D&J Contractors, Inc. has been receiving inquiries regarding the effectiveness of UV disinfection systems against COVID-19 (corona
virus). We believe the best approach is to be as transparent as possible and to explain the fundamentals and variables that play a factor in inactivating corona virus and other pathogens with UVC germicidal technologies.
Our APCO-X and Residential UV systems are tested and validated against bacteria, viruses, mold & fungus. The UV systems have been tested and achieve up to a *99.999% reduction on microorganisms. There are a number of factors that need to be addressed in order to determine efficiency, these include but not limited to, the application, such as surface or air disinfection, air velocity and temperature, recirculation rates, and dwell time, as well as the specific biological target. The UV systems are installed in the HVAC unit and/or ductwork and are designed to disinfect surfaces and the air as it circulates through the ventilation system. UV dosage can be measured in several ways including microwatts per second/centimetres2 (μWs/cm2).
Every microorganism requires a specific UVC dosage for inactivation including coronavirus. UV disinfection has been employed for decades in water treatment; these microwatt values have been used for reference to gauge UVC efficiency against a large cross-section of microorganisms. While our whole house/office UV systems have not been specifically tested against coronavirus, they have been tested and proven effective against similar pathogens, some that require an even greater dosage for inactivation
than corona virus.
UV disinfection systems for room, surface & HVAC are an ideal proactive measure to
complement filtration. Microorganisms, particularly viruses, are so small that filters
are mostly ineffective. The UV systems have also been shown to reduce problematic
molds and pathogens that are found within the HVAC system and drain pan that would
otherwise be introduced and distributed throughout the envelope of the building.