A lot of talk this week has been about a study that points to fecal matter, which can carry SARS-COV2, being aerosolized when flushing a toilet. This would intern create additional airborne particles that could infect an occupant. Among the recommendations are: putting the toilet lid down before flushing, clean the toilet seat before using it, since floating virus particles could have settled on its surface, and washing hands carefully after flushing, since virus particles may be present on the flush button and door handle.
It is well documented that fecal matter can be ejected from a flushing toilet, and that closing a lid helps reduce that issue. In fact, there are multiple “Mythbusters” episodes on just that topic. However, the question of the week is “Is it reasonable to install lids on public toilets?”
As we aren’t infectious disease experts, we can certainly make some observations on the subject:
- Fecal matter is common in our environments.
- Installing a lid creates another touch point.
- Where automatic flush valves are installed, the lid likely blocks the sensor until put down.
- What if the previous person was infected, and didn’t lower the lid? Now the next person is potentially exposed.
- The particulate size in the study may take between 8.2 minutes and an hour to settle. How do we address that?
- How much infected material is transmitted from the fecal matter, to the toilet water, and subsequently expelled into the air?
Whether or not you decide that toilet seats are right for your facility, the common industry guidelines on restroom ventilation, reduction of touch points such as flush valves, faucets and door handles should be continued. Disabling electric hand dryers and providing paper products can reduce turbulent air in a restroom, and good hygiene is a must. I think it’s also reasonable to point out that we rarely make decisions based on one piece of information, and while this study does point out some potentially viable transmission modes, we should look to more than one dataset prior to making policy decisions.
Contributor: Stephen Osken, PE, LEED AP, Director of Mechanical Engineering at Barton Associates.
