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Discussion Starter #1
So you have a very tiny case; crammed in there are alot of parts, there is no filter, just the fan to the case, is it better for a high static pressure fan or a high air flow fan. I would guess high airflow, since the air is only pulling in air. however I am not entirely sure.
 

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The answer is both. You need both, and actual flow in a given circumstance is measured by P-Q, not by someone slapping "SP" or "AF" in the fan's name.

Give a little more info about your scenario and build, and some people should be able to get you some suggestions based on fact.....you will just need to weed through the "oh you need SP fans because (enter completely unrelated circumstance here)".

This has become the topic with the greatest amount of misinformation in forums these days.
 

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Quote:
Originally Posted by SaintsEnd View Post

So you have a very tiny case; crammed in there are alot of parts, there is no filter, just the fan to the case, is it better for a high static pressure fan or a high air flow fan. I would guess high airflow, since the air is only pulling in air. however I am not entirely sure.
ideally, if you only have 1 fan in the case, you want it to be a filtered intake fan. as ciarlatano has already mentioned, it would help alot if you can describe the build alittle more so we can help you to achieve your goal. generally speaking, PSU has an exhaust fan on it so if you use the only fan mount you have for intake you will still have the PSU as exhaust fan. if you have a video card in the build, the GPU fan is also generally regarded as an exhaust port as well. so if you have a chassis fan mount, it would be best to put a high static pressure fan on it so you can use it as a filtered intake. unless we know more about what you are trying to build, it's really the only educated guess we can help you with.
 

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Discussion Starter #6
Ill make it really simple. There are two intake, two exhaust. It can be positive, negative or neutral pressure.

There is a straight path from the two intake to the two exhaust however there is an object in the way preventing this straight airflow (be it wires, graphics card, motherboard, you can use your imagination)

There also is a dust filter behind the intake fans making it more difficult to bring in air so you can assume they are high static pressure.

The only thing that will touch or get directly in the way of the exhaust fan are some fan grills or something to help prevent contact with the fan blades.

Will there be any benefit of using a high static pressure fan to exhaust vs a high airflow fan?
 

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something tells me the object in question is not a computer.

given that assumption, i would say try to balance the intake CFM with your exhaust CFM. meaning if you are using some HIGH pressure fans(3000+RPM fans) on the intake side, you want to take a percentage off their rated CFM to account for the filter resistance as well as the internal component obstruction. another way of adjusting to this is to have 2 intake and 1 exhaust so the actual airflow is balanced. just make sure the exhaust fan is mounted near the hot component so the hot air is forced out of the enclosure as quickly as possible after the cooling air has done its job.

without more specifics as to the object you are working with and the sizes of the fans we are talking about, this is the most amount of help i can provide. if we have more information as to what we are working with, then we may be able to offer better assistance and maybe even change the configuration of the cooling (4 intake and let passive leakage be the exhaust if the enclosure has sufficient leakage points at the right locations.
 

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Quote:
Originally Posted by SaintsEnd View Post

So you have a very tiny case; crammed in there are alot of parts, there is no filter, just the fan to the case, is it better for a high static pressure fan or a high air flow fan. I would guess high airflow, since the air is only pulling in air. however I am not entirely sure.
Quote:
Originally Posted by SaintsEnd View Post

Ill make it really simple. There are two intake, two exhaust. It can be positive, negative or neutral pressure.

There is a straight path from the two intake to the two exhaust however there is an object in the way preventing this straight airflow (be it wires, graphics card, motherboard, you can use your imagination)

There also is a dust filter behind the intake fans making it more difficult to bring in air so you can assume they are high static pressure.

The only thing that will touch or get directly in the way of the exhaust fan are some fan grills or something to help prevent contact with the fan blades.

Will there be any benefit of using a high static pressure fan to exhaust vs a high airflow fan?
Quote:
Originally Posted by Jidonsu View Post

Given the lack of specific details, I can only assume that the OP is actually building a tiny chamber meant to enslave little children.

Next thing we're gonna get asked is how he should run the feeding...I meant water cooling....tubes.
I agree with Jidonsu
thumb.gif


OP is not giving us the info needed to configure system.

@SaintsEnd, we cannot give you specific answers to your extremely general and broad questions. Airflow is not a simple thing. Everything involved in system effects the path and rate the air flows. Even knowing all the assumed variables does not mean we can accurately predict what will work. It's like trying to predict the weather.
 

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Quote:
Originally Posted by doyll View Post

I agree with Jidonsu
thumb.gif


OP is not giving us the info needed to configure system.

@SaintsEnd, we cannot give you specific answers to your extremely general and broad questions. Airflow is not a simple thing. Everything involved in system effects the path and rate the air flows. Even knowing all the assumed variables does not mean we can accurately predict what will work. It's like trying to predict the weather.
In addition to the fact that "static pressure" and "airflow" labels really don't mean anything in actual usage.....and that suction capabilities and static pressure are once again being confused.....
 

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Quote:
Originally Posted by ciarlatano View Post

In addition to the fact that "static pressure" and "airflow" labels really don't mean anything in actual usage.....and that suction capabilities and static pressure are once again being confused.....
Not that it matters, but how high and low pressure systems effect weather and weather forecasting is basically the same way airflow works in case cooling .. or maybe it does matter more than I want to admit.
tongue.gif
 

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Lets say we have a fan thats 100CMF and has 10Air pressure.
Its getting 50CMF with the current aplication

But with a fan that has 70CMF and has 15air pressure
Its getting the rated 70CMF in the application.

Therefore you would want to look for the fan that has 15 air perssure or more.
Every certain application has its own air resitance.
We need enough air pressure to be able to get max ratings.

having 99999CMF and 10 airpressure means your only going to get 50CMF in the application
Same performance as the 100CMF can
 

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Quote:
Originally Posted by Iwamotto Tetsuz View Post

Lets say we have a fan thats 100CMF and has 10Air pressure.
Its getting 50CMF with the current aplication

But with a fan that has 70CMF and has 15air pressure
Its getting the rated 70CMF in the application.

Therefore you would want to look for the fan that has 15 air perssure or more.
Every certain application has its own air resitance.
We need enough air pressure to be able to get max ratings.

having 99999CMF and 10 airpressure means your only going to get 50CMF in the application
Same performance as the 100CMF can
Exactly.

Unless the marketing material says "optimized for (static pressure or airflow)" and there are unregulated tests done to arrive at the specs on the box. In that case the fan has enough power to blow the Corsair sailboat across the Atlantic in complete silence, while having enough suction capability to take the state of Virginia with it.
rolleyes.gif
 

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Quote:
Originally Posted by ciarlatano View Post

Exactly.

Unless the marketing material says "optimized for (static pressure or airflow)" and there are unregulated tests done to arrive at the specs on the box. In that case the fan has enough power to blow the Corsair sailboat across the Atlantic in complete silence, while having enough suction capability to take the state of Virginia with it.
rolleyes.gif
Just leave Virginia where it is, but sink the sailboats. Won't take much of a leak in the hull to overpower their noisy bilge pump.
biggrin.gif
 

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High Air-flow will be better than High Static Pressire fans where there is no resistance to the air moving through the case.

In almost every situation however there is always a lot of resistance to air flow. Even if you don't have filters (which is just stupid) grills / components and wires get in the way - (also I bet your case isn't a tunnel, with intake at one end and exhaust at the other) any time the air has to change direction, that causes turbulance, which is also a restriction.

Consequently in almost every case, SP fans will give a better performance / noise ratio.

Identify SP fans by looking at the surface area of the fan blades. If you can poke your finger straight through the gaps in the blades, that's bad.
 

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Discussion Starter #16
So I'm wondering as well, if there is a way I can hookup tubes in a way that the fans can help move stuff through them...

Its generalized and broad because there is no actual system... yet... still need to find the right parts, moving oats and whatnot.

Also yes, I didn't realise static pressure didn't help with suction, thats probably the most important aspect of the fans that I need, The size of fan could be 120mm or 140mm

All the air is blowing from bottom to top.
 

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Quote:
Originally Posted by SaintsEnd View Post

So I'm wondering as well, if there is a way I can hookup tubes in a way that the fans can help move stuff through them...

Its generalized and broad because there is no actual system... yet... still need to find the right parts, moving oats and whatnot.

Also yes, I didn't realise static pressure didn't help with suction, thats probably the most important aspect of the fans that I need, The size of fan could be 120mm or 140mm

All the air is blowing from bottom to top.
ok... not sure if you are understanding what we are saying and still not sure what type of contraption you are trying to build so we are going back to the basics
smile.gif


CFM = cubic feet per minute. it's the rating of how much air is moved at the given rate. a 100 CFM fan will move 100 cubic feet volume of air (at STP or standard temperature and pressure) per minute with no airflow resistance. CFM rating is affect by the amount airflow resistance so the more airflow resistance it encounters (air filters, obstructions, etc) the lower the actual CFM becomes. however, the counter to air flow resistance is static pressure. if the air that is being moved is pushed by a high static pressure then the amount of reduction due to airflow resistance is minimized. so with high static pressure, the airflow resistance may only diminish the airflow by a small percentage instead of a large percentage.

static pressure is the amount of force the fan exert upon the air that is in the system. it is also the vacuum force applied on the intake side of the fan. static pressure is generally measured in pascal or PSI(pounds per square inch) or other measurements such as mm/h2o(millimeters of water) which is a variation of barometric pressure measurement that is measured in mm/hg or millimeters of mercury. computer fans generally use mm/h2o when giving static pressure information but occasionally you will be given other units of measure which you have to use google to convert the units.

so given that, if you have high static pressure, you will have a higher percentage of the rated CFM pass through the system. lets say you have a given airflow resistance (air filter) with a low static pressure fan, only 40% of the rated CFM has enough energy to overcome the airflow resistance of the air filter. however with a very high static pressure, the fan may generate enough pressure to push 90% of the rated CFM pass the same air filter. this is only a very basic illustration of why we need to know what kind of conditions and components we are working with so we can give you a best guess of what you may need. however if the project must remain undisclosed, we can only give you the information you need to make your own judgement of what needs to be done in your situation.
 

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To add some additional info to what psyclum said.

Static pressure is the maximum pressure the fan and push. In simple words this is the point the pressure stops the airflow. No air is flowing. None at all. Static is stopped, still, no movement. A totally worthless measurement.

CFM is almost as worthless. it is testing the fan as if we are going to use it to circulate air in a room Any time a fan is used in a computer there is resistance .. a grill, a filter, HDD cage, cables, fins, etc. The airflow to pressure curve (P-Q curve) gives us a much better representation of how a fan really flows air. Here is a link to some graphs and how they can be interpreted.
http://www.overclock.net/t/1491876/ways-to-better-cooling-airflow-cooler-fan-data/0_20#post_22644574
 
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