Page 26 - Climate Control News April 2020

Residential Air Conditioning
Strategies to reduce airborne exposure
They capture and hold them within the matrix of the filter,” Camfil explained.
“High efficiency air filters (HEPA) can be in- stalled in HVAC systems, filtering out biological pollutants and particulate matter carried by the air-stream, preventing them from entering or re- circulating back into the room.
“As unfiltered air flows through the HVAC unit’s duct-work, the air filter captures and holds the airborne pollutants.
“For further risk mitigation of airborne patho- gens, it is recommended to upgrade or install the highest possible efficiency HEPA filtration (H13 or higher) in the existing ventilation system. This will improve your chances to avail an extra layer of protection against airborne pathogens.”
Virus containment at health care facilities and bio-safety labs is very much about control meas- ures and precautions for airborne exposure.
Camfil said measures include ventilation, pressure differentials, exhaust ventilation, air fil- tration and cleaning, ultraviolet and germicidal irradiation (UVGI) and even temperature and humidity control.
Air filtration solutions depend on the category of the risk when in application.
“High risk application needs air containment and filtration equipment of HEPA Class H13 or higher along with use of special personnel equipment and clothing, as well as a segregated air supply, among other precautions,” the state- ment said.
Camfil suggested using air cleaners for fast and easy retrofit in case of a sub-standard venti- lation system to improve air filtration.
“It is also a way to rapidly boost the air quality of an already good functioning system when there is an increased risk that demands even bet- ter protection,” the statement said.
RESPONDING TO CORONAVIRUS (COV- ID-19) fears, Camfil has issued a statement.
It provides advice on protection from infec- tions. “While most of us don’t have the power to make the air cleaner, there are some things individuals can do to reduce the effect of these infectious particulates in the air,” the state- ment said. “HEPA filters have been proven over decades across a wide range of healthcare fa- cilities and life sciences applications, control- ling the spread of airborne particles and organ- isms such as viruses and bacteria. Many professional engineering organisations recom- mend HEPA (high efficiency particulate air fil- ters) in hospitals, infection control clinics and other healthcare facilities to eliminate mi- crobes and other dangerous particles.”
“HEPA FILTERS CAN BE INSTALLED IN HVAC SYSTEMS.”
True high-efficiency particulate air (HEPA) fil- ters are measured at MPPS (most penetrating particle size) that means this is the lowest effi- ciency of the filter. For smaller or larger particles the filter will perform even better. MPPS is typi- cally between 0,1-0,25 micrometer in size.
“Bacteria and viruses are often smaller than that but typically attach themselves to larger particles. It’s also important to understand HEPA filters do not actively kill living organisms.
AHRAE GUIDANCE ON CORONAVIRUS
ASHRAE has developed an online resource to help address coronavirus 2019 (COVID-19) concerns with respect to the operation and maintenance of heating, ventilating and air-conditioning systems.
ASHRAE’s COVID-19 Preparedness Resources webpage provides a range of resources to building industry professionals including a long list of publications to provide guidance.
The organisation’s president, Darryl K.Boyce, said the recent escalation in the spread of coronavirus disease 2019 is alarming on a global scale.
“While ASHRAE supports expanded research to fully understand how coronavirus is transmitted, we know that healthy buildings are a part of the solution,” he said.
The Preparedness Resources page provides building owners, operators and engineers with guidance on how to best protect occupants from exposure to the virus, especially in relation to airborne particles that might be circulated through buildings’ HVAC systems.
Because small particles remain airborne for some period of time, the design and operation of HVAC systems that move air can affect disease transmission.
In order to reduce disease transmission, ASHRAE recommends dilution ventilation, laminar and other in-room flow regimes, as well as differential room pressurization, personalized ventilation, source capture ventilation, filtration (central or unitary) and UVGI (upper room, in-room, and in the airstream).
ASHRAE president, Darryl K.Boyce
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