The Ministry of Health, Labor and Welfare has recently issued a guidance document entitled “New measures to control infectious diseases from coronavirus”, which contains recommendations on potential cases. out cross-contamination of diseases in everyday life. These are “enclosed spaces with poor ventilation”, “crowded places” and “close distance conversations”.
It also encourages residents to ventilate their residence, such as “in a windowed environment, open these windows in two directions at the same time, if possible, to conduct ventilation.” However, there is no specific information on how much ventilation is sufficient and how to do it accordingly. Because depending on the specific environment, the situations that arise will require different ventilation measures.
To solve this problem, the Japanese Institute of Architecture and the Association of Air Conditioning Engineers came forward to share how people should perform the “ventilation” as follows.
1. The ventilation speed is 2 times / hour
This concept is often misunderstood as “opening the window twice an hour”. But not true. Ventilation rate is an indicator that shows the rate of air exchange, in terms of the number of times that the internal air volume is replaced every hour. It is determined by the size of the entrance and exit when air is exchanged, as well as the size of the room itself.
As the number of ventilation increases, the old indoor air can be diluted with new outside air and gradually replaced faster.
2. Natural ventilation and mechanical ventilation
Ventilation can be divided into “natural ventilation” in which the windows are open and “mechanical ventilation” means the use of fans. In buildings and vehicles like cars with windows, the most effective way is to open the window proactively to get outside air in. Cars should also set the mode to take outside air instead of “mode air circulation inside”. However, in cars, it is important to check that the intake and exhaust ports are not blocked.
3. Ventilation in rooms without windows
In buildings or offices, air conditioners are often used to provide air. However, for ventilation, it is necessary to maintain new airflow from the outside, although they will reduce the cooling or heating efficiency of the air conditioner. At this time, mechanical ventilation may be required.
A household air conditioner usually only helps to circulate air and does not support ventilation. Users should open windows or operate ventilation systems in air-conditioned rooms only.
4. Air purifier
Air purifiers generally do not have a significant effect on ventilation, because the amount of air passing through the machine is much smaller than the volume of air needed to circulate to ensure ventilation speed. Due to the poor performance and scope of the air purifier, users should use common ventilation such as opening windows and using fans, instead of relying solely on air purifiers.