Sensory Library Design: Responding to a Pandemic's Impact on Built Environments

What We Breathe
Public health experts have underscored that
COVID-19 is mostly spread by respiratory
droplets released when people breathe, talk,
cough, sneeze, and sing (which is why it’s so
important to stay physically distant from one
another). Being with people from other households
in interior spaces is always a risk in an
ongoing pandemic, but this risk can be reduced
by breaking the transmission pathways of aerosolized
virus. ASHRAE, a global society with the
mission to, “serve humanity by advancing the
arts and sciences of heating, ventilation, air conditioning,
refrigeration, and their allied fields” has
published position papers about safe engineering
practice for the built environment. In ASHRAE
Position Document on Infectious Aerosols,
ASHRAE states, “Ventilation and filtration provided
by heating, ventilating, and air-conditioning
systems can reduce the airborne concentration
of SARS-CoV-2 and thus the risk of transmission
through the air” (ASHRAE 2020).
Mechanisms to increase the health of indoor air
fall into five basic categories:
1. Dilution. Dilute the air’s potential viral load
by introducing more outside air, improving
the effectiveness of air distribution
systems, and reducing the mixing of air in
occupied spaces (e.g., through the use of
displacement air systems such as under
floor air distribution). Evaluate your energy
recovery system’s installation and operation
to ensure there is no cross-contamination
between air being exhausted and outside air
coming into the building.
2. Relative Pressurization. Control/adjust
relative pressurization between building
spaces to avoid cross-contamination
between zones.
3. Improved Filtration. Use highly-efficient
particle filtration (enhanced beyond
code minimums). This strategy can be
incorporated into central air handling
systems as a filter replacement or upgrade.
Another option is to use unitary air scrubbers
with HEPA filters, which can be located within
an occupied space.
4. Mechanical Disinfection. Utilize ultraviolet
(UVC) lighting systems above head height
along room perimeters, within air handling
unit casings and/or ductwork, or bipolar
ionization in occupied spaces or within
ducted systems.
5. Optimized Relative Humidity. Make
provisions to control relative humidity to
stay within a range of 40%-60%. This tactic
typically involves adding humidification to
central systems or spaces.
Libraries should also have an emergency
response plan to maximize outdoor air ventilation
and improve central air and HVAC filtration
(using MERV 13 filters at a minimum, with MERV
15 filters preferred). Consideration should be
given to running systems 24/7 if possible and to
maintaining a range of temperature and relative
humidity that reduces the lifespan of bacteria
and viruses. Recent best practices also suggest
a full building flush using the central air handling
systems before and after occupied hours when
outside air conditions are acceptable. Because
many of these measures will have an appreciable
impact on energy use, we recommend
consulting a mechanical engineer to ensure that
the building’s heating, ventilating, and air conditioning
systems are engineered, operated, and
maintained to optimize safety without sacrificing
personal comfort—during the pandemic and,
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