The ventilation system and the good quality of air in all types of buildings, such as the workplace, business premises, education institutions, places of worship and residences are among the important strategies to contain the spread of Covid-19.

Therefore, Health director-general Dr Noor Hisham Abdullah advised all parties to refer to and adopt the ventilation system guides suggested by the Health Ministry (MOH), Human Resource Ministry (MHR) and the World Health Organization WHO).

He said generally there are three types of ventilation systems, namely natural ventilation, air cooling system without mechanical ventilation and air cooling system with mechanical ventilation (MVAC).

For natural ventilation, the risk of Covid-19 spreading and other airborne diseases is low but there are methods to improve ventilation and movement of air by opening windows and using fans to improve ceiling ventilation.

“For air cooling system without mechanical ventilation, apart from opening windows and using fans, it is recommended to install exhaust fans as well as ensuring small window openings to keep the temperature at between 23 to 26 degrees Celsius,” he said in a statement yesterday.

This guideline on ventilation to reduce Covid-19 transmission risk is released by Singapore

In the usage of MVAC system, Noor Hisham suggested the system control and component be maintained and function according to its design, including air filter seals which should be monitored and replaced according to the recommended frequency.

Apart from that, to improve clean air from outside through the air damper opening or deactivating Demand Control Ventilation (DCV) and make the MVAC system operate with maximum outdoor air intake for two hours before and after occupying the place.

“Apart from that, upgrading the air filter in the existing air intake unit to at least MERV-14 as well as using air purifiers with HEPA technology.

For MOH and MHR Indoor Air Ventilation and Quality Guidance Manual for Residential/ Non-Residential/ Public Area Settings During the COVID-19 Pandemic, one can refer to the link at https://www. dosh. gov. my/index.php/ms/ and to the WHO Roadmap to Improve And Ensure Good Indoor Ventilation in The Context of COVID-19, March 2021 at https://www.who.int/publications/i/item/9789240021280.

- Bernama