Joey Fox Profile picture
Jun 8, 2022 12 tweets 3 min read Read on X
Reducing COVID risk in a hotel (apartments too) 🧵

The three things you should do are:
1. Verify the building ventilation is working
2. Clean the air in your suite
3. Possibly block the airflow through the door (see below)

1/8
Verify the ventilation is working

The standard way ventilation systems work in hotels and apartment buildings is outdoor air is supplied to the hallway, flows under the door and is exhausted through the washroom. Here's how to check the ventilation:

2/8
1. Use a CO2 monitor. If it's high, you know something is wrong.
2. Go into the hallway and ensure air is being supplied. You can hold the CO2 monitor to the supply air and measure the CO2 being supplied. It should be around 420 ppm (100% outdoor air)

3/8
3. Hold a tissue to the exhaust grille in the washroom and ensure that air is being exhausted.
4. Check to make sure air is flowing under the door.

There might be units in the room for heating and cooling, but they only recirculate air. No ventilation.

4/8
If there are issues with any of this, notify the front desk.

Clean the air in the suite

Open windows and run a HEPA filter. It's best to place it near the door so you are filtering the air that is entering from the hallway.

5/8
Blocking the door

If the windows don't open and the system is working properly, it will be detrimental to block the door. Air is exhausted through the washroom and has to be replenished from somewhere.

6/8
If it doesn't come through the door, it could leak in through the walls of a different suite. So here's the rule:
- If the windows aren't open and the system is working (airflow through the door and up the exhaust) then do not block the door.

7/8
- If you have the windows open or the system isn't working (no air going through the exhaust), then block the door.

If you are blocking the airflow through the door, use painters tape around the door cracks to stop the airflow.

8/8

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More from @joeyfox85

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1/11 Picture of the Tempest PC fan box.
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We just witnessed a new blood libel created over the past day. Unverified claims by Hamas were promoted by MSF, the UN, politicians and many major media outlets.

We've seen the resurrection of all the classical antisemitism: pogroms, massacres, blood libels, death squads
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Nothing has changed. Rav Hanover describes the cruelty in great detail. He mentions the terrible killings which occurred in the towns of Pereyaslaw, Baryszowka, Piratyn, Boryspole, Lubin and Lachowce:   These persons died cruel and bitter deaths. Some were skinned alive and their flesh was thrown to the dogs; some had their hands and limbs chopped off, and their bodies thrown on the highway only to be trampled by wagons and crushed by horses; some had wounds inflicted upon them and were thrown on the street to die a slow death… They slashed the bellies of pregnant women, removed their infants and tossed them in...
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Sep 20, 2023
I've updated my post on Intro to Far-UV.

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itsairborne.com/intro-to-far-u…
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Jul 6, 2023
ASHRAE 241 Equivalent Clean Airflow Rates

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These rates are doubled when there is "vocalization above a conversational level" (e.g. singing)

I'll be hosting a space with the chair of the committee @WBahnfleth to discuss these rates and more. Please join and message for any questions you have.
twitter.com/i/spaces/1gqGv…
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Jul 6, 2023
What should you ask about your indoor air quality?

There are things individuals can do to improve the IAQ in their own space, but it ultimately falls on the building owners and operators to provide clean air. Here are some things you should ask to know about the IAQ.

1/10
1. Outdoor Airflow (OA)
- Is the system constant volume or variable volume?
- If it is constant volume, what is the airflow to the room (in cubic feet per minute [CFM] or liters per second [lps])
- if it's variable volume, what is the max and min airflow?

2/10
- what is the minimum OA % supplied during occupied hours?
- what is the occupancy schedule?
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- how often is it checked and maintained?

Learn about ventilation systems.

3/10itsairborne.com/intro-to-venti…
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"We need HEPA filtration, CO2 at 600 ppm and 100% outdoor air everywhere"

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Furthermore, air handling units can't handle HEPA filters. Demanding this is absurd when it will only increase cost and won't provide any benefit over MERV-13.

Having MERV-13 as the standard is sufficient for particulate matter issues.
Read 11 tweets

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