Ultraviolet germicidal irradiation (UVGI) makes use of ultraviolet (UV) energy to inactivate viral, fungal, and bacterial organisms. Ultraviolet light is naturally present electromagnetic radiation that is approx. 10% of the total light produced by the sun. The wavelength of this light ranges from 10nm to 400nm and is divided into three sub-bands; UV-A (near), UB-B (middle), UV-C (far). UV light having a wavelength less than 290nm is considered to have “germicidal” properties. UVGI technology makes use of UV-C light to damage the DNA and RNA of microorganisms so that they lack the necessary protein required to replicate and got killed. The effectiveness of germicidal UV Light depends on the length of time, intensity, and wavelength of UV radiation a microorganism is exposed to.
Upper room UVGI is a method of disinfection that makes use of UV energy and it is located above people in the rooms they occupy. This kills the airborne pathogens in the environment where they are released. Upper room UVGI Systems provide air changes per hour that are similar to the introduction of clean air into the indoor environment.
How does upper room UVGI work?
Upper room UVGI Systems consists of luminaries with lamps installed that emit light in the UV-C range that is 100-290 nm and typically at 254 nm generated by low-pressure mercury lamps. The luminaries are designed with louvers that limit the light to a narrow region and are installed in the upper part of the room. When the air passes through the disinfection zone from airflow through the HVAC system, fans, or open windows it inactivating the infection airborne agents that reach the light. This keeps the lower part of the room UV- C free that minimizes the exposure to persons in the lower part of the room
Factors affecting the effectiveness of upper-room UVGI?
- Temperature – UVC lamps work effectively at 700 F (210 C) colder temperature can reduce their output
- Humidity – relative humidity should be controlled and it should be less than 60% for ideal upper-room applications and comfort
- Air mixing – upper-room UVGI requires air mixing to raise microorganisms into the UV field. Supply diffusers and return grills should be designed to promote ideal airflow patterns in the room.
- Upper room UVGI Systems and ventilation – UV + Ventilation up to 6 ACH are additive in microorganism deactivation in well-mixed rooms. Ventilation over 6 ACH reduces its effectiveness due to less inhabitant time of microorganisms in the UV zone
- UV Irradiance and dose – UV dose i.e., irradiance x time is based on the susceptibility of microorganism expressed in µW·s/cm2
Application of upper-room UVGI
An important location for UVGI is high-risk indoor settings, they are
- Crowded places, especially when the health status of the occupants is not known e.g., courtrooms, lobbies, homeless shelter sleeping areas
- Spaces where people take off their masks to drink or eat e.g., restaurants, cafeterias, break rooms
- Areas where it is tough to remain at least 6 feet apart from each other
- Area with an increased probability of sick people e.g., hospital waiting room, school nurse’s office.
- It is recommended in spaces with the insufficient HVAC system and where adequate natural ventilation can’t be maintained
Upper-room UVGI Systems are usually custom-designed according to the space in which they will be Installed. Once installed, the system will need a little maintenance. The upper-room UVGI got many applications to use in high-occupancy settings where unsuspected infectious persons may be present. This technology got many benefits that are low power usage, flexibility, and a high rate of air disinfection
MG Cooling solution understands the value of clean, healthy, and bacteria-free air, contact us for any kind of queries on HVAC or UVGI systems and how it is beneficial for your business. We provide easy installations and pocket-friendly solutions.