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Technical can maintain high hygiene standards , safeguarding both products and clients .”
TYPES OF UV-C APPLICATIONS IN HVAC SYSTEMS Erasmus distinguished between mechanical and added ventilation UV applications : “ Mechanical ventilation UV involves integrating UV-C into existing HVAC systems , typically behind evaporator cooling units , to sterilise circulating air . Added ventilation UV is used in areas with limited mechanical ventilation and high occupancy , requiring additional ventilation and sterilisation through units equipped with fans .”
A common mistake is placing UV-C lamps only in coil areas of HVAC systems . While this can help with moisture and mould control , a comprehensive approach involves addressing multiple areas :
• Coil area : Moisture and mould build-up are common here . UV-C can prevent growth and maintain cleanliness
• Filter bank area : Care must be taken to avoid UV exposure to certain filter materials like HEPA filters , which can degrade . More durable filters , like washable pre-filters , can withstand UV exposure
• Air mixing chamber : Installing UV-C in large air mixing chambers can effectively sterilise incoming and return air
• Ducting : UV-C can be installed in return air ducts and supply air ducts to prevent mould growth and maintain clean ducts . Placement at the beginning of the ducting ensures maximum effectiveness and minimal bio-load build-up
By strategically placing UV-C fixtures in these areas , HVAC systems can achieve thorough and Positive Pressure and UV Installation .
One effective approach to maintaining air quality is creating positive pressure zones , with extraction through bathrooms or exit points . “ To implement this , you can install UV fixtures at accessible points in the ductwork , enhancing the system ’ s overall efficacy .”
Erasmus offered some further tips :
• A crucial step in managing your HVAC system is proper labelling and mapping . Diagrams and summaries of different areas , such as mixing chambers ( A to E ), help in visualising and understanding the system ’ s layout . This practice is particularly useful when deciding where to install UV fixtures .
• When it comes to fixtures , 99 % of the time , intercooler units for ducting and fresh air ducts are used . These fixtures are typically not available locally and may need to be imported . The variability in duct sizes means that a standard fixture may not always suffice ; sometimes , a single small lamp on one side of the duct won ’ t be effective .
• For cooling coil areas , it ’ s vital to provide accurate dimensions and velocities to the supplier . This information helps in recommending the correct UV unit for installation , ensuring efficient coil cleaning and maintenance cost reduction . UV units can prevent mould buildup , commonly mistaken for dirt , improving overall hygiene .
• To ensure proper UV coverage in coil areas , measure the area accurately and assess the air velocity . The UV fixture must be capable of handling the required volume , which is usually measured in cubic meters per second . Durable aluminium powder-coated fixtures are commonly used , equipped with reflectors and designed for different mounting needs .
Duct units are crucial for supply or return air ducting . It ’ s essential to choose the right unit based on duct shape and size . Extension arms ensure the lamp is positioned centrally within the duct , maximising effectiveness . Safety inspection windows allow for visual checks , confirming the unit ’ s operation .
PRACTICAL INSTALLATION TIPS
• Extension arms : These are necessary to position the UV lamp at the correct depth within the duct
• Inspection windows : These provide a simple way to verify if the UV light is functioning without needing to open the duct
• Power supply : Ensure a nearby power point with at least a 5-amp plug to power the UV unit .
• Plenum chambers : In cases where direct access is difficult , plenums can be built over return vents to facilitate proper installation .
“ By focusing on these aspects , mechanical engineers can effectively incorporate UV fixtures into HVAC systems , enhancing air quality and operational efficiency . This approach not only improves system performance but also reduces maintenance costs and extends the lifespan of the HVAC components ,” says Erasmus .
The remainder of this long and insightful presentation can be found online . RACA
“ By strategically placing UV-C fixtures in these areas , HVAC systems can achieve thorough and Positive Pressure and UV Installation .”
www . refrigerationandaircon . co . za RACA Journal I August 2024 43