The Math of Social Distancing Is a Lesson in Geometry | Hacker News Reader

The Math of Social Distancing Is a Lesson in Geometry

quantamagazine.org

47 pointstheafh25 comments

This is a pretty bad premise. If you're packing people in cubicles in a building/floor that most likely uses central air and air conditioning, you already lost the game -- sphere packing or not.

+1 came here to say this.

Indoor HVAC air flows seem way more important than distance. I can probably sit right next to you as long as the airflow has each of our exhalations taken away from the other.

My employer has mentioned potential plans to bring people back to the office in small numbers for short times. Until these discussions include analysis of building HVAC, I want no part of it.

We all need downdraft hoods. Eating out with friends will be like going to hibachi, but instead of a grill between your friends, it will be a downdraft vent pulling all of your exhalations away.

I had the same thought. The math is interesting, but I hate the premise.

Packing spheres might help prevent some transmission, but based on other reports, HVAC flow is a contributor. You can have everybody sitting 10' apart, but if the air moves consistently in one direction, anybody stuck downwind of a typhoid mary runs a high risk of infection.

To a point yeah, but total ventilation rates in the form of room air-exchanges per hour probably matters more.

This. HVAC systems basically neutralize all these efforts in office buildings.

+1 People are not mathematical spheres.

Reminded me of the old joke: "here's the solution, but it only works for spherical cows in a vacuum".

I think the most efficient solution would be to have a series of snorkel lines come down from the ceiling that terminate outside of the building, 6 feet apart.

This would allow the occupants inside to pack as closely as possible without worrying about breathing any hazardous air.

Or for an actually efficient solution, just oversize the shit out of the HVAC. Can it still spread via droplet in a wind-tunnel? Sure, but not very well.

Pasteurization occurs at roughly 145 degrees Fahrenheit, so another solution could be to increase the ambient temperature of the office to 145F or higher, and to simply have all of your workers wear personal temperature controlled suits to keep them at their preferred comfort level.

Jokes aside, couldn high intensity UV lamps be placed inside the HVAC tubes and have that sterilize the shirt out of the air?

That's not really the issue although it does matter for some aerosols sizes. It's the flow rate in the room. You need more air exchanges. When someone coughs, how long are those infectious particles floating around the room.

Good point. As for coughing/talking/anything that makes droplets I was thinking masks first and then other measures on top of it, like proper ventilation.

...or in the case of most offices which require cublicles -- WFH and be done.

Sphere packing is a genuinely interesting math problem. But it really should not be thought of as any kind of solution to a serious public health threat. Six feet apart is only a recommendation. The virus can transfer based on many other factors such as airflow, shared surface contamination, and spending time in proximity to asymptomatic carriers.

Leave such math topics for home school study questions.

The rule is supposed to encourage being apart from each other, not how many can you pack into an arbitrary measurement from Some Agency.

In the UK it's 2m which is MORE than 6ft.

For this purpose, 6 feet and 2 meters are the same measure.

It's "about this far apart" and the UK isn't going to advise their population to "stay at least 185cm apart" anymore than the US is going to advise "stay at least 6'6" apart".

How about maximising the minimum distance?

Not breathing the same air and not sneezing / coughing / speech spitting on others is what the 6 feet, 2 meters numbers are about.

As usual the best solution is one that avoids the problem. If working remotely is an option, if not even being at risk is an option, just don't place the bet and keep holding that curve down.

If anyone is still thinking in terms of "like returning to normal", at least before there's a wide-spread and effective vaccine, they're already starting from the wrong foundation of thought.

The next release of our PerfectTablePlan seating software (https://www.perfecttableplan.com) will have a social distancing feature. This will allow you to check social distancing at seated events (such as wedding receiptions and galas). It wasn't too difficult to add as we know the x,y position of each seat and the group each occupant belongs to.

I worry that a feature like that could give people a false sense of security. In an indoor area, transmission is possible regardless of distance.

The 6’ rule was intended for the outdoors and situations where contact is unavoidable, not parties.

Spacing guidelines are always going to be imperfect. But, assuming they are based on some science, they are better than nothing. You can also record all the guest details in PerfectTablePlan for later track and trace!

So it’s more on the lines of imperfect table plans. My worry is circulating air flow.

I don't think we'll be adding a CFD model. ;0)

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