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Air Conditioning System Air Filters
27 March 2020

John Herbert, hong kong energy saving expert, BEAM expert
John Herbert

In Hong Kong the HVAC air filters used in typical air conditioning system equipment, for example air handling units and fan coil units barely conform with the standard MERV 6. Normally, these air filters are constructed from aluminium wire mesh to comply with the non-combustibility requirement.

Environmentist John Herbert said that that type of air filter is hopeless for today's threat. A respiratory droplet with a diameter of approx. 5-15 micrometres, it is microscopic droplet that floats indoors for upto three hours, carrying thousands of viable virus particules.

wire mesh filter, particule sizes, covid-19, bacteria, sporesTypically Hong Kong wire mesh air filter

The COVID-19 virus is microscopic approx. 6 nano-metres, but the air filter does not need to stop the virus, it needs to stop the water droplet carrying the virus particules.

To be effective HVAC air filters should be able to arrest particules down to 3 micro-meters, should be standard MERV 13 or greater to be able to arrest and stop water droplets circulating in the air. And HVAC technicians need to exercise caution handling and cleaning these washable type air filters.

particule sizes, covid-19, bacteria, sporesRelative size of particules, bacteria, and mould spores || click on image for larger image

About the Author

John Herbert is a veteran chief engineer with more than 30 years international engineering experience, educated in the United Kingdom, he has worked in the United Kingdom and then across Asia for more than two decades engaged by international and local companies. He is a Hong Kong Registered Energy Assessor (REA), a BEAM Professional, and stationed in Hong Kong.


tags: health, safety, coronavirus, covid19, buildings, drainage, hygiene, precaution, u trap, p trap, condition survey, report, piping, plumbing, drains, sewerage

date: 15-04-21
kelcroft consultants hong kong