Thread by @IntegrityIGP

[Thread] With COVID-19 running rampant in the US families are having to deal with someone testing positive who has no place to stay but at home with others. This thread will teach you how to isolate part of a house and create a negative pressure zone to limit spread.

[2] This thread is free for anyone to reproduce. The important thing is to save lives. Feel free to share it far and wide in any medium you like. There is a 25 tweets at a time limit so this is in 2 parts.

[3] The science in this thread is the same used every day in industrial and medical locations. It is the same principals that allow you to eat in a nice restaurant without being smothered by smoke from the kitchen, or smelling the bathroom. Ask any questions you have.

[4] In air (or other gasses and liquids) molecules and particles actually diffuse very slowly. If you drop a little food coloring into a glass of water you can watch it take minutes to diffuse throughout the glass.

[5] The same is true for the air in a house. Any virus or micro-droplets containing virus in the air will diffuse very slowly, but can be moved quickly by air currents. So we will control the air currents to protect part of the house.

[6] The part of the house without virus, which is safe for those not infected, will be referred to as "house" and the area where anyone testing positive is allowed will be referred to as "room."

[7] As you read this thread and plan out a space remember this rule. The goal is to always have air flowing from the "house" to the "room," and never to have air flow the other direction. You will not seal them from each other, that would be impossible.

[8] Time to pick a space. When deciding what area to select as your "room" there are 3 things to pay attention to.

1) A bathroom. COVID negative people can not safely share a bathroom with someone COVID positive.

2) The "room" will need a window or similar to vent ...

[9] ...Air to the outside. Make sure the air doesn't get back into the house (or another) after it is vented.

3) HVAC (central AC / heat) air returns. If you have an area without one that is best, but if you can't avoid it you will have to block it off. If you do...

[10]...have to block off an HVAC return make sure the system has adequate returns in another area of the house.

Here is a simple 4-2 floorplan. A master suite or other room with an on-suite bath is a good choice.

[11] Now that you have the area selected to be your "room," you need to turn the drywall layer into an air restriction envelop. You can do this pretty easily with a roll of masking/painters tape and some plastic. Trash bags will work.

[12] Remember you don't have to create an airtight layer, just a restriction so we can control the airflow. The trick to this is to make sure any holes are small, you don't have to seal everything perfectly. Just think how you can blow out candles...

[13] if you pucker your lips, but you can't control the air enough if you open your mouth as big as you can. Also imagine sipping your drink through a paper towel roll. So small holes. Just tape over anything bigger than a pen.

[14] For the vents in the bathroom make sure you turn them off and tape the switch in the off position so you don't accidentally turn it on later. Put plastic over the vent and tape around the edge.

[15] Any place where the AC blows out, go ahead and close them also. You are going to be venting through the door so you don't need the cooling/heating in this room anyway.

[16] The one exception is if you were unable to find a "room" without an air return for the HVAC. If this is the case you need to 100% seal that duct. Call a friend if you have to. That needs to be completely sealed. Ill give some tips later.

[17] At this point you should have your "room" ready with the drywall as an air restriction envelop except for the door, and the window. We need to turn the window into an exhaust from the room.

[18] The easiest way to do this is to put a fan blowing out the window, and seal around the fan. A scroll fan will be more forgiving but even a $20 box fan will work. Just make sure it blows out and you seal from the fan to the window frame.

[19] This is a good time to test your setup. Turn the fan on, and turn the AC off in the house for now. Have someone inside the room and someone on the house side of the door. Crack the door just a bit and you should feel air blowing through the crack.

[20] a good way to double check this is to light some incense on the "room" side of the door. Even with the door cracked the person on the "house" side of the door shouldn't be able to smell the incense... not even a little. You should be able to...

[21] follow the smoke from the incense by the door all the way to, and out, the window. None of it should blow back into the house. At this point you are almost done. Just a few more steps.

[22] Now have the person on the "house" side of the door go to the other side of the house and crack a window. You are pulling air out of the house, into the room, so you need a way for new air to get in. If your HVAC has a fresh air vent set that open also.

[23] After cracking a window the person on the "house" side can turn on the HVAC. Even with the HVAC on and the door into the "room" cracked, the person on the "house" side should not be able to smell the incense.

[24] Now go to the front door of the "house" and open and close the door several times quickly. If you still don't pull any incense into the house your negative pressure room is working. Just a few notes and tips to go over.

[25] Remember you are controlling the air flow, doors are basically air pumps. If you slam doors it is harder to control the air, so all doors, even those nowhere near the "room" need to be opened and closed SLOWLY.

[26] To help you in case you forget and open the door quickly you can add another layer of defense. Hand heavy cloth like denim or canvas over the door into the "room" attached at the top and weighted at the bottom.

[27] Now remember everything and everyone that comes out of the "room" is contaminated. You need to be extremely careful with it. Placing it directly into a plastic tray and spraying with peroxide is a good idea. Use gloves, wash hands, wear a mask whenever you have to touch it.

[28] I'll add if anything comes up from questions. Hopefully this will help some people be safe and save lives. This isn't perfect like a billion dollar biocontainment room but it should greatly decrease risk.