Henderson Engineers Shares Guidance for Negative Isolation Rooms, Responding to COVID-19

As a society, we are all watching the coronavirus updates, intently looking for information. We have seen information provided by the World Health Organization, Centers for Disease Control and the American Society for Health Care Engineering. As designers in the healthcare setting, we are constantly reminded of the criticality of certain spaces in regard to patient treatment and healing. Below you’ll find guidance from code (ASHRAE 170 unless otherwise noted) and outside sources for airborne infection negative isolation rooms, as many healthcare facilities are responding to the needs of this situation.

  • Negative isolation rooms must be exhausted (completely separate from general exhaust) directly to the exterior. We would recommend a HEPA filter be provided on the exhaust system to protect other outside air intakes in the vicinity.
  • If it’s impractical to exhaust directly to the exterior, it is acceptable to recirculate the return air from the negative isolation room into the air handling system only if a HEPA (MERV 17) filter is present on the return duct. Some design considerations when pursuing this option:
  • The HEPA filter needs a lot of space for installation and maintenance (if bag in/bag out).
  • A booster fan may be required to address the pressure drop from the installation of the HEPA filter.
  • The supply in the negative isolation room will require adjustment through testing and balancing.
  • Airflow rates (12 ACH) required for the isolation room will likely be higher than the current airflow for a standard patient room.
  • Provide a pressure measurement device to document space pressure.
  • Another option allowed by the CDC for similar airborne pathogens includes creating a temporary isolation tent in an existing patient room that allows for isolation of a patient with limited construction work involved.
  • Space within the isolation tent would be provided with a temporary unit to create a negative pressure environment with HEPA filter recirculation.

As published guidance can change, we would recommend reviewing the guidance provided by the organizations previously listed, as well as the links below as new information on the virus is confirmed.

CDC Guidelines for Infection Prevention and Control Recommendations for Coronavirus (continue to check this link as it is updated frequently with emerging information): https://www.cdc.gov/coronavirus/2019-ncov/infection-control/control-recommendations.html

CDC Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Settings: https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5417a1.htm?s_cid=rr5417a1_e 

ASHE Guidance for Facilities for Coronavirus: https://www.ashe.org/COVID19resources

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Posted March 23, 2020

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