Comment by thaumasiotes
3 years ago
> This article actually makes a bunch of claims itself that are false.
There's this howler:
> This passage implies that a (“true”?) HEPA filter is designed to capture particles that are 0.3 microns or larger. But an H13 filter must, by definition, capture 99.95% of particles of all sizes.
According to this guy, an H13 filter is required to capture 99.95% of neutrinos that pass through it. He's not in a position to accuse anyone of not knowing what they're talking about.
Moving to wikipedia, we see this text:
> Common standards require that a HEPA air filter must remove—from the air that passes through—at least 99.95% (ISO, European Standard) or 99.97% (ASME, U.S. DOE) of particles whose diameter is equal to 0.3 μm
I know which of those claims is more plausible. The standard described by wikipedia is theoretically capable of both being measured and being met. Neither is true of what dynomight.net says.
You cannot possibly be serious.
If you are, well, you will find that particles are contextually defined as pieces of matter in the solid or liquid phase which are suspended in the air.
I don't know if the standards body took pains to define matter in terms of atoms but if you want to run off and check? I won't stop you.
He's just honing his HN pedantry to a razor edge so he can point out that ackshewally it's not an air filter at all because it isn't restricted to gaseous fluids in the ratio of 0.78 oxygen to 0.21 nitrogen plus trace gases.
It can actually filter many types of gaseous compositions so it's really a gas filter. Have the authors even done a rudimentary PhD on filtration nomenclature? They are clearly unqualified to comment.
Seriously though I've seen enough of these sorts of Poe's that at least some of them must be serious. Must be weird living your life like that.
> you will find that particles are contextually defined as pieces of matter in the solid or liquid phase which are suspended in the air.
What is this supposed to mean? The solid or liquid phase is defined by the interaction of related molecules with each other. Suppose I have a cluster of 15 water molecules, suspended in the air, interacting with each other such that I can call them a tiny droplet of liquid water. Suppose I have one oil molecule, also suspended in the air. It is much larger than the 15 water molecules are combined. But it's not in a solid or liquid phase, because there's only one of it. The filter is required to handle the water, but there are no requirements for how it should handle the oil?
> What is this supposed to mean?
What it means is that you're trading on a half-recalled education, and trying to sound clever, but what's happening is you're being annoying in various not-even-wrong ways.
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