In modern buildings, central air handling units (AHUs) filter and clean the air, which is then distributed through ducts to rooms, offices, classrooms, and halls.
Some air handling units partially or entirely recirculate the used air from these spaces, which can reintroduce a portion of the viruses and bacteria back into the indoor air, potentially contributing to the spread of illnesses. Even in systems that use only fresh air, the microorganisms that settle in the ductwork make it necessary to disinfect the supplied air.
HEPA and other filters used in air handling units are effective at capturing larger particles, but they cannot retain viruses smaller than 0.3 microns. This is where custom-designed UV-C / germicidal lamp systems provide a solution: installed within the air handling unit or ductwork, they effectively destroy airborne pathogens.
UV-C / Germicidal Effect
The UV-C / germicidal radiation range below 280 nm is highly effective in destroying microorganisms such as bacteria, viruses, and molds living on surfaces or in the air. (These are among the most common pathogens that regularly appear in our daily lives.)
All of these can be eliminated with the appropriate dose of UV-C light.
Advantages of UV-C Technology
- Effectively destroys microorganisms
- Does not use chemicals, therefore it is completely environmentally friendly
- No by-products are generated
- Cannot be overdosed
- Pathogens cannot develop resistance against UV-C radiation
- The dose can be precisely calculated, making it possible to install and operate only the necessary resources
For general-purpose rooms, an efficiency of at least 90% is required. In areas requiring higher sterility (food industry, hospitals, operating rooms, pharmacies), the target should be 99% – 99.9% – 99.99%.
Hollandimpex Kft has more than 10 years of experience in UV-C technology. We undertake the calculation and commissioning of UV-C lamp systems not only for new investments, but we can also design them as retrofits for existing HVAC systems. With the expertise of our colleagues and our specialized design software, the required dose can be calculated precisely. It can be determined which UV4AIR unit needs to be installed in a given air handling unit or air duct of specific size and capacity to achieve the required level of germicidal efficiency.
Advantages of the UV4AIR System
- Custom-designed to match the given parameters
- Can be retrofitted to already operating systems
- Does not produce ozone
- Can be used in a closed system, ensuring continuously disinfected air
- More effective in air ducts and air handling units than any other method
- One-time installation, does not require continuous supervision, only annual maintenance
Most Common Areas of Application:
- Office buildings
- Shopping centers
- Healthcare institutions
- Retail stores
- Food industry
- Manufacturing plants
- Fitness centers
- Nurseries, kindergartens, and schools
Appropriate Efficiency, Custom-Designed Equipment
The UV-C dose is a function of irradiation intensity and exposure time, measured in µWs/cm² or µJ/cm². With a given lamp, a higher dose can therefore be achieved by increasing the exposure time.
The efficiency of UV-C germicidal units is determined by the dose they are able to deliver to the treated medium — in this case, to the microbes suspended in the air being transported. The required exposure time depends on the flow velocity of the particles, which is clearly defined by the dimensions of the air duct and the air handling unit’s airflow capacity.
Expected Results
The International Ultraviolet Association (IUVA) has developed a classification system that categorizes UV-C germicidal units into grades based on the radiation dose they provide.
In air handling units and air ducts, the generally required grades fall between URV 14–17.
The UV germicidal systems built by Hollandimpex Kft are typically designed for general applications to achieve URV 15–16 levels, which correspond to a minimum dose of 4,000–5,000 µJ/cm².
For common pathogens, this results in a 2–3 LOG reduction in colony-forming units (CFU), which means a 99–99.9% level of disinfection.
The table below also indicates the degree of pathogen inactivation at different dose levels; the stated doses always represent the minimum required value for the given level (e.g., URV 10 = 500–999 µJ/cm²).
