As a society, we are all currently watching the coronavirus (COVID-19) updates, intently looking for information. We have seen information provided by the World Health Organization (WHO), the Centers for Disease Control (CDC) and in healthcare, and the American Society of Healthcare Engineers (ASHE). 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.

  1. 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.
  1. 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.
  1. Provide a pressure measurement device to document space pressure.
  2. 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 listed above 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):

CDC Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Settings:

ASHE Guidance for Facilities for Coronavirus:

About the Authors

Mark Chrisman

Healthcare Practice Director | Principal
Mark Chrisman is a rare breed of smart. Not only does he love to learn, but he also naturally teaches those around him. Mark joined Henderson Engineers in 2004 and quickly began establishing client relationships that he still maintains today. A vice president and our healthcare practice director, Mark coordinates strategy for Henderson’s healthcare practice across the country. He has designed healthcare environments for some of the biggest names in the industry, providing technical expertise on fire protection and code consulting. He is known for his uncanny ability to recall specific codes and uses his immense knowledge of regulatory compliance requirements to help save clients’ money and time on projects. Mark often works in tandem with our team of healthcare specialists at Henderson Building Solutions. Don’t let his smarts fool you; this Ph.D. is creatively talented too. His party trick is spouting off the most recent code updates while busting out killer dance moves at the same time.

Jake Katzenberger

Healthcare Technical Leader
As a healthcare technical leader, Jake not only understands how building systems work, but how they integrate with the function of the space. He has personally performed site investigations and managed solutions for more than 75 pharmacies since 2017. Jake leverages 15 years of experience to advance the technical standards of our healthcare practice. Jake combines new technology, design innovation, and lessons-learned to push our healthcare design standards to the next level. He provides direct design oversight, resources, and mentoring to ensure a coordinated, code compliant, and functional design.