Calculating pressure of air pocket in a pressurized water column

[cvsanders]

TL;DR

Calculating pressure of air pocket in pressurized water column.

Looking for some guidance in calculating pressure of air pocket in pressurized water column. Example: 2" vertical pipe, capped, with 2" of air and 40 psi water applied.

 

[berkeman]

Welcome to PF.

Presumably the air bubble is at the top of the column, right? Where are you measuring the 40psi water pressure? At the top or bottom of the water column? How tall is the pipe?

 

[cvsanders]

Water supply line pressure is 40 psi, air is at top of 24" column, where it is being read.

 

[berkeman]

So the 24" tall pipe has 40psi water at the bottom. How much does the pressure drop going up that water column...?