CO2/Nitrogen (beergas) Line length formula

[Dirk McLargeHuge]

I'm getting a little more foam on my beergas line than I want.

Make that line longer.

You could also check http://www.draughtquality.org/f/DBQM_Full.pdf. There are "documented formulas" in there.

[dunleav1]

Dirk,

I wasn't blowing you off, I read the document the first time you posted it. There's a lot of good info in there, thanks for posting it.
Chapter 5 Example 2 kind of goes into the issue and gives an example but based on my setup and the example it just doesn't make sense to me.

I know I need a longer line, but I'd like to be in the ballpark of how much I need. I can just buy a bunch of line but I'd like to do the math.

I can use 3/16" or 5/16" line but I'd rather use the least amount of tubing so it's neater.
My vertical lift is 2'.
My beergas mix is 75% Nitro, 25% CO2.

[Quin]

What is your serving temperature?

[dunleav1]

40 degrees.

[Quin]

Dirk,

I wasn't blowing you off, I read the document the first time you posted it. There's a lot of good info in there, thanks for posting it.
Chapter 5 Example 2 kind of goes into the issue and gives an example but based on my setup and the example it just doesn't make sense to me.

I know I need a longer line, but I'd like to be in the ballpark of how much I need. I can just buy a bunch of line but I'd like to do the math.

I can use 3/16" or 5/16" line but I'd rather use the least amount of tubing so it's neater.
My vertical lift is 2'.
My beergas mix is 75% Nitro, 25% CO2.

OK. I think I understand now.
For 20 psi and 3/16" ID tubing at 2.2 psi/ft you would need 9 ft
at 3.0 psi/ft you would need 7 ft

For 20 psi and 1/4" ID tubing at 0.65 psi/ft you would need 31 ft
at 0.85 psi/ft you would need 24 ft

For 20 psi and 5/16" ID tubing at 0.40 psi/ft you would need 50 ft
at 0.50 psi/ft you would need 40 ft

I would buy 12' of 3/16". I'm using 12' -3/16 at 35°and 20 psi for a strong golden ale at 3.5 volumes and it works great.

The statement on Micromatic.com about not using 3/16" for lines over 5' is for CO2 in for standard range of CO2 volumes, temp, and pressure.

Also you still need to enter the chart at the regulator pressure (not regulatorx25%) and temp. You apply the 25% to the volumes of CO2 in solution.

So for 20 psi and 40°F and 100% CO2, you would get 3.19 volumes.
For beergas at 25% CO2, 0.25x3.19 = 0.8 volumes

[dunleav1]

This is just what I was looking for.
Thanks!