You’ve just seen how to get around what many would see as a typical problem. Most offsets are used to get around square or rectangular objects. But, what happens when you have to bypass a round object, such as a pressure tank? Don’t worry, there is a simple way to get around most any problem, so let’s talk about going around circular objects.
Okay, we have a pipe that has to rise vertically, but there is a horizontal expansion tank hanging in the ceiling that is blocking the path of our pipe. We have a very limited amount of space on either side of the tank to work
within, so our measurements have to be precise. Assume that an eyeball measurement will not work in this case. So, let’s set up the symbols that we will use in this formula.
Let’s use the letter A to indicate the center of the offset rising pipe from the center of the expansion tank. The letter B will represent the center of the offset rising pipe from the edge of the tank. One-half of the diameter of the tank will be identified by the letter C. We will use the letter D to indicate the distance from the center line of the tank to the starting point of the offset. Additional information needed is that A = B + C and D = A X.4142. See Fig. 2.8 for a drawing to help you visualize the setup.
To put the letters into numbers, let’s plug in some hypothetical numbers. Assign a number of 18 inches to C and eight inches to B. What is D? Here’s how it works. A = B + C = 8 + 18 = 26 inches. D will equal A X.4142 = 26 X.4142 = 103/4 inches. This makes the center of the fitting 103/4 inches from the center of the tank.
