1-     How can I calculate head loss and air velocity of air in a 12” round duct at 1000 cfm in Modern mode?

 

First go to setting and select the following units:

·       Duct Type: Round

·       Flow Rate: cfm

·       Head loss: in/100ft

·       Duct size: in

·       Velocity: fpm

Then go to “Modern” mode, select “pressure drop”, then turn the flow rate wheel to 1000 cfm and Round Size in to 12”. Head loss and velocity will be 0.197 in WG/100 ft and 1273 fpm respectively.

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2-     How can I calculate the round duct size for 1200 cfm for friction loss of 0.06 in WG/100ft?

 

Set the units as the previous question and in Modern mode select “Duct size Head Loss”.

Set the temperature, relative humidity and altitude as your project specifications, then set the flow rate wheel to 1200 cfm and head loss wheel to 0.06 in WG/100ft, round size will be 16.44”.

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3-     I need to calculate round duct size for 1500 cfm, the duct sizing criteria is velocity limit for 800 fpm.

 

Set the units as the previous question and in Modern mode select “Duct size Velocity”. Set the temperature, relative humidity and altitude as your project specifications, then set the flow rate wheel to 1500 cfm and velocity wheel to 800 fpm, round size will be 18.54”.

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4-     How can I calculate the round duct size for 1391 cfm for 0.11 in WG/100 ft?

 

Set the units as the previous question and enter “Classic D” mode. Fill out the “Flow rate” and “Head loss” for 1391 cfm and 0.11 inWG/100ft. Duct size will be 15.32 in.


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5-     How can I calculate head loss and velocity of 16.5” round duct at 1890 cfm?

 

Set the units as the previous question and enter “Classic ΔP” mode. Fill out the “flow rate” and “Round Size” for 1890 cfm and 16.5 in. Head loss and velocity will be 0.134 inWG/100ft and 1272.82 fpm respectively.

 

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6-     How can I calculate head loss and velocity of 12”X20” for flow rate of 2000 cfm?

 

Set the units as the previous question except “Duct Type” which is “Rectangular” and in Modern mode select “Pressure Drop”.

Set the flow rate wheel at 2000 cfm and width and depth at 12” and 20” respectively.

Round duct size, head loss and velocity will be 16.8”, 0.136 inWG/100ft and 1299.35 fpm respectively.

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7-     How can I calculate the size of a rectangular duct for 2800 cfm at head loss of 0.08 inWG/100ft (depth is 10”)?

 

Set the units as the previous question and in Modern mode select “Duct Size Head Loss”.

Turn the “Head Loss” wheel and set it for 0.08 inWG/100ft, now you have a rectangular duct size with almost same width and depth, which are 19”X19” with round duct size of 20.77”.

Then turn the “Depth” wheel to reach 10”, and you will see the “Width” wheel turns automatically and show 41”!

 

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Results with same width and depth

 

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Results with desired depth!

 

 

8-     How can I size a rectangular duct with the criteria of velocity not exceeding 1200 fpm for 3200 cfm (width is 26”)?

 

Set the units as the previous question and in Modern mode select “Duct Size Velocity”.

Turn the “Velocity” wheel and set it for 1200 fpm, now you have a rectangular duct size with almost same width and depth, which are 20”X20” with round duct size of 21.86”.

Then turn the “Width” wheel to reach 26”, and you will see the “Width” wheel turns automatically and show 16”!

 

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Results with same width and depth

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Results with desired depth!

 

9-     How can I size a rectangular duct for flow rate of 5120 L/s with the head loss criteria of 3 Pa/m (width is 500 mm)?

 

 First go to setting and select the following units:

·       Duct Type: Rectangular

·       Flow Rate: L/s

·       Head loss: Pa/m

·       Duct size: mm

·       Velocity: m/s

Then go to “Classic D” mode, and enter the flow rate and head loss, now you will see the calculated round size which is 676.35 mm. After that you can fill out the “Width” with 500 mm. 775 mm will emerge as “Depth” and “Round Size” will update to 676.45 mm.

 

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Round size has been calculated!

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Now you have Depth after entering Width or vice versa.

10-  I have a flow rate of 1258 L/s for a 350 mm X 550 mm duct, how can I calculate the head loss, velocity and round duct size?

 

Set the units as the previous question and enter “Classic ΔP”. Fill out flow rate, width and Depth according to your preferences. Round Size, Head Loss and Velocity will be calculated.

 

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