Evaluating COVID-19’s Impact on HVAC Standards for Medical Buildings

Supporting an environment free of infectious diseases has always been a top priority in the construction and renovation of medical facilities and laboratories. But will the standards guiding the installation of those systems be adequate in a post-COVID-19 world?

Efforts are under way to evaluate the current technical guidance and recognized industry standards established by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and determine if it will be necessary to strengthen those codes for buildings, and health care facilities in particular.

ASHRAE created an epidemic task force to address the challenges of the current pandemic as it relates to the effects of heating, ventilation and air-conditioning (HVAC) systems on disease transmission in multiple public and private environments, including health care facilities.

In an effort to gather data and information that could shape the future of HVAC design, the task force is consulting with several ASHRAE standards and technical committees for their perspective.

Amit Bhansali, a mechanical engineer and senior associate at WSP, is a member of the interpretations subcommittee that is a part of ASHRAE Standard 170, which provides the guidance for ventilation of health care facilities and is adopted as code in several jurisdictions across the United States. Since the pandemic hit, he has participated in monthly calls where the committee has been evaluating the situation and sharing first-hand experiences on how health care clients have been reacting to the pandemic, and how engineers have been adapting to those urgent needs.

“At the moment there have been no changes to ASHRAE Standards on HVAC systems due to the pandemic, but that will soon change,” he said. “Everything is moving super-fast, and understandably so.”

Bhansali, a health care group leader for the WSP buildings team in the Dallas office, said that the June committee meeting will include the first discussions of formal revisions of the guidelines that would discuss capacity, reliability, redundancy and flexibility of the HVAC system beneficial to not only maintaining clean air for patients but also for the caregiver in healthcare facilities.

Although the members of the subcommittees are not all the voting participants in the setting of the standards, they are playing a valuable, influential role in assessing the direction these changes could be headed.

Many standards are taking on a new level of importance in a post-COVID-19 world.

“We are asking questions like, ‘What needs to be present to convert a convention center into a hospital facility?’” Bhansali said. “Now we aren’t going to try to redefine how to build a convention center. It doesn’t need to have the bells and whistles of a medical facility. But standards may be set so that it can meet the minimum requirements needed to contain an infection or at the least provide space for general capacity for inpatient services that do not require specialized considerations, thus freeing up resources at a hospital to take care of a surge.”

HVAC engineers are giving careful consideration to how their systems can help maintain required pressurizations. They are being asked to convert neutral pressure rooms to negative pressure rooms.

A negative pressure room uses lower air pressure to allow air from outside the room infiltrate, keeping potentially harmful particles from leaving the controlled space. These rooms are essential for the care of patents already infected and keeps them isolated to avoid exposure by the general population.

“Other questions engineers are asking,” Bhansali added, “include, ‘What kind of air filtration is required before recirculation or exhaust?’ ‘Should we use UVC to disinfect air?’ ‘How should we disinfect the room once a patient is discharged?’ These questions are challenging the traditional design approach.”

The answers to these questions will lead to changes in the standard practice of health care buildings always being designed with an option of air side economizers that use 100-percent outdoor air for conditioning and to be able to exhaust all air for a single pass system. It will also set guidelines for the storage of portable HEPA filter machines to provide additional protection during an outbreak, new standards for what health care facilities need in order to have sufficient ventilator capacity and system capabilities, and optimum room configurations in the event of small-scale or large-scale surges.

One provision that will likely gain traction in medical facility design is to plan for accommodating installation of portable ante-rooms – plexiglass contained areas where personal protective equipment is put on by the caregiver before entering the patient space and removed before returning to the general hospital space.

“This temporary provision that’s being used at several facility might become a standard question during the design process,” Bhansali said. “It would not be necessary to have permanent ante-rooms installed at rooms not normally used for these purposes, as that would take up a considerable amount of floor space. But designing with the potential need to safely and quickly convert rooms for the care and treatment of patients during a health crisis is going to be a practical design consideration.”

ASHRAE has a long-standing collaborative relationship with the American Society for Health Care Engineering (ASHE), which focuses on the overall engineering needs of medical facilities to create uniform guidelines. Since the COVID-19 outbreak, Bhansali said ASHRAE and ASHE have been sharing information they have gathered to help with the process.

“Under normal circumstances the process can be time consuming, but there is an awareness that working together to expedite certain things during this process is essential,” he said.

ASHRAE follows a 3-4 year cycle for updating its standards, and the next 170 standard is likely to be released in the fourth quarter of this year and thus does not provide enough time to properly vet and address questions raised by this pandemic to be included in this update. But over the next few months, interim directives may be incorporated to guide health care facilities to make responsible decisions using information and priorities that are now at the forefront of the health care industry.

Another outcome of the pandemic is a newfound awareness of the value and necessity of many of the systems that engineers are responsible for designing and recommending for all buildings, especially in the health care industry.

“When we are collaborating with our clients, it’s incumbent upon us to educate them about these systems, what they can do, and what they will need for their particular facility,” Bhansali said. “While the standards are usually a minimum requirement, going beyond for the resiliency of the system is considered on a case-by-case basis. Facilities in urban, suburban and rural areas will each have different considerations, and will look to their engineers to custom fit the right systems for their particular needs.”

In the long term, the ASHRAE guidelines will be a valuable tool to help medical facilities make smart investments that will create safer environments, and new efficiencies to convert facility usage in the event of a future health crisis.

“We can never predict what or when something is going to happen, but we can prepare for that time when something does happen,” Bhansali said. “We need to be prepared on all fronts for viral outbreaks, whether they are airborne, waterborne or transmitted through a droplet. Engineers can provide valuable insight from experience on what will be practical and useful in the design of health care facilities.”

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