Rolling Offsets (run)

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Equation / Last modified by KurtHeckman on 2017/01/17 17:32
Rolling Offsets (run)
Variable Instructions Datatype
`(U)"vertical offset"` Enter rise or fall offset Decimal (in)
`(S)"horizontal offset"` Enter left or right offset Decimal (in)
`(fA)"fitting angle"` Enter the angle of the fitting (e.g. 45, 60, or 22.5 degrees) Decimal (°)
`(oC)"Run or Travel"` Choose to compute Run (R) or Travel (T). Text
4 variables
KurtHeckman.Rolling Offsets (run)

The Rolling Offset calculator computes the length of the run (R) or travel (T) based on the vertical (U) and horizontal (S) offsets and the fitting angles (fA) of the elbow fittings.  For just the travel (T) in the diagram choose Travel (T) as the oC or click Rolling Offset (Travel) plumbing1.png             Rolling Offset  of Pipes or Conduit .

YouTube Video Instructions

INSTRUCTIONS: Choose your preferred units and enter the following:

  • (U) - Vertical offset
  • (S) - Horizontal offset
  • (fA) - This is the elbow Fitting Angle.  (45o, 60o,  90o,and 22.5o are most common)
  • (oC) - Choose run (R) or travel (T).

Rolling Offset: The calculator will return the run (R) or travel (T) in inches.   However, this can be automatically converted to other length units (e.g. centimeters or feet) via the pull-down menu.


 When running pipes or conduits, it is common to have to change the run of the line of pipes by using two equal angled elbow fittings (see diagram).  The length of the run (R) and travel (T) created with the elbows and the length of pipe between them, can be calculated if one knows the vertical and horizontal offsets and the angle of the fitting.  

The Math

In the diagram above, the relationship between the travel length and the offsets is as follows:

                                             ` x = sqrt( U^2 + S^2)`

                                              ` T = x / cos (90 - fA)`

                                               `R = sqrt(T^2 - x^2)`

Note: vCalc allows for multiple units for both length (SI and English) and for angles (degrees and radians).  The result will be in inches.  However, this can automatically be converted to other length units (e.g. centimeters) with the pull-down menu.

See Also


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