INDOOR AIR QUALITY
Shining a light on IAQ
Aermec’s Clifford Saunders takes a look at ultraviolet light and its benefits in HVAC systems.
T
he global pandemic has thrown the spotlight onto the subject of indoor air quality (IAQ) particularly in commercial buildings. Buildings face a myriad
of IAQ issues ranging from energy efficiencies to comfort levels. But Covid-19 is now encouraging building owners and managers to give ultraviolet light in HVAC systems careful consideration. Effective ventilation can play a critical role in controlling the spread of airborne viruses in spaces. The government is actively encouraging the opening of windows to keep internal environments well ventilated, but once the winter months take hold that may not be such a good idea. Which is why attention is now focusing on other solutions and ultraviolet light (UV) and its effectiveness in killing viruses is being heralded as a possible solution that could improve IAQ whilst making environments safer. UV is not a new technology its ability to sterilise bacteria became known in 1878. Most pond owners use the technology to keep algae and other contaminants at bay whereas in the health sector and clinical environments, UV is used for in many environments; cleaning hospital floors using robotised equipment for disinfecting operating rooms, patient treatment areas, wards as well as the cleaning of laboratories. There are many hospitals like The Walton Centre in the North West taking advantage of robotised UV light systems to ensure environments are de-contaminated using a robust deep clean technology. UV is used for sanitising rooms that have been used to
quarantine infectious patients. This has prompted health estate managers to start questioning other parts of their hospitals’ infrastructures namely air conditioning systems and the impact on patients, front-line care givers as well as other employees and any visitors.
Although hospitals are places where a much higher
concentration of pathogens can accumulate than in the average building or work place commercial buildings still carry similar risks. Pathogens can travel in air which can be affected by many factors; temperature, humidity, frequency of doors opening and closing and room occupancy. IAQ concerns has led to increased attention on HVAC systems and the steps that can be taken to improve their design to minimise employees’ exposure to pathogens. Many health estate managers and building owners are now faced
14 November 2020
having to design safe environments for employees that are not able to work remotely. Plexiglass screens are becoming a common sight along with accessible hand sanitising stations. We breathe in various types of micro-organisms all the time; most can be tolerated with no specific health care issues. But, some viral infections though, such as MERS, SARS and Coronaviruses can easily spread and cause serious harm. One way of managing the spread of viruses is to inactivate them. This can be achieved by breaking them down biologically and one of the most effective methods is the use of UV.
UV has been used for decades to disinfect industrial surfaces, sanitise drinking water, banks regularly use it to disinfect money and in China, buses can be seen lit up at night as the blue light gets to work decontaminating them.
Disinfecting the air stream As airborne infections travel through the air stream, they are disinfected by the high intensity UV light. UV offers a solution for eradicating harmful components in the air that we breathe.
North American studies have highlighted the benefits of UV technology and how it can destroy up to 97.7 per cent of pathogens and suggested that UV sanitising devices could be used across hospital environments to help minimise the spread of bacteria from workers smartphones and tablets for example. Many of the HVAC industry’s manufacturers are starting
to incorporate the technology in air conditioning systems. ASHRAE (American Society of Heating Refrigeration and Air Conditioning Engineers) has created a task force to assess the effects of HVAC systems and the transmission of viruses in buildings, suggesting that changes to a building’s operation could help reduce the risks of pathogen transmission. It has made available a number of position documents relating to the benefits of UV and the transmission of infectious aerosols. Researchers at the University of Oregon’s Biology and
Built Environment Centre have conducted extensive studies and outlined a number of steps buildings owners can take to mitigate transmission and protect a building’s occupants, including exposure to ultraviolet light, which can reduce the ability of some viruses to survive.
www.acr-news.com
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