to avoid?

Beginners Guide To HVAC watching Source: Creative Commons, WikiHow

What to look for Where does outside air come in? Where does air go out? What is the crude direction of air flow? Is air recirculating from one area to another? Do windows open? Have they made any changes to the system? Fans or filters or new exhaust path?

If COVID-19 enters congregate settings with low ACH Source: Andrew Lichtenstein

Grills

Registers are grills with adjustable dampers Source: home depot

Air Diffuser (Air in) Diffusers change the incoming direction of air flow. They can reduce the noise of the system, and give more even air supply around the room. Often in the ceiling. Source: Accord

Not Mutually Exclusive

Filters Source:https:// www.wikihow.com/Change-aHome-Air-Filter

Focus on energy efficiency lowered ACH leakage in new homes and businesses (can’t exceed 7 ACH) Older wood frame homes had 5-12 ACH from leaks Insulated concrete homes with concrete roof may be as low as .15 ACH Commercial building standard is .35 ACH/hr Tight buildings need mechanical ventilation (HVAC) Wood houses don’t always have central HVAC door blower https-//www.energy.gov/energysaver/blower-door-tests

HVAC systems: Gas furnace move air through ducts Source: Service Champtions

Boiler and radiators: Don’t supply or exhaust air. Move heated H20. Source: Hudsonread.com

Mini-split for heat and air: Don’t provide or exhaust Air

Air flow in a wood building Source: John Strab

Where to look for in coming air vent In homes, source registers (air in) are often near the floor, so hot air will rise. At least 6 inches from corner If in the wall, heating is generally across from window. Heating and cooling can have separate registers or use the same one.

Location of external residential intakes Not on roof 10 feet away, and not directly above from exhaust fan, plumbing drain, appliance vent Away from idling cars, rodent, pests and rain Don’t put generators or barbeque grills near intakes.

Cluster of deaths from carbon monoxide poisoning After a windstorm in King County in 2006, 250 cases of poisoning when HVAC on generator s brought in CO from outside, or exhaust failed t o purge houses of CO from charcoal stoves. https://www.ncbi.nlm.nih.gov/pmc/articles/P MC2724456/

Don’t cover exhaust vents, without making a new way for air to leave If you have air that recirculates from room to room, place COVID patients in rooms that vent to the outside Or use hepa filter and fan to vent to outside. Don’t exhaust into enclosed courtyards Avoid facing into prevailing winds.

Be aware of ventilation flow: in, out, flow Actual room air flow is highly turbulent, nonlinear, modeled by computational fluid dynamics Reality is pockets of dead air, and lack of air mixing. Heat sources, furniture, windows changes flow.

Ideal for COVID: Air moves clean to dirty Source: Memarzadeh 2012

Position of supply and exhaust changes air flow Source: Memarzadeh 2012

What about HEPA fans? As an neg. air flow room? Select room with door Set up window adapter Set up HEPA machine Seal return air grill Turn on HEPA filter and adjust flow

What about fans? Fan New Air Yes Window, box, tower fans in front of window. Fans can to blow air out and/or blow air in. If single fan, use in same direction air normally flowing. Don’t blow from infected person to others Don’t block window needed for fire escape

What about “air purifiers”? EPA technical guide https://www.epa.gov/sites/production/files/2018-07/documents/residential air cleaners - a technical summary 3rd edition.pdf Filters: yes, but start with routine replacement of furnace filters. Size HEPA filter units to room. Close door. UVGI: yes, upper vents and upper ceiling in crowded rooms with flow ACH. More info: http://www.stoptb.org/wg/ett/assets/documents/MaintenanceManual.pdf Generally, say “no” to the exotic untested Ozone generators: none are approved by feds for use in occupied spaces Plasma air cleaners: use high voltage and high current. May form harmful byproducts. Photocatalytic oxidation (PCO) Cleaners. “ “ Electrostatic precipitator: some have high ozone and nitrogen oxide generation, high electric power. Ionizers and ion generators: generate ozone and low effectiveness

In, Out, Flow: What can make things worse? Dampers, windows closed to avoid “drafts” Patients placed within air flow path of COVID Exhaust vents covered or blocked Fans moving air from patient (dirty) to clean, recirculating in multiple rooms. Locating crowds in areas with least ACH

Humidity?

Evaporative coolers https://www.energy.gov/energysaver/homecooling-systems/evaporative-coolers

What CDC recommends for businesses is also appropriate for LTC https://www.cdc.gov/coronavirus/2019-ncov/community/officebuildings.html Open windows and doors and use fans. Disable demand control ventilation that reduce air supply based on temperature or occupancy. Increase air filtration of recirculated air, if air handling system can manage Move air clean to dirty, move workers to clean zones. Use exhaust fans in restrooms and operate at full capacity Maintain HVAC systems, including filter changes. Consider use of UV GI irradiation in upper room air. https: www.ashrae.org/technical-resource/commercial offers pandemic advice as well Identify crowded areas and remove furniture.

Take home advice: On LTC assessments, do look for air supply, flow, exhaust: IN OUT FLOW Starting points to discuss with their HVAC expert Be aware HVAC staff are be trained to save energy costs and decrease drafts When all else is complicated, eliminate crowding and use outside air whenever possible.

Converting L/s to cubic F/hour ACH formula uses CFH/room volume Find calculator at https://www.convertunits.com/from/litre/second/to/cubic foot/hour