If you take a lot of pride in your work or are working to detailed piping diagrams, you may find that the spacing of your offsets must be equal. Equally — spaced offsets are not only more attractive and more professional looking, they might required. You can guess and eyeball measurements to get them close, but you will need a formula to work with if you want the offsets to be accurate. Fortunately, I can provide you with such a formula, and I will.
Again, we will concentrate on 45°, 60°, and 22V2° bends, since these are the three most often used in plumbing and pipefitting. We will start with the 45° turns. In our example, you should envision two pipes rising vertically. Each pipe will be offset to the left and then the pipes will continue to rise vertically. For a visual example, refer to Fig. 2.6. It is necessary for us to determine uniform symbols for what we are doing, so let’s get that out of the way right now.
In our measurement examples, we will refer to Spread, the distance between the two offsetting pipes from center to center, as A. Set will remain with the symbol of S. Travel will be T and it will be the same as Distance of D. Run will be noted by the letter R. The letter F will be the length of pipe threads.
Now for the deal. Travel is determined in an equally-offset pipe run at a 45° angle by multiplying the Set by 1.414. Run is found by multiplying Set by
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FIGURE 2.6 ■ Two-pipe 45° equal-spread offset. |
1.000. The F measurement is found by multiplying the spread (A) by.4142. Remember that T and D are the same. Want to do the same exercise with a 60° setup? Why not?
To run a similar deal on 60° angles of equally — spaced offset pipes, you follow the same basic principles used in the previous example. Multiply the Set by 1.155 to find the Travel. Run is found by multiplying Set by.5773. The F measurement is found by multiplying the spread (A) by.5773. Remember that T and D are the same.
Need to find numbers for 22V2° bends? Well, it’s not difficult. To find figures for equally-spaced pipes with 22V2° bends, multiply the Set by 2.613 to find the Travel. Run is found by multiplying Set by 2.414. The F measurement is found by multiplying the spread (A) by.1989. Remember that T and D are the same.
