Airborne infections are carried by microorganisms like bacteria, fungi and viruses that are invisible to the naked eye but can be easily transmitted through infected surfaces, unhealthy environments or from infected individuals and can cause serious health issues. According to WHO, the most effective way to prevent the spread of airborne infections in the indoor environment is good ventilation that swaps indoor and outdoor air with more air exchanges per hour. Air-conditioned spaces have zero ventilation causing the same unhealthy and infected air to circulate inside the space, the harmful microorganism not just remains within the space but also increases. Thus it is very important to control the exchange of air especially in fully air-conditioned hospitals, offices, malls, hotels, gyms, theatres, food industries, etc.
Bacterial and viral microbes account for 60-80% of indoor air quality problems. An Air Handling Unit (AHU) re-condition and circulate air as part of a heating, ventilating and air-conditioning system (HVAC ). The basic function of the AHU is to take in the air from outside then re-condition it and supply it as fresh air to a building. Fungal contamination of air handling units ( AHUs) is a common phenomenon in buildings with central heating, ventilation, and air conditioning (HVAC) systems and is a possible source of contamination for occupied spaces and often contribute to building-related diseases. Recently, the use of Germicidal ultraviolet irradiation (UVGI) to disinfect indoor environments has gained popularity to control infectious diseases in air-conditioned environments. UVGI is a method of disinfection that uses short wavelength ultraviolet light (UV-C) to inactivate microorganisms and pathogens. Fundamentally, UVGI make use of UV light with sufficiently short-wavelengths to decontaminate air, surface, and water.Several studies have determined the effectiveness of UVGI in reducing fungal and viral contamination within AHU.
According to the 2015 ASHRAE Position Document on Filtration and Air cleaning, “ effectiveness of a UVC system to inactivate microorganism in the air and /or on surfaces has been amply demonstrated; the best results were obtained for the long-term irradiation of downstream coil surfaces to avoid fungal amplification on the wet surface.” Biofilms on coils fins can adversely affect the transfer to/from the air stream. Lack of mechanical cleanings will result in loss of up to 25% of cooling capacity in as little as five years. UVGI system can help restore an AHU to its original operating capacity. The reason for installing UVGI in Air Handling Units of HVAC is to overcome the following common problems encountered with Air conditioning and Refrigeration systems, commissioned without any UVGI device
- Increased electricity consumption– Moisture condensation around the cooling coil leads to the growth of moulds, algae, mildew, bacteria and viruses. This results in the reduction of the heat transfer efficiency and airflow of the AHU which in turn increases the power consumption
- Deteriorating Indoor Air Quality (IAQ)– The contamination from the workplace and the contamination of the air while passing over the coil deteriorates the IAQ leading to Sick Building Syndrome (SBS) and increased sickness among the inhabitants of the building. In case of cold storages, it can cause contamination and deterioration of food product
- Increased operational and maintenance cost– Contaminated coils will reduce the efficiency of AHU and difficulties are experienced to maintain clean and contamination-free air passage.
An AHU with the right combination of UVGI features installed can work as a blessing when it comes to the control of transmission of disease and infection. Direct exposure to UV lamp can be hazardous for human but in controlled exposure, right conditions and systematic installation it can be a bonafide source to kill viruses and bacteria by disrupting their DNA & RNA, making them unable to reproduce. UV lamps have some impeccable attributes that can give wonderful results if used systematically and they are extensively used in AHU for reducing bacterial load on the cooling coil and prevent the formation of mould and algae. Several benefits of installing UVGI devices in AHU are as follows:
- It prevents microbial colonisation on HVAV coils and drainage trays
- Kills bacteria, viruses and germs 24/7 throughout the coil
- It will control other allergens
- It will fight against favourable bacteria and mould breeding ground environments to reduce the formation of biofilm
- It will reduce smells and odours
- UVGI for AHU promotes healthy living and operational efficiency
- It will remove volatile organic compounds
- Maintenance requirements will be reduced
- It will help in maintaining a cleaner AHU unit thus increases its efficiency to save power
- It will reduce coil replacement frequency and maintenance expenditure
- There will be a reduction in building-related illnesses
- There will be a reduction in energy consumption
For the safety of installing UVGI devices within AHU make sure it will meet UL 1995 standard 5th edition, this international UL standard seeks to eliminate variations in equipment design that might lead to accidental exposure to UV. UVGI devices when installed in a building AHU system will work continuously 24/7 and the overall result is the purest and high quality of air inside the premises and increased system’s life and efficiency
MG Cooling Solutions a leading HVAC enterprise that will help you to improve your building’s indoor air quality with the best UVGI purification solutions and smart ventilation. We are a qualified HVAC engineering firm that will provide the best measures to protect your building from COVID-19