by JackPollard
December 10, 2020
Part 1: Low Tech & High Tech
You’ve heard the advice: limit your contacts, keep your distance, stay at home. That’s great, but how do you stay safe when you live in a house with ten other people?
For nearly a year everyone in the US has made decisions about how to stay safe, about how to stay safe during the pandemic and still have a life. It’s stressful and not easy to know whether you’re doing too much or too little. Now, add in the fatigue that comes with it all. Everyone is stressed.
In the Star Community, where sixteen community members live together in two large houses, the decisions have been even more complicated. One of our Star Community members is an RN, in regular contact with seriously ill patients. We have a three-year-old that we wanted to keep in pre-school. We have several community members who fall into high risk groups of one sort of another.
Add in another big wrinkle: Star Community has a lot of polyamorous people, and there are several important relationships with people outside of our two-house bubble.
So how has Star Community responded? Here’s our story. In this article I talk about the technological solutions that have worked for us. In a later article, I'll talk about all of the social and behavioral approaches we’ve taken. Not as easy and clear cut as the technological solutions, but equally important.
Just to say up front, no one in Star Community has contracted COVID yet, knock on wood. So far, so good.
Approach #1: Fresh air!
It’s pretty clear by now that very few COVID infections start outdoors. The reason is simple—when there’s a lot of air movement it’s hard to inhale a lot of virus from others.
Imagine sitting with someone who’s smoking. If your outside with even a little breeze it’s pretty easy to avoid the exhaled smoke. Put yourself in a small enclosed room with no air movement, you’re going to be breathing cigarette smoke, like it or not.
Opening the windows is pretty low tech, but it works! It was a blessing that the first two waves of the pandemic were in the spring and summer. The simple solution for Star Community was to keep lots of windows open. And if you need to, speed up the air movement with box fans. Keep the air moving.
But what works in Summer in Seattle won’t work in December. So what to do next?
Approach #2: HEPA Filters
HEPA stands for high efficiency particular air. HEPA filters can filter out particles as small as COVID virus particles. Viral particles are pretty small. I don’t know how that can work, but the experts say they can. So we use HEPA filters by taping a filter onto the back of a 19 inch box fan, and just blow the house air through the filter. The one downside here is that box fans in a living space can be noisy.
Besides the virus, you’ll be surprised how much dirt in the air gets trapped by the filter! (By the way, we improved the filters in the forced air furnace. HEPA filters are tricky in a furnace because they cause the furnace to work harder to force the air through. It can be done, but contact a professional if you want to do this.) So, this approach is easy, fast, and doesn’t cost that much. Open the doors and windows, filter the air, and you’ve got a lot of protection. But it’s winter, and we wanted more.
Approach #3: Ultraviolet - C
Using specialty bulbs that produce ultraviolent – C wavelengths (everyone calls it UVC) is a good, practical, but more expensive approach to mitigating COVID exposure. UVC bulbs produce light centered around a frequency of 254 nanometers (written as 254um). But it is more expensive, and there are some health dangers associated with improper UVC installations.
First, some basics. UVA and UVB are the wavelengths of UV light that give us sunburns and snow blindness. UVA and UVB naturally come from the sun, and we can get an uncomfortable sunburn if we’re not careful.
UVC is a little different. It also comes from the sun, but our atmosphere completely blocks it. UVC never reaches the earth’s surface.
Special bulbs can generate UVC light. It turns out the UVC is very good at killing bacteria, viruses, and molds. UVC has been used for decades by water treatment plants, hospitals, in HVAC systems, and any other space where a sterile environment is desirable. UVC works by disrupting the DNA or RNA of virus particles and cells, quickly and efficiently.
Is this risky for humans? UVC is bad for your eyes. Nasty. You can’t look directly at a UVC light source, even briefly. But with the right precautions you can bring UVC protection safely into your living space. You can’t get sunburn like symptoms because the UVC doesn’t penetrate beyond the dead cells that make up the outer layer of your skin.
Star Community did the research. You can check this out for yourself, here, here, here, here, here, and here. In September—before we had to close the windows—both Star Community houses built and installed UVC systems using two separate strategies.
The first UVC strategy was to buy a UVC light manufactured by Honeywell that installs into the return duct of a forced air furnace. (If you don’t have a forced air system, keep reading, there is a second strategy).
The UVC system turns on when it senses the air flow through the duct. Assuming that the heating/AC system circulates the air in your house two to three times an hour, the UVC light will kill roughly 95-99% of the COVID virus that’s passing through the furnace. Pretty good!
We bought the UVC system from Honeywell, and we installed it ourselves. Easy enough. A little expensive (up to $500). But when you’re sharing the costs across a bunch of people, not so bad.
BTW, one of the nice things about living in a group home is that there is often somebody who can do a particular maintenance/mechanical task. That’s true for Star Community at least.
There is a limitation to this strategy though. What happens if someone in the house is asymptomatic but shedding virus, and you were sitting across the table from them? The general circulation of the air through the furnace UVC system might not be sufficient in this situation.
Our second strategy was to build several UVC light boxes and keep them in the common living spaces. The light boxes gave extra protection by killing off any virus floating around the common areas. For this to work, the virus has to be within two to three feet of the direct line of sight from the UVC bulb. The air in the living space has to be moving, so that the bulb can be exposed to as much air as possible. At the same time, the light box has to be high enough thatthere has to be no chance that someone will see the UVC light directly.
I said earlier that UVC is not visible to the human eye. What you see in the picture is a turquoise colored light in the visible spectrum. About 5% of the bulb’s energy goes to producing this frequency of visible light. This is really a feature, not a bug. It’s good to know when the lights are operating just for safety sake.
The solution was to put the light boxes on top of kitchen cabinets and bookshelves. In the picture, the box is on top of a tall bookcase. We made these ourselves; what was available commercially was expensive. It turned out that building them was easy.
The picture to the right shows the bulb we used in the light box. It’s called a COOSPIDER CTUV-36 ($42.79). There’s a lot of bulbs coming out of China right now. Don’t go for the cheapest one possible. Also, don’t buy a bulb produces ozone. UVC bulbs are designed to either produce or not produce ozone. You don’t want to be breathing ozone in your common areas! Also, mercury is used in these bulbs.
You can order the bulb from Amazon.
Here’s what it looks like inside of the UVC light box. We lined the box with aluminum foil. We also wrapped the electrical cord coming into the box with foil to protect the plastic from long term intense UVC exposure. Aluminum is one of the few materials that reflects UVC. Lining the box maximized the bulbs effectiveness. Very little, if any, UVC reflects off of other surfaces like living room ceiling or walls. It’s hard to see in this picture, but we suspended the bulb a couple of inches above the bottom to hopefully keep it cooler and prolong its life. We used picture hanging wire to do that trick.
If you’re going to build your own UVC light box system, two additional items are useful. First, buy a meter that measures the amount of UVC light in the environment. Use the meter to make sure that you have no leaks or mistakes in the light box, and that their height is sufficient. Second, buy safety glasses that block out UVC frequencies. We built the boxes and carefully tested them without actually looking directly at a bulb, but it was nice to have the safety glasses in case there was a mistake.