Rolling Offset Calculator - Piping offset calculation 45&90 degrees

Horizontal Offset:

Vertical Offset:

Bend Angle of Fittings (°):

True Offset (cm):

True Offset (ft):

Travel Length (cm):

Travel Length (ft):

Run Length (cm):

Run Length (ft):

1. What is a Rolling Offset Calculator?

Definition: A rolling offset calculator determines the pipe length needed to connect two pipelines offset both horizontally and vertically using elbow fittings.

Purpose: This tool helps pipefitters calculate the travel and run lengths for accurate pipe installation, as demonstrated in the example below.

2. How Does the Calculator Work?

Let’s say we want to connect two pipelines offset horizontally by 100 cm and vertically by 50 cm using 45-degree elbows. Here’s how we calculate the rolling offset:

First, find the true offset (the straight-line distance between the pipe ends):

\[ c = \sqrt{h^2 + v^2} = \sqrt{100^2 + 50^2} = \sqrt{10,000 + 2,500} = \sqrt{12,500} = 111.80 \, \text{cm} \]

Next, calculate the travel length (the pipe length needed):

\[ T = \frac{c}{\sin(\theta)} = \frac{111.80}{\sin(45^\circ)} = 158.11 \, \text{cm} \]

Then, determine the run length (the horizontal projection):

\[ R = \frac{c}{\tan(\theta)} = \frac{111.80}{\tan(45^\circ)} = 111.80 \, \text{cm} \]

We can also calculate the advance length (the vertical component of the travel):

\[ A = T \times \cos(\theta) = 158.11 \times \cos(45^\circ) = 111.80 \, \text{cm} \]

Additionally, the relationships between these lengths can be expressed as:

\[ T = \sqrt{R^2 + A^2} \] \[ R = A \quad (\text{when } \theta = 45^\circ) \]

Explanation: The true offset is the hypotenuse of the offsets, travel is the pipe length adjusted by the bend angle’s sine, run is the horizontal distance via tangent, and advance is the vertical rise via cosine. For 45° elbows, run equals true offset and advance, as shown. Results are provided in both cm and ft for convenience.

3. Why Use This Calculator?

Details: It simplifies pipefitting by providing precise measurements in multiple units (cm and ft) for any bend angle (e.g., 45°), ensuring correct pipe cuts and fittings.

4. Preparing for Pipe Installation

Tips: Measure horizontal and vertical offsets, choose a bend angle (e.g., 45° as in the example), and use the travel length (in cm or ft) to cut your pipe accurately.

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