HVAC can play a role in the transmission of COVID-19 and its possible changes to reduce the transmission.

It is believed that the infection can be transmitted from individual to-individual, no doubt through close contact with an infectious individual, or contact with droplets from an infectious individual’s cough or sneeze. At the point when an individual tainted with virus coughs or sneezes, pathogens can be encapsulated within droplets of fluid and released into the air. Droplets are believed to be in the air for hours and be entrained into HVAC systems.
Heating Ventilating and Air Conditioning systems are available in many formats. Basically it is a recycling framework where outside air is included consistently while a similar proportion is depleted simultaneously. The rate of outside air differs according to the different HVAC formats. Before the circulation and distribution of air, the air is filtered and moved using fans.
The droplet of an infected individual could show up in a consumed space which would incorporate ducted air pathways, numerous changes in course and air speed, and different affected surfaces including air filters, fans, dampers and grilles. There is a decent probability that a virus particle would affect, entrain and dry on a surface.
There are various measures that can be taken into consideration to reduce the transmission of virus through HVAC System

• Maintenance Regimes and Essential Safety Measures
• Cleaning, Disinfection and Sanitization
• System Commissioning and Operation
• Outside Air Rates
• Air Filtration and Cleaning Options

The danger of well-kept and maintained HVAC framework in a business building causing transmission of the COVID-19 are comprehended to be low. There are some measures that building proprietors and administrators can take to additionally decrease this transmission is elaborated below:

• It is imperative to have good housekeeping and maintenance schedules. Air conditioning support ought to be completed as endorsed by the recognized standards and guidelines and maintenance techniques ought to be clung to.
• Building administrators ought to meet with services providers if measures are being considered to block or limit support professionals from accessing building.
• It is essential to guarantee that HVAC frameworks have been appropriately authorized and are working effectively. Check the outside air rates and controls to affirm that the outside air rates are being accomplished as an essential necessity and ideally if possible increasing the outside air rates.
• Inner moistness should be preferably within the range of 40-60% RH.
• To reduce or lessen the transmission of infection through HVAC systems, it is imperative to check the current air filtration type and condition and updating or supplanting the channel media to F7 – F9 grade in lieu of the fan capacity limitations.
• HVAC Cleaning or sterilizing of the framework is required if:
• With approved methods and chemicals, air channels and filters ought to be changed, and cooling and heating coils can be cleaned and purified.
• HVAC framework containing induction type units or chilled beams can be cleaned and sanitized too.
• Most features and surfaces in HVAC frameworks can’t be physically cleaned regularly.
• If the HVAC system is not explicitly designed for fogging or fumigating treatment then it is prescribed that it should not be done for typical offices and standard HVAC. Hence it is imperative to design the HVAC framework well so that these issues doesn’t arise in the future.
• Considerations for improving humidity control are:
• Keep humidity between 45 and 55 % RH where possible and control temperatures between 21 and 24°C
• Monitor the humidity in the space and improve control – Building Management and Control Systems can have humidity sensors added to room temperature sensors or return air duct temperature sensors. For enhanced control algorithms to help control and balance humidity and temperature in existing HVAC configurations these inputs can be used.
• Review the existing Air Handling Unit configuration – Some units equipped with heaters can potentially be modified to easily de-humidity without major equipment upgrades. A control strategy change may be all that is required to de-humidify.
• Enhance the existing Air Handing System design – Modular humidification units can be added to help increase humidity. This is particularly important in many Australian climates in winter weather conditions where outside air has very low humidity). Good selection, control and maintenance management of these humidifiers is required to ensure effective operation and system performance.
• Upgrade and improve ducted fresh air into units by reviewing the source of outside air, add and improve outside air filtration and consider outside air pre-cooler units.
• Seal penetrations in the building fabric to reduce moisture ingress.
• Rebalance air systems where practicable to positively pressurise spaces where possible (unless a specific pressure regime exists).

With approved methods and chemicals, air channels and filters ought to be changed, and cooling and heating coils can be cleaned and purified.
HVAC framework containing induction type units or chilled beams can be cleaned and sanitized too.
Most features and surfaces in HVAC frameworks can’t be physically cleaned regularly.
If the HVAC system is not explicitly designed for fogging or fumigating treatment then it is prescribed that it should not be done for typical offices and standard HVAC. Hence it is imperative to design the HVAC framework well so that these issues doesn’t arise in the future.

HVAC Systems can be used to limit the spread of covid-19, yet there is just so much that can be accomplished beyond these above measures. The role of HVAC frameworks in controlling the transmission of disease ought to be viewed as a piece of a more extensive multi-modular infection control technique in structures. HVAC BIM Modeling plays an important role, wherein the design and detailing of the HVAC systems can be done by taking into considerations such transmission of infectious diseases and easy maintenance and sanitization of the systems.