ASHRAE Journal - September 2020 - 10

LETTERS

The Author Responds
One of the facilities we worked
with requested the recirculation of
HEPA-filtered air from the COVID-19
negative pressure rooms back to the
hospital. We contacted state officials
and the hospital's infection control
officer to obtain approval. Both parties did not recommend it.
The guidance from CDC, ASHRAE
and WHO generally support each
other; however, the details regarding COVID-19 remain in flux. How it
spreads and proper methods of mitigation are still being explored by scientists and engineers alike. Therefore,
as mentioned in the article, it is critical to perform any work in conjunction with the authorities having jurisdiction and to obtain prior approval.
We understand that within a climate such as Southern California,
high humidity is not generally a
problem. In this scenario, we closely
followed the California OSHPD
PIN-4 and coordinated with infection control staff to implement the
steps as included in the case study.
We also carefully reviewed the available capacities within the systems,
including makeup air and the effect
on adjacent areas. We suggest you do
the same and follow the guidelines
established by authorities having
jurisdiction in the state of Florida.
Frank Shadpour, P.E., Fellow ASHRAE, and Stefanie
Johnson, San Diego

Guidance for
COVID-19 Building
Operations
The May 2020 ASHRAE Journal
column "Guidance for Building
Operations During the COVID19 Pandemic" by Lawrence J.
Schoen, P.E., begins, "The HVAC
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systems in most non-medical buildings play only a small role in infectious disease transmission, including COVID-19." The column's HVAC
recommendations have also been
made by the CDC, ASHRAE and
OSHA and include better filtering,
longer operating hours and cleaning
HVAC equipment.
What is missing in most of the
published materials addressing
COVID-19 are evaluations of the
existing HVAC systems. It may
be implied, but this step is sorely
missing. The guidance should also
recommend verification that HVAC
systems have been properly maintained and that actual operation
meets the original design intent.
In many cases I have found that
the operation of HVAC systems
is determined by personnel with
limited knowledge of the system
design. Often, the staff technician
becomes the decision maker to
achieve energy savings and makes
the changes to HVAC operation.
Intervention by building occupants
has little effect where energy goals
are treated with greater interest and
urgency than occupant comfort,
health and productivity.
It is not appropriate for HVAC
technicians to unilaterally make
changes to the HVAC system without
a review by a competent HVAC engineer, preferably one with operations
experience. There is a true need for
an inspection process for HVAC ventilation operations. The ill effects of
modifying HVAC operation on people is menacing and hard to detect.
It would be interesting to know if
other HVAC engineers have encountered similar circumstances.
Now we have the crisis of COVID-19.
Locations with poor IAQ plus a virus

SEPTEM BER 2020

are a hazardous combination. Are
ventilation systems operating properly
and capable of providing a healthy
indoor environment? Verifying that
the HVAC system is operating as
designed is a necessary first step.

Michael A. Miller, P.E., Fellow/Life Member ASHRAE,
West Monroe, N.Y.

The Author Responds
Michael, thank you for making
these important points, which I
agree with. Since I wrote the column, several well-researched
reports have been released demonstrating COVID-19 transmission in
the absence of what I consider a minimally effective HVAC system.
I still believe the HVAC system
usually plays a small role, provided
there really is one in place that is
properly maintained and operated,
with amounts of outdoor air, filtration and room air distribution meeting a code or standard for the space
occupancy. My column, ASHRAE's
Epidemic Task Force (ETF) and other
published guidance from authorities, as you state, make further HVAC
recommendations. Avoiding dense
occupancy, using social distancing
and masks remain critical.
Evaluating and correcting existing
systems, as you emphasize, is essential, especially for buildings restarting
after a period of shutdown. Saving
energy is a lower priority than saving lives and good health at any time,
and especially during the pandemic.
Reopening guidance should prioritize
equipment checks and verification of
system performance.
Details to check include air delivery per person and correcting rooms
that receive minimal or no airflow.
The latter happens due to mistakes
such as moving or adding walls
without HVAC system changes, fire

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ASHRAE Journal - September 2020

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