The following information provides an overview of ventilation in the context of an Australian Optometry Practice during the COVID-19 pandemic. Optometry Australia recommends that Australian optometrists review the following information carefully.
The key takeaway is following good hand hygiene as much as possible, triaging patients before they enter the practice, and open windows were practical to improve airflow. To support members, Optometry Australia has provided further information on both infection control and triaging patients for urgent and critical care.
Advice provided around the world
The Centers for Disease Control and Prevention (CDC) in the United States recommends isolating symptomatic patients as soon as possible. Set up separate, well-ventilated triage areas, place patients with suspected or confirmed COVID-19 in private rooms with door closed and private bathroom (as possible), prioritize AIIRs for patients undergoing aerosol-generating procedures.
Some studies, such as the one by Jingyuan Wang, Ke Tang, Kai Feng and Weifeng L “High Temperature and High Humidity Reduce the Transmission of COVID-19” have been suggesting that higher temperatures and higher humidity may reduce the community spread of COVID-19, however implementing this in outpatient clinics as a measure of control is unsubstantiated, impractical, and has not been recommended by the World Health Organisation (WHO), CDC, Australian Department of Health or any other relevant authorities.
The Australian Department of Health Coronavirus Disease (COVID-19) Social distancing guidelines suggest “Consider opening windows and adjusting air conditioning for more ventilation”. Obviously in most optometry outpatient settings there is limited control over ventilation, and ventilation standards are not the same as controlled hospital settings.
The Federation of European Heating, Ventilation and Air Conditioning Associations has released some guidelines on what they believe is increased safety precautions to reduce transmission, both in and out of a hospital setting. In a paper titled “REHVA COVID-19 guidance document: How to operate and use building services in order to prevent the spread of the coronavirus disease (COVID-19) virus (SARS-CoV-2) in workplaces” they suggest:
In buildings with mechanical ventilation systems
- Start ventilation sooner than opening hours, and continue beyond closing
- Ideally; continue ventilation systems for 24/7, which may reduce airborne viral load
- Supply as much outside air as possible
- Ventilation in toilet areas should be on 24/7, to reduce fecal/oral route transmission
Use more window airing
- Have as many windows open as possible, even if this causes some thermal discomfort
- Open windows in toilets with passive stack/mechanical exhaust systems may cause contaminated airflow from toilets to other rooms. Open windows in toilets with mechanical exhaust systems should then be avoided.
Humidification and air-conditioning have limited effect
- Preliminary data suggests that in order to have any significant effect on COVID-19, temperatures would have to be in excess of 30 degrees and humidity above 80% therefore;
- Heating and cooling systems can be operated on the basis of thermal comfort, and do not effect viral spread
Safe use of heat recovery sections
- Ensure that there is no transmission of “dirty” exhaust air contaminating the inward bound air supply through system leaks, as this can cause viral particles that have been ventilated out to re-enter the system
Do not use re-circulation systems
- This is the case even if there are filtering systems, or if thermal discomfort occurs
Duct cleaning has no practical effect
Room air cleaners can be used in specific circumstances
- Need to have at least HEPA filter efficiency to be effective
Flush toilets with lid closed
Support for our members
We realise this is a difficult and uncertain time for all of us. Optometry Australia’s optometry advisor helpdesk offers our members dedicated experienced optometrists ready to provide confidential support. Please ensure you have your member number ready when you call.