Question How Many and Which Airflow Test Barriers Are Enough?

[ReveurGAM]

Hi, I'm wondering how many different barriers I should test with. I am testing computer fans to see how well they push through barriers.



At this time, for 120mm fans, I have:

a very fine, metal mesh housed in a 22.5cm, circular, plastic frame;

*a fine, plastic mesh with honeycomb grill (Silverstone SST-FF121);

a fine, rippled, metal mesh (OKGear 12MGAR);

a somewhat coarser metal filter with 1.5mm holes spaced 0.5mm apart (OKGear?);

*a very thin sheet of foam rubber sandwiched between two plastic grills as a frame (Gardtec SC120-P15/45);

a standard fan grill to protect fingers (seems quite pointless to test with as it will not be a wind barrier); and

a finer plastic grill with 1mm holes spaced .25mm apart - it's awkward to use because its 22cm2 and very flexible.



*I also have a super-fine mesh (the holes are so small I cannot measure them, but it's a DEMCiflex square filter 120mm) with magnetic sides that I can't apply because most fans have plastic frames.



I have similar but not identical options as I wasn't able to get some of the above items for 140mm, but perhaps they are out there somewhere. The ones above with an asterisk I don't have for 140mm or larger. The SST-FF121 doesn't seem to be available in other sizes on the Silverstone site.



Should I just stick with the ones I have for 140mm fans, too? That would be 3 barriers, plus the 22cm filter if I can figure out a convenient way to use it on my wind tunnel, which is round. Should I try to find larger versions of some of the unique ones?



Which filters should I use?



Your input is appreciated!

 

[Aeacus]

Which filters should I use?

For dust management? Demciflex.

For keeping out flying debree or poking fingers, any metal grille for your choosing.

I have Demciflex in use with my main PC and with my missus'es PC as well (Skylake and Haswell, full specs with pics in my sig) and thus far, Demciflex filters have kept our PCs almost dust free. Only the very finest dust gets through, since after all Demciflex isn't HEPA.
Btw, Demciflex also offers round filters. And you can even custom order a filter, with your specific needs in dimensions/shape. Oh, while standard Demciflex has magnetic edge, there are those with adhesive edge as well. All that you can customize on their site: https://www.demcifilter.com/how-to-choose-2

So, absolute best regarding dust filtration is HEPA filter. But it would need quite a bit of static pressure from a fan, to pull air through it.
Demciflex is solid 2nd choice and static pressure isn't an issue with this one.

 

[ReveurGAM]

For dust management? Demciflex.

For keeping out flying debree or poking fingers, any metal grille for your choosing.

I have Demciflex in use with my main PC and with my missus'es PC as well (Skylake and Haswell, full specs with pics in my sig) and thus far, Demciflex filters have kept our PCs almost dust free. Only the very finest dust gets through, since after all Demciflex isn't HEPA.
Btw, Demciflex also offers round filters. And you can even custom order a filter, with your specific needs in dimensions/shape. Oh, while standard Demciflex has magnetic edge, there are those with adhesive edge as well. All that you can customize on their site: https://www.demcifilter.com/how-to-choose-2

So, absolute best regarding dust filtration is HEPA filter. But it would need quite a bit of static pressure from a fan, to pull air through it.
Demciflex is solid 2nd choice and static pressure isn't an issue with this one.

It appears I wasn't clear enough; I'm sorry. I'm testing fans, so I wanted opinions on how many of those barriers I should use. I'm also using a U12A as the heatsink barrier, but that's a separate battery of tests.

The DEMCiflex I mentioned is extremely fine, although not even close to HEPA or the step below that. Thanks for the additional info.

If I were ever to go HEPA on my computers, which I absolutely don't see the need for, I would use a Corsi-Rosenthal box filter.

Adhesive won't be ideal because I'm temporarily attaching the various barriers.

Why isn't static pressure an issue with DEMCiflex?

 

[hotaru.hino]

It appears I wasn't clear enough; I'm sorry. I'm testing fans, so I wanted opinions on how many of those barriers I should use. I'm also using a U12A as the heatsink barrier, but that's a separate battery of tests.

You should only use one. While I'm sure adding multiple will increase filtration properties, at that point, you may as well go HEPA.

Why isn't static pressure an issue with DEMCiflex?

Static pressure based fans are geared towards pushing air through a modest obstruction, like heat sinks and basic dust filters.

Although from an intake perspective, I'm not sure if that really matters.

 

[ReveurGAM]

You should only use one. While I'm sure adding multiple will increase filtration properties, at that point, you may as well go HEPA.


Static pressure based fans are geared towards pushing air through a modest obstruction, like heat sinks and basic dust filters.

Although from an intake perspective, I'm not sure if that really matters.

I'm only using one at a time, Hotaru. I use them in separate tests to measure airflow through a barrier. Multiple barriers, although they exist in certain cases, are counter-productive because the airflow drops too much. Even with some of these barriers, the velocity is sometimes so low at the other end of my 2' tunnel that my anemometer doesn't register it.

 

[Aeacus]

Why isn't static pressure an issue with DEMCiflex?

While Demciflex has very fine filter, it isn't thick. Instead, the filter itself is quite thin, thus, there is no need to have high static pressure for air to be pulled through it.

Demciflex also gives a good description about in on their page;

DEMCiflex Air Filters for Computer and other Electronics has only one thin layer of filtering mesh to maximize the airflow to dust caught, ratio. It offers the least resistance to airflow and cause less turbulence than any of the other materials used in computer air filters. This ensures that high air flow and supply is maintained while filtering out the harmful dust and debris.
Air inside a foam filter, for instance, has to pass several elements inside the foam, causing the flow of air to be disrupted more severely causing dramatically inhibited airflow.

What Demciflex filter essentially is:

What a foam filter is:

The more different paths airflow has to take, to pass the filter - the more static pressure is needed to force the air through it.

And of course, with foam filter (or any multi-layer filter), you can't clean those from dust. Instead, when it fills up, you essentially need to buy a new one. Sure, you can use pressured air to blow it clean from dust, somewhat. But depending on air pressure, either you can't clean it fully, or air pressure itself damages the filter (ripping it internally).

I use them in separate tests to measure airflow through a barrier. Multiple barriers, although they exist in certain cases, are counter-productive because the airflow drops too much. Even with some of these barriers, the velocity is sometimes so low at the other end of my 2' tunnel that my anemometer doesn't register it.

What fans are you using? Cheap consumer grade? Or proper, Delta Industrial fans? Noctua could do too.

Speaking of fans and airflow; 11.000 RPM fan:

View: https://www.youtube.com/watch?v=nAFB9w2Rh0Y


😆

 

[ReveurGAM]

I have 200+ fans to test - I lost count as I keep ordering.

The vast majority of them are well-known brands, although some are only known in Europe, others only in other areas of the world. I have a few no-names and some that are sold under multiple brand name (made by one company that sells to many and rebrand it as their own).

Delta, Bgears, Arctic, Antec, SilenX, Xigmatex, XSPC, XPG, Zalman, Corsair, Noctua, Akasa and so many, many others. Some brands I have as many as a dozen models, many I only have 1-2 at this time. There are 2-, 3- and 4-pin fans, Molex D, LED & non-LED, plus fans with proprietary connectors. I think the strongest I have is either a Delta or the EK Furious Meltemi. Probably one of the Deltas.

Thanks for the explanation about DEMCiflex. Now I understand!

Would I be best off ordering larger DEMCiflex filters directly from them, or off other sites in order to save money. I'm not an engineer or someone else with a large salary, and I have no donors or sponsors.

Oh, my target audience is consumers, not businesses. I might someday decide to add server-grade fans, but not at this time.

 

[Aeacus]

Would I be best off ordering larger DEMCiflex filters directly from them, or off other sites in order to save money.

This is up to you. You may not find larger (e.g 200+ mm) filters from normal retail/online shops, whereby making order from their site is only option.

For my builds, i bought the complete set made specifically for the PC cases i have in use and i was lucky that my #1 online store did had the specific filter kits in stock.

I have 200+ fans to test

Now i'm curios. Why?

Oh, my target audience is consumers, not businesses. I might someday decide to add server-grade fans, but not at this time.

So, you're similar to GamersNexus, JayzTwoCents, Igor'sLab, but only focusing on PC case fans?

 

[ReveurGAM]

Now i'm curios. Why?

Because of the limitations I face in my testing, each fan tested helps to provide data to rank fans and infer what I can't measure. My target audience is consumers, who often know nothing about choosing fans.

So, you're similar to GamersNexus, JayzTwoCents, Igor'sLab, but only focusing on PC case fans?

I can only hope to be that well- regarded someday. At this time, yes, but eventually I also want to test thermal compound and pads, as well as coolers.

Thanks for your help!

 

[ReveurGAM]

While Demciflex has very fine filter, it isn't thick. Instead, the filter itself is quite thin, thus, there is no need to have high static pressure for air to be pulled through it.

Demciflex also gives a good description about in on their page;

What Demciflex filter essentially is:

What a foam filter is:

The more different paths airflow has to take, to pass the filter - the more static pressure is needed to force the air through it.

And of course, with foam filter (or any multi-layer filter), you can't clean those from dust. Instead, when it fills up, you essentially need to buy a new one. Sure, you can use pressured air to blow it clean from dust, somewhat. But depending on air pressure, either you can't clean it fully, or air pressure itself damages the filter (ripping it internally).


What fans are you using? Cheap consumer grade? Or proper, Delta Industrial fans? Noctua could do too.

Speaking of fans and airflow; 11.000 RPM fan:

View: https://www.youtube.com/watch?v=nAFB9w2Rh0Y


😆

I wonder if I have that Delta....?

 

[Aeacus]

I wonder if I have that Delta....?

Small, but very powerful.

Delta Industrial makes all kinds of fans, from the small but mighty, to all the way up to the King of PC fans;

View: https://www.youtube.com/watch?v=blU_2wIMT4U


And if that Delta big boy isn't enough, then look towards God of fans;

View: https://www.youtube.com/watch?v=QwIlhuR_N2g