question about take offs

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i have a question about the take off on pipes.  if i am correct i think the take offs are 1.5 for a 90 and 1 time the diameter for a 45.  if this is correct i would like to know what does this mean does it mean that i take 1.5 time the diameter of the pipe off of the pipe for a 90           ex.   10 foot 6 inch pipe install a 90 degree ellbow it becomes a 9 foot three inch pipe before the elbow  also are there any other take offs i should know about????
Reply:Casey,The take-off all depends on the radius of the fitting (90* elbow).Here's a quick method that I have used for many years in the pipe fitting industry and when teaching apprentices.Instead of taking the time to figure out all the math the long way, just remember this quick method. For long radius 90's, the take off is always 1-1/2 times the diameter of the fitting.Example: A 6" long radius 90 takes off 9" (6"+3" = 9"). So if you're going to add a 6" LR 90 to a piece of pipe and you want a total length of 5'-10" from end of pipe to center of 90* elbow, you would cut the pipe 5'-1" long.A 6" short radius 90 takes off 6" (diameter is 6", the take-off is 6"), so if you're going to add a 6" SR 90 and wanted to get the same end to center length, 5'-10", as in the example above, you would cut the pipe 5'-4" long. Now for the take-off of a 45* elbow.It doesn't matter what size pipe you're using, this method always works, on all standard made 45's, no matter what the wall or schedule thickness is.Take the diameter of the fitting, say 12", and divide the diameter in half 3 times; i.e. 12", 6", 3",1-1/2".Take the second and forth numbers and add them together and your takeoff answer will be 7-1/2".24" would be, 24", 12", 6", 3". Answer 15" 6" would be, 6", 3", 1-1/2", 3/4". Answer 3-3/4" 10" would be, 10", 5", 2-1/2" 1-1/4". Answer 6-1/4"This example is for WELDED PIPE ONLY. Threaded pipe is different.As for other fittings like weld neck flanges, the take-off depends on the diameter of the flange and the rating, i.e. 150#, 300#, 600# etc.There is also different take-offs for different sizes of Tees, Y's and laterals.The above examples I've used, only work for 90's and 45's, no matter the size.Hope this helps.Last edited by Diverbill45; 09-28-2006 at 03:49 AM.
Reply:thank you greatly