Feature
the duct . This will ensure that uncontaminated air is supplied . The UV Air Purifier is able to deactivate approximately 95 % of viruses in the Corona category in a typical room ( 4.5 x 4.5m x 2.4m ) in less than an hour . The performance depends on the diffuser size , neck pressure and room size . The combination of air purification , clean air supply and low draft rates makes the UV Air Purifier the answer to the threat of viruses in a space ,” he says .
Portable standalone units use an enclosed UV-C light and a fan to suck air over the light . In this way air contaminated with viruses and fungi is deactivated . Rickard ’ s UV Air Purifier is integrated with the diffuser allowing for a clean open space for the occupant
“ We ’ ve sized everything according to the volume of air that is induced through our diffuser , when it is supplied with air at normal pressures . It can treat the air of a typical room in 30 to 60 minutes under these conditions .
“ By supplying fresh air through our diffusers we provide a dilution effect of the virus as well . We designed this for Covid , and it has similar application for sick buildings , hospitals , and a normal office environment . There is a faceplate over the diffuser to induce the air over the UV light and ensure that the UV levels are below 0.2 microwatts per centimetre squared at the occupant level . We have a certified laboratory meter to test and ensure it ’ s safe ,” says Rickard .
The system can function either to retrofit a building or as part of a new design , he says .
TECHNOLOGIES AVAILABLE TO ENGINEERS TO INCLUDE IN THE ORIGINAL DESIGN OF A BUILDING
Most buildings recirculate the air through the building to some degree , with about 30 % fresh air being the minimum requirement and 70 % recirculated . Rickard advises removing particulates using HEPA filters , though UV-C lamps can also be put in the ducting sized according to the volume air and velocity through the ducting .
“ There are some new products coming out in the UV-C space , such as large ceiling fans for industrial applications and other bigvolume areas , with the blades fitted with UV-C lights in the back . There are also diffusers that treat supply air with plenum boxes and a UV-C light fitted inside each . However , it ’ s actually easier and more cost effective to fit a UV-C light near the centralised air unit upstream to treat supply air ,” says Rickard . “ We believe our unit is unique as it treats the air in the room rather than just the supply air .
“ When it comes to the installation of UV-C lights or HEPA filters to purify the air in a duct the designer needs to understand
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RACA Journal I February 2023 www . refrigerationandaircon . co . za