“It has been known that spending a lot of time working indoors, especially poorly ventilated ones, exposes workers to a higher risk of to Covid-19 infection. It is important for establishments to ensure adequate and proper ventilation which eliminates contaminated air and is thus a highly effective preventive measure against Covid-19,” said Occupational Safety and Health Center (OSHC) Executive Director Noel C. Binag, CE.

The DOLE’s OSHC and Bureau of Working Conditions developed the recently signed DOLE Department Order No. 224 series of 2020 or the Guidelines on Ventilation for Workplaces and Public Transport to Prevent and Control the Spread of Covid-19. “We cannot overemphasize that these ventilation guidelines must always be implemented together with minimum health protocols such as wearing face masks and face shields, social distancing, and frequent hand washing,” Binag added.

The DO No. 224 recommends maximizing natural ventilation through opening doors and windows in buildings whenever possible and to ensure that the natural air entering the workplace is free of contaminants. If natural ventilation is not possible or is inadequate mechanical ventilation through fans and air conditioning units must be used. The direction of the airflow should be considered in the layout of work stations to avoid person to person viral spread through airborne respiratory droplets.

For air conditioned workplaces the outdoor air supply should conform to the recommended breathing zone ventilation rates for general air dilution and comfort control. The ventilation systems must be run at least 30 minutes before and after the spaces are occupied.


In workplaces that have only local air conditioning units, dilution ventilation may be done by using exhaust fans and using filters with a minimum efficiency reporting value (MERV) of 13 or higher or High Efficiency Particulate Air (HEPA ) filters applicable to the unit. Proper maintenance of the filters must be ensured by following manufacturer recommendations for these devices.

To achieve the required breathing zone minimum ventilation rates, there must be a sufficient number of exhaust fans based on the room volume. Even with air conditioning, it is advised that windows and doors be frequently opened for added air dilution.

A cleaning and maintenance program for mechanical ventilation systems must be implemented. Workers involved in this process must wear appropriate personal protective equipment.

Proper ventilation in restrooms must not be overlooked. Exhaust fans in these areas must be operational and at full capacity whenever the space is occupied. All users must remember to close the lids of toilet bowls before flushing and to refrain from using hand blowers or jet dryers. The acts of flushing and using hand dryers both contribute to
dispersion of contaminants inside the restroom.

“Riding shuttles can also be an opportunity for exposure to Covid-19 so please do not let your guards down and practice safety and health protocols all the time,” Binag added. Aside from the required wearing of PPEs the following must be implanted inside vehicles: one-seat apart distance, prohibition of eating, drinking, talking and answering calls, and checking passengers for Covid-19 symptoms. This Guidelines also recommend access to open air and opening windows by at least three inches during travel time whenever possible. It also requires regular maintenance of filters of vehicle air conditioning units and regular disinfection of the vehicles before and after each trip.

Checklists for both non-air conditioned and air conditioned workplaces were also provided in the guidelines which can be used by safety officers to assess the quality of ventilation in their workplaces.

END D/Romero