As the status of COVID-19 in the U.S. is changing daily, ESa (Earl Swensson Associates; Nashville) has been communicating with our healthcare clients and sharing proactive steps that some have already taken. While we are not offering a prescriptive solution for hospitals in general, we are sharing knowledge of what some providers are considering.

Testing negative is positive news for patients presenting symptoms. However, the testing period with reliable results is not fast enough to clear these patients when they present at a hospital. Hospitals are having to quickly react to establish containment and testing protocols.

Involving engineers
As containment examples, several hospital clients have implemented measures to adapt bed units in different ways, the differences being in HVAC system modifications:

  • Adapting an existing bed or patient treatment wing to private rooms with negative air pressure
  • Adapting existing private rooms with individual ductless units, which do not circulate through ductwork into a central HVAC system.

Commonalities of these hospital examples include:

  • Each hospital engaged a licensed mechanical engineer with a prior design history of the facility.
  • Each determined admission points that bypass the general public and have the most direct access to the selected beds or zone.
  • Each selected a zone apart from other patient populations.
  • The selected floor had capabilities to be separated from the general HVAC system of other floors or zones.

Implementing options
“Our approach in assisting our client hospitals in addressing the impact on their facility is to create a short-term negative pressure area for the treatment of COVID-19 patients that protects staff and other patient populations as much as possible,” says Mike Bishop, PE, a principal of Enfinity Engineering LLC (Brentwood, Tenn.)

“To accomplish this, we have been looking for existing patient areas of a hospital where access to the COVID-19 patient treatment area can be controlled such that interaction between the COVID-19 patients and the remaining areas and patient/staff populations is minimized,” he says.

Additionally, Enfinity is looking for spaces that can be fully converted to outside air/exhaust, with supply and exhaust airflows set so rooms are in a “slightly negative pressure condition to the adjacent corridor. “The goal in this approach is to isolate, as much as possible, the COVID-19 patients, while providing a suitable patient care area for these patients,” he says.

Another engineer outlines needs he’s encountered, as well. According to Tom Malloy, PE, a principal with Phoenix Design Group Inc. (Nashville), “As medical facilities plan for the impact of COVID-19, one of the projected needs is more airborne infection isolation (AII) patient rooms. In evaluating options for this, it is important to understand that the purpose of these AII rooms is to protect staff and other patients from the infection(s) that may be transmitted from the patient being isolated.

“These rooms do nothing to aid the patient nor do they protect the staff who are in the room with the patient. The rooms do allow staff to work outside the room without personal protective equipment (PPE) and rely on proper PPE to protect staff inside the room,” he says.

Malloy references ASHRAE standards published for these rooms that include 12 air changes per hour, with the exhaust inlet above the patient’s head. The rooms must be negative to the adjacent corridors to a minimum negative pressure that a licensed engineer should help establish according to ASHRAE standards. “Additionally, recirculating supply air in the rooms is prohibited unless the recirculated air is HEPA filtered. A local visual indicator of the pressure is required. The ASHRAE Standard 170 has been incorporated into the FGI Guidelines for Design and Construction of Hospitals and into many state regulations,” says Malloy.

He adds that substituting HEPA secondary filter sections into the air handling unit(s) supply sections is another precaution that may be elected. “HEPA filter sections require special housing assemblies and gasketing that less rigid filter efficiencies require, thus necessitating retrofit to the unit(s) assembly. Fan systems should also be evaluated as to the additional filter resistance (horsepower) the HEPA filtration would require,” he says.

Consulting authorities
It’s important that facilities and design teams understand that the modifications discussed can result in airflows to the modified patient rooms that are not code compliant as traditional isolation rooms, notes Bishop. “Authorities having jurisdiction, such as state health departments, should be consulted for approval before implementing these changes. Hospital facility directors should review and discuss these options with their consulting engineers and medical and infection control staff to help determine the right solution for their hospital,” he adds.

These facilities are finding innovative and proactive ways to house patients in contained areas, as time is of the essence. Important items to remember in this process include:

  • It is essential to involve the AHJs in any emergency measures.
  • No quick retrofit solution is fail-safe for staff and other occupants.
  • PPE and testing precautions have to be part of the strategy.
  • Since patient outcomes and management of airborne and contact infections cannot be guaranteed, signed liability waivers in design and healthcare agreements should be part of the equation.

Sam Burnette, AIA, is a principal of ESa (Earl Swensson Associates). He can be reached at