Calculating CFM for Inline Fan - 420 CFM Minimum

  • Engineering
  • Thread starter markmess
  • Start date
  • Tags
    Cfm
In summary, when determining the minimum CFM required for an inline fan, you must multiply the number of openings by 60. However, the length and complexity of the duct system, as well as the fan's performance curve, will also affect the volume of air delivered. It is important to consider these factors when selecting the right exhaust fan for your needs.
  • #1
markmess
1
0
Homework Statement
I have no idea about this I am sorry to say but I don't know where to turn.
I was wondering if there is a formula to figure how much of a fan CFM is needed if I am running 80 feet of 3" PVC with 7 openings at the ends
Relevant Equations
I also need to know what happens when a inline fan that has (let's say) 600 CFM but it is made for a 10" duct connection and you reduce it down ( at the unit) to 3" in and 3" out? Or is there any difference if it is reduced to 3" in and I keep the 10" out?
I was told if I need 60 CFM at each opening multiply the mount of openings by the 60 and that would be the minimum of CFM inline fan I need. so 7 x 60 420 CFM but I need to figure if I reduce the pipe at the fan and how many feet it is running , if that has an effect?
 
Physics news on Phys.org
  • #2
Welcome, Mark!

Any fan is defined by two main things: how much volume of air it moves (CFM stands for cubic feet per minute) and how much static pressure it can generate inside a duct (inches of column of water in a U manometer).
Each fan follows a curve of performance, which is a series of points that define volume and pressure.

A long duct with many turns imposes certain amount of resistance to the flow of air (you need pressure to overcome that resistance).
For that combination, only certain volume of air will be delivered by that fan.

Please, see:
https://greenheck-cms-prod.azureedg...n-articles/perf_basics.pdf?sfvrsn=6df9b7ac_13

https://content.greenheck.com/public/DAMProd/Original/10002/FanFundamentals.pdf

https://www.grainger.com/know-how/e...per fan selection. ... 4 Sound Levels (Sones)
 

Related to Calculating CFM for Inline Fan - 420 CFM Minimum

1. What is CFM and why is it important for an inline fan?

CFM stands for cubic feet per minute and it is a measurement of the volume of air that an inline fan can move in one minute. It is important because it determines the fan's performance and its ability to effectively ventilate an area.

2. How do I calculate the CFM for my inline fan?

To calculate the CFM for your inline fan, you will need to know the size of the room or space that needs to be ventilated, the desired air changes per hour (ACH), and the efficiency of the fan. You can use a CFM calculator or the following formula: CFM = (Room Volume in cubic feet x ACH) / 60.

3. What is the minimum CFM required for an inline fan?

The minimum CFM required for an inline fan depends on the size of the room and the desired air changes per hour. However, for most residential and commercial applications, a minimum of 420 CFM is recommended for efficient ventilation.

4. Can I use a fan with a higher CFM than the recommended minimum?

Yes, you can use a fan with a higher CFM than the recommended minimum. In fact, it is often recommended to choose a fan with a higher CFM to ensure proper ventilation and to compensate for any obstructions or ductwork that may decrease the fan's performance.

5. Is there a maximum CFM for an inline fan?

There is no specific maximum CFM for an inline fan. However, it is important to choose a fan with a CFM that is appropriate for the size of the room and the desired air changes per hour. Using a fan with a much higher CFM than necessary can lead to excessive noise and energy consumption.

Similar threads

Do Dual Fans Increase Radiator Efficiency More Than a Single Larger Fan?
    • Mechanical Engineering
Replies
6
Views
710
Comparetto type Air Cleaner/Filter: What causes its increased airflow?
    • General Engineering
Replies
5
Views
2K
Calculating CFM Needed to Move an Object of 2lbs
    • Mechanical Engineering
Replies
8
Views
5K
How can adjacent air be accounted for in fresh air exchanges for HVAC systems?
    • Mechanical Engineering
Replies
4
Views
1K
Need help with a research project for firefighting
    • Mechanical Engineering
Replies
7
Views
1K
Calculating Airflow Decrease of Backward Inclined Centrifugal Fan
    • Mechanical Engineering
Replies
3
Views
1K
Automotive Velocity vs Volume in the intake
    • Mechanical Engineering
Replies
6
Views
4K
CFM calculation with a known fan and different inlet and outlet areas
    • General Engineering
Replies
1
Views
4K
Calculating CFM based on Power Dissipation and Max Junction Temp
    • Electrical Engineering
Replies
1
Views
2K
Calculating Heat Loss in Pipes with Air Flow and Water Surrounding
    • General Engineering
Replies
15
Views
4K

Hot Threads

Recent Insights

Back
Top