Health director-general Dr Noor Hisham Abdullah said this in calling for all quarters to refer and adopt the ventilation system guides recommended by the health ministry and the human resource ministry, as well as the guidelines from the World Health Organization (WHO).

He said generally there are three types of ventilation systems – 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 the movement of air by opening windows and using fans to improve ceiling ventilation.

“For air cooling systems without mechanical ventilation, apart from opening windows and using fans, it is recommended to install exhaust fans and have small window openings to keep the temperature at 23°C to 26°C,” he said in a statement today.

For premises using the MVAC system, Noor Hisham said the system control and components must be maintained and made to function according to its design, while ensuring air filter seals are monitored and replaced according to the recommended frequency.

“Then deactivate the Demand Control Ventilation (DCV) and let the MVAC system operate with maximum outdoor air intake for two hours before and after occupying any premises.

“This will help to improve the clean air from outside through the air damper opening,” he added.

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

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