If you're lucky enough to have central air in your house, you probably have only one unit for the whole thing. The ductwork going from that unit will have a branch going to every room. Somewhere in the basement, or attic, or in some cut away part between floors, every branch will have a damper so you can balance the air to prevent your bedroom from being an inferno and the room closest to the "trunk" from being a meat locker. And you know full well the jump in your power bill after that first summer month when you kick on the AC.
The same is true in winter, of course, when you kick on the furnace to a toasty 70 degrees. The family is wearing t-shirts and looking out the picture window at snow blowing past completely sideways.
Human bodies are pretty forgiving. If the AC broke or the heat went out, we could cope for quite awhile. Or you could always crash at someone else's house, who wasn't too cheap to buy that new furnace last summer… Well, vaccines aren't forgiving.
Before I can get into the extreme realm of HVAC at a vaccine plant, I first must describe a typical building layout better than I have previously. Let's revisit Menengvax and the company that makes it, WMC. Their new plant will make vaccines that sell in the United States, Europe, Australia, some parts of South America and in most of Asia (if you wonder why not Africa, it is because WMC doesn't sell to Africa, but donates a million doses a year to various NGOs for distribution, but you don't ever hear that in the news). Because this product will sell in all these areas, WMC's plant must align with the regulations of all these different areas (the FDA in the US, the EMEA, IMB, MHRA and others in Europe, the TGA in Australia, etc.). What are the basics for all these different regulated markets? We'll boil them down here:
1) Space: lots of it. Cramped working quarters leads to having product and waste in the same area, to lots of people in one room, and to the potential for accidents, all of which leads to low product quality.
2) Organization: one start and one finish. If product moves as if on an assembly line, you're not going to get a car with two engines and no tires, so to speak. This is like saying your dining room is for dining and the kids better damn not do homework on that table!
3) Engineering: don't tell personnel to do something (a procedure), don't give them a choice (engineer the work). Vaccines are temperamental. The greenest person on the floor has a few hundred thousand dollars worth of training behind them. If you have them focus on a real problem, like how to make a few thousand cells that live in a test tube, grow into a few gazillion cells in a 5000L fermentation tank, they'll get it right every time. They shouldn't be tripped up by something like walking through the door on the left instead of the door on the right. "Enabling success" in the brains on the floor means dedicating money, other people, and real estate to the job.
4) Document: if it isn't written down, it didn't happen. That's pretty clear, in and of itself.
So to facilitate these things, WMC has built a facility that, in the very center, has less that 100 particles bigger than 5 micrometers (there's a million micrometers in one meter) in diameter. If you figure that at least once a summer, you inhale a full sized fly while mowing the grass, you can see how keeping air this pure all of the time is a bit difficult. All air starts like that around us all the time: full of pollen, bugs, dirt, bacteria, moisture, and everything else in the world.
There are two ways for air to get into a room: the doors and the ducts (assume the rest of the room is as tight as a drum, which is true in the Land of Pharma, but hardly anywhere else, save a submarine). The ducts can have filters on them. So could the doors, but it'd be hard to get a person through a filter in one piece. Instead, a room with air ALMOST as clean is adjacent to that most clean central room. Then another almost as clean as that one is next. And on it goes until WMC can be sure that the air in the room where they make Menenvax is as clean as it needs to be to make good product and thereby ensuring that all regulators will be happy with the process.
Enough for now. We need to get back to the matter at hand: how do we get "Fresh Air," full of all that pollen and spit, to be so clean?