Thread by @marwa_zaatari

🧵The search for ventilation.
Hotel & COVID-19 Edition.

I stayed yesterday at brand name hotel. Here are some observations about shared air, outdoor air, and maintenance issues.

The room I stayed in does not have shared air. This is typical for hotel rooms. Air in your room gets recirculated and conditioned within your room only - by design.

Pic for unit in my room: window unit with fan and cooling/heating coil.

Indoor air gets recirculated on the side, conditioned and then blown from the top - as shown by my infrared camera. Blue = cold air. orange = "hot" air.
Hint: to know the intake of air on the unit, look where there is dust.

This unit only provides recirculated indoor air - NO outdoor air. I double checked with the brand name manufacturer.

Ok. Where is outdoor air coming from?
Typically, you will see a supply air in the corridor like the picture here.

In the hotel I stayed in, no outdoor air unit is found on the hotel premises and no sign of any supply of outdoor air in the room.

Other method to get outside air is to supply it to the corridor and then get outside air from the door to the room. However, the door is this room was sealed shut and I verified (three different methods) there was no air coming from the corridor.

The only other way is outside air brought in from the windows. However, I could not open them as there were sealed shut. I called the operator and asked her "how do I open these lovely windows", she said she worked at the hotel for a long time and never got asked this question.

In the bathroom, there was exhaust fan (fan taking air from bathroom and room and exhausting to the outside) continuously.

(it does not look pretty as it is never cleaned).

Because of the exhaust fan, taking air from room to outside, room pressure is <0. Meaning that air is being sucked in from corridor or adjacent room. For this room, there was air (small quantity) coming from an ill-sealed door from adjacent room.
My go-to-solution is duct tape.

(unrelated to this thread, if you ever watched forensic files, you would know to always check that this door between two rooms to be always closed)...

I noticed that the air conditioning system in my room has back mold. Unfortunately this is typical as the model is "design and forget".
I took bio-sampling and will be sending the sample to a lab to get the results of what I was breathing. (will share the results).

I also took CO2 data and particulate matter samples from 0.3 um to 10 um in size (will share the results when i graph the data and compare to other environment).