Blog Post April 8, 2020 COVID-19: Considerations and Recommendations for Hospital Facility Readiness Authors Joe Moroni This is a guide intended for hospital leaders to prioritize the work activities of their facilities staff in response to COVID-19. With recent CDC guidelines stating that “airborne transmission from person-to-person (of coronavirus) over long distances is unlikely,” developing expensive or complex pressure-gradient solutions to combat coronavirus transmission should be considered a lower priority than utilizing facilities personnel to implement control measures that have been shown to effectively limit transmission and will have a greater overall impact.The high-impact and enhanced readiness actions herein should be prioritized for completion prior to beginning work on adjusting the heating, ventilation, and air conditioning (HVAC) environment within the facility.High-Impact ActionsRedirect facilities personnel to take the following actions as soon as possible:Effectively control traffic through access points to the hospital.Ensure supplies for respiratory hygiene, cough etiquette, and hand hygiene are readily available and restocked. This includes providing facial tissues and hand sanitizer as well as no-touch waste receptacles at facility entrances, waiting rooms, and patient check-ins.Consider adding waiting areas outside the hospital or allowing patients to wait in their cars and be called on their cell phone when staff are ready to transport or receive them.Establish triage stations outside the facility to screen patients before they enter.Adjust door sweeps on rooms designated for COVID-19 patients to improve airtight integrity.Install physical barriers (e.g., glass or plastic windows) at reception areas to limit exposure.Erect temporary physical barriers or partitions to direct patient flows.Enhanced Readiness ActionsAs hospitals cancel elective procedures and reduce census, units will be designated to house COVID-19 patients. The activities listed below will better enable these units to provide care and reduce infection risk. Begin work on these items once the high-impact actions are complete to prepare individual nursing units, patient rooms, or nonclinical areas to provide care for COVID-19 patients or other immunocompromised individuals.Ensure room air integrity by repairing/replacing seals or gaskets, as necessary, and adjusting or installing door sweeps.This action supports the recommendation to place COVID-19 patients in rooms with the door shut. (See CDC COVID-19 guidelines.)Remove or cover any unnecessary or excessively porous materials from rooms that will house COVID-19 patients. If visitors will not be allowed at a given facility or in certain areas, remove visitor furniture.Identify any available equipment to filter or disinfect the room’s air environment (e.g., portable HEPA filters, UV sterilizer units). Develop a procedure in coordination with EVS and Infection Prevention and Control to determine room cleaning, disinfection, and turnover protocols. For more information, refer to ASHRAE Position Document on Airborne Infectious Diseases, p. 10.HVAC Environment ActionsAs of March 26, 2020, the CDC states that airborne transmission of coronavirus over long distances is unlikely. Therefore, the recommendations listed below are in order of priority based on the ease of implementation and the relative impact that such actions would have.Temperature Control: Temporarily override night setback and/or unoccupied room temperature settings to match occupied set points.New evidence suggests that warmer temperatures might limit coronavirus transmission. Although there is no definitive evidence or recommendation for the operation of healthcare facilities in industry literature, maintaining normal, occupied temperature bands within rooms is in line with these early findings. Therefore, eliminate night setback or unoccupied set points to keep room temperatures in the normal occupied band instead of allowing them to drift to low temperatures when rooms are unoccupied. Heating rooms above normal temperature bands is not advised, since these temperatures could adversely affect patient health. (See 2019 ASHRAE Handbook, Chapter 9.)Humidity Control: Maintain normal humidity control set points and operation.The factors affecting disease transmission, mold growth, the efficacy of cleaning agents, and the impact to the respiratory system are multifaceted, and there is no clear recommendation regarding humidity targets for the control of coronavirus. (See ASHRAE Position Document on Airborne Infectious Diseases.) Maintaining these systems as you normally would is likely the best course of action.System Filtration: Replace HVAC unit air filters, prioritizing central units serving affected patients.Replacing air filters will help ensure a controlled indoor air environment, and doing so before operators are performing other emergency duties and unable to keep up with preventive maintenance will better protect the facility and equipment against failure in the future. Prioritize replacement of return air filters, but ensure all filters have been recently replaced. Add HEPA filtration or increase minimum efficiency reporting value (MERV) filter classification for units serving immunocompromised patients and/or those with highly infectious diseases. (See 2019 ASHRAE Handbook, Chapter 9.)In-Room Filtration: See Enhanced Readiness Action item 3, above.Room Pressurization Measurement: Establish an updated understanding of relative room pressure relationships.Although establishing isolation rooms is not recommended by the CDC at this time, understanding the air pressure environment within a hospital will better position facilities operators and clinical staff to make informed decisions when placing patients into rooms or staffing units. In order to quickly document the pressure relationships within a nursing unit or other area within a hospital, record differential pressure readings under each door within a unit during normal operations with all doors shut. This will help establish a baseline understanding of that unit (the CDC recommends that doors be shut when housing COVID-19 patients) and can be easily documented on a floor plan and communicated to clinical and facilities staff. Positive Pressurization of Spaces Adjacent to Patient Rooms: CDC guidelines specifically stipulate that airborne infection isolation rooms should be reserved for patients undergoing aerosol-generating procedures and do not specify that COVID-19 patients should be placed into negatively pressurized spaces. For facilities without the ability to easily convert rooms to negative pressure, however, patients and staff might feel that risk is not being properly controlled. To address this concern, hospitals can take measures to ensure that patient rooms are negatively pressurized relative to adjacent spaces without adjusting the systems within the individual patient rooms. By increasing the supply air and limiting or eliminating the return/exhaust air serving these adjacent spaces, hospitals can establish the desired pressure relationships without drawing negative pressure on any spaces, which could cause unintended consequences. (See the Negative Room Pressurization section below.)Caution: In any room pressurization strategy, add dedicated filters on the return and/or exhaust systems for rooms planned to house COVID-19 patients. Although no filters are effective in removing 100% of the virus, this added filtration will protect personnel and equipment against the possibility that the virus enters the centralized HVAC system.Portable Anterooms: Portable anterooms adjacent to rooms with COVID-19 or other immunocompromised patients will create a space to safely enter and exit without modifying the main HVAC systems controlling those rooms. Details for building and installing portable anterooms have been developed by the Minnesota Department of Health and can be found here.Negative Room Pressurization: Establishing negative room pressurization for COVID-19 patients is an additional step that some facilities can take.Caution: In any room pressurization strategy, add dedicated filters on the return and/or exhaust systems for rooms planned to house COVID-19 patients. Although no filters are effective in removing 100% of the virus, this added filtration will protect personnel and equipment against the possibility that the virus enters the centralized HVAC system.In some facilities, HVAC systems were designed with controls that allow for the establishment of negative pressure in individual patient rooms or entire nursing units. If your facility has these capabilities, implement these controls and measure pressure gradients to ensure proper operation of the system. In many other facilities, individual unit or room pressure control is not part of normal system design or operation. In these instances, a variety of factors must be taken into account and a well-established procedure documented prior to adjusting relative room pressures using the in-place HVAC system. Some of the potential unintended consequences of establishing a negative pressure space without consideration of full system dynamics include:Infiltration of outside air through windows. Because outside air has not been filtered in the HVAC system, this might introduce unintended risk for COVID-19 patients.Infiltration of air from interstitial spaces into patient rooms. If rooms are generally positive (or neutral) in pressure and turned negative, introducing air from mechanical shafts, voids, and areas above ceiling tiles might present additional health hazards for COVID-19 patients.Reduction in room air change rate. Reducing the number of air changes within a room will extend the time that coronavirus and other contaminants are present, which might increase risk to staff or extend the time required before rooms can be safely cleaned for room turnover.Cross-contamination through return air systems. Some HVAC systems—especially in older hospitals —have return air systems that draw air from a space (e.g., a patient room), back to the main air distribution equipment, and back into the spaces served by that main unit. Although this return air is almost always filtered, no filter removes 100% of contaminants, and introducing additional return air from spaces that have been turned into negative pressure rooms might present additional risk.Diminished ability to control room temperature or humidity. Adjusting a system to operate outside of its design parameters will impact the ability to control the indoor environment, which might negatively affect patient care or the comfort of patients and staff.Establishing a Negative Pressure Room Environment: With the potential risks in mind, start by utilizing central HVAC controls to increase return/exhaust air relative to supply air in patient rooms to establish a negative air environment. Increase patient restroom exhaust to establish a relative pressure gradient to make the patient room itself negative relative to the adjacent nursing station or hallway. By not reducing supply air, you will ensure that the minimum level of required outdoor air changes are maintained in the room.If increasing return/exhaust air in a system is not feasible, add temporary negative pressure isolation in targeted patient rooms by using portable HEPA filtration units with integrated fans and building temporary ductwork to direct airflow outside or into the return/exhaust air system. Detailed procedures for this approach have been developed by the Minnesota Department of Health and can be found here. Once other approaches have been exhausted, consider reducing supply air to rooms in order to establish the desired pressure gradient. Review these adjustments in light of potentially reducing outside airflow below recommendations for room occupancy, comfort, or infection control. With limited visitors and recommendations to keep doors shut during the COVID-19 response, the airflow dynamics and occupancy of hospitals are different from design conditions, meaning that reduced airflows might be appropriate in some instances. In any event, have a licensed professional engineer review these adjustments to advise you on the appropriate course of action.