Bryair decided to conduct an experiment before Christmas.
Seeing as we have been pushing UVC for improving Indoor Air Quality, it would have been hypocritical if we at Bryair had not installed UVC within our office.
Our AC system has now had UVC installed since August 2020 and we have continued regular maintenance procedures every three months, ensuring filters are kept clean.
We have a split AC system with two cassette units installed within the ceiling void. These cassette units are in the same room and spaced on 3.5m apart.
Bryair is fully behind the fact that UVC offers so many health benefits as well as helps to save money by reducing energy bills. I was in the office when the UVC was installed and I saw the UVC coloured light. But once the cassette was closed, that was it, you can no longer see anything happening.
- How clean are they?
- Are they doing a thorough job?
- Are the tools used adequate to perform the task?
- Is the cleaning spray toxic?
So, seeing is believing, right?!
This bring us back to our experiment.
The decision was made to perform the experiment within our office. We decided we would turn the UVC off in one of our cassette units in November. We then purchased contact plate petri dishes and conducted a swab test in January. Each of the contact plates were pushed into the coil fins of the cassette units in the office and sealed up and left over the weekend.
As you look at figure 1 below, the clean petri dish on the left was the one swabbed on the unit with UVC. The one of the right where you can clearly see mould growing was swabbed on the non UVC cassette.
Two and a half days after performing the swab tests, the result is conclusive. The contact plates have now been sent off to a lab to analyse what the mould contains. But this does prove what an efficient job UVC does.
Inhaling mould fragments or spores can inflame the airways, causing nasal congestion, wheezing, chest tightness, coughing and throat irritation. Prolonged exposure to high levels of mould can reduce lung function and cause chronic health problems such as asthma.
Evidence of mould forming on coils is representative that a biofilm has formed on the coil. The mould doubles in size every 4-6 hours and easily multiplies into a billion organisms in 12 days. As long as the mould is ‘alive’, it will keep growing. This biofilm continues to make the HVAC system less and less efficient as the biofilm grows.
Even a biofilm on the coil with 0.15mm thickness will reduce the efficiency of the AC unit and will require an extra 11% of energy to drive the unit to the same settings. As the units are not performing as well, the settings on the control units are often turned up to achieve the same thermal comfort which again takes even more energy to obtain the same results.
Installing UVC within the HVAC systems provide better health and wellbeing, increased employee productivity, less sick days, equipment sustainability, obtain BREEAM® credits, reduce Carbon Foot and save money on energy bills which have over the past 10 years risen sharply and will continue to do so as the government strive towards a carbon net zero by 2050.
Seeing is Believing!!
If you have a project you’d like to discuss, please contact us.
Figure 1: Petri dishes from experiment