PETALING JAYA: Having good ventilation at business premises can help reduce contaminants in the air and curb the spread of Covid-19, say health experts.
Universiti Malaya public health medicine specialist Prof Dr Victor Hoe said good ventilation would not only prevent infectious diseases and reduce sickness, but also improve morale and productivity.
Dr Hoe said people are usually enclosed inside buildings without fresh air.
“They are recirculating the air and the reason is to conserve energy as the cost of cooling fresh air is higher than recirculating cool air,” he said when contacted.
He added that businesses should not hastily decide to change their ventilation system without consulting with experts.
“While many people have recommended opening windows to allow fresh air into the building, this will alter the air flow. The air from the outside is usually warmer than the air in the building.
“Mixing cool and warmer air will generate moisture and this will increase the chances of fungal formation in the ventilation system.
“Fungal issues are as bad if not worse than the Covid-19 pandemic. The other issue with moisture is that it will affect electronic systems,” he said.
As such, to ensure good ventilation, Dr Hoe said the air exchange per hour (ACH) should be increased.
“In a normal office that uses a centralised air conditioning system, the ACH is usually between four and six air changes in an hour.
“At this rate, the time required for removal of 99% of the contaminants in the room is between 69 and 46 minutes.
“To improve the ACH, we can install Hepa (high-efficiency particulate absorbing) filters which can increase the ACH to 10, reducing the time it takes to remove contaminants from 46 to 28 minutes,” he said.
Dr Hoe reminded businesses that ventilation improvements would only reduce Covid-19 risk but could not eliminate it entirely.
Medical Practitioners Coalition Association of Malaysia president Dr Raj Kumar Maharajah said having good ventilation is not just good for business entities but also for homes.
He said a good ventilation system could help prevent virus particles from accumulating in the air.
“Good ventilation, along with other preventive actions, like staying 2m apart and wearing masks can help prevent you from getting and spreading Covid-19,” he added.
To have better ventilation, Dr Raj suggested that there should be, among others, an increase in ventilation and enhanced air exchanges, as well as exhaust fans.
For those in enclosed spaces, he recommended they consider having portable air cleaners for localised air cleaning.
American Society of Heating, Refrigerating and Air-Conditioning Engineers (Ashrae) Malaysia chapter president Ng Wen Bin said ensuring proper ventilation with outside air could help reduce the concentration of airborne contaminants, including viruses, indoors.
“Proper ventilation also reduces surface contamination by removing some virus particles before they can fall out of the air and land on surfaces. However, by itself, increasing ventilation is not enough to protect people from Covid-19.
“But when used along with other best practices recommended by Ashrae and others, increasing ventilation can be part of a plan to protect people indoors,” he said.
As most schools, offices, and commercial buildings have air conditioning and mechanical ventilation (ACMV) systems with filters, Ng said increasing ventilation and filtration was usually appropriate.
But due to the complexity and diversity of building types, sizes, construction styles, ACMV system components, and other features, he said a professional should interpret Ashrae guidelines for their specific building and circumstances.
“Increasing ventilation may not always be possible or practical. In such cases, the effective rate of ventilation per person can be increased by limiting the number of people present in the building in general, or in specific rooms,” he said.