What is a Pipefitting Takeoff? | Understanding the Basics of Pipe Measurement

 What is a Pipefitting Takeoff? | Understanding the Basics of Pipe Measurement

In pipefitting, precision is critical, and knowing how to measure pipes and fittings accurately is essential. One of the most important concepts in this process is the **pipefitting takeoff**. This guide will walk you through the basics of pipefitting takeoffs, focusing on 90-degree elbows, 45-degree elbows, and flanges.

 What Is a Pipefitting Takeoff?

A **pipefitting takeoff** refers to the section of pipe that is subtracted or "taken off" from a straight pipe to accommodate fittings like elbows, tees, or flanges. This ensures that the final length of the pipe is accurate when the fittings are installed. 

Takeoffs are essential because, when fittings like elbows are added, the direction of the pipe changes, which alters its length. By subtracting the fitting's takeoff value, you can maintain the correct overall pipe length in your piping system.

 Takeoff for a 90-Degree Elbow

Let’s start with the most common fitting: the **90-degree elbow**.

- For a **6-inch long radius 90-degree elbow**, the takeoff is typically **9 inches**. 

- The takeoff is measured from the end of the pipe to the center of the elbow’s curve.

  

To calculate this:

1. Start with the nominal pipe size (in this case, 6 inches).

2. Divide it by two, giving you 3 inches.

3. Add these two numbers together (6 + 3 = 9 inches).

This gives you the **takeoff** for the long radius 90.

 Long Radius vs. Short Radius 90s

There are two types of 90-degree elbows: **long radius** and **short radius**.

- The **long radius 90** has a larger curve and, as we calculated, a larger takeoff.

- A **short radius 90-degree elbow** has a tighter curve, resulting in a smaller takeoff. For a 6-inch short radius elbow, the takeoff is equal to the **nominal pipe size**, which is **6 inches**.

 Takeoff for a 45-Degree Elbow

A **45-degree elbow** is essentially half of a 90-degree elbow, so its takeoff is calculated differently.

To calculate the takeoff for a 6-inch 45-degree elbow:

1. Start with the nominal pipe size (6 inches).

2. Divide it in half (3 inches).

3. Divide it in half again (1.5 inches).

4. Divide it in half one more time (0.75 inches).

  

Now, add these values together: 3 + 0.75 = **3.75 inches**. So, the takeoff for a 6-inch 45-degree elbow is **3.75 inches**.

 Takeoff for Flanges

Flanges are another common fitting in piping systems, and the process for calculating their takeoff is straightforward, especially if you have access to the actual fitting.

For a **6-inch 150 flange**, you can measure the takeoff by using a tape measure from the inside of the flange to the face. This particular flange has a takeoff of **3.5 inches**.

 Tools for Finding Takeoffs

While it’s possible to calculate takeoffs manually, there are several tools that can make the process easier:

- **Pipefitter's Blue Book:** A comprehensive reference guide that includes takeoff values for various fittings.

- **Chico Cards:** Handy reference cards for pipefitters, showing takeoff values for different fittings and sizes.

- **Piping Selector Wheel:** A tool where you can point an arrow at the fitting, and it will show the corresponding takeoff for the given pipe size.

 How to Use These Tools

1. **Pipefitter's Blue Book:** Turn to the appropriate page (e.g., Page 95 for long radius 90s). Look for the nominal pipe size and the letter indicating the type of fitting (e.g., "A" for long radius 90s). Follow it down the chart to find your takeoff.

  

2. **Chico Cards:** On Page 7A, look for the fitting type (e.g., long radius 90), then find your pipe size in the chart, which will show the takeoff.

3. **Piping Selector Wheel:** Point the arrow at the fitting type (e.g., long radius 90) and align it with your pipe size to find the takeoff value.

 Flange Classifications

Flanges come in different classes, such as 150, 300, 600, or 900, and each class has a different takeoff value. As the rating increases, the flange becomes thicker, and the takeoff value changes. 

For example, the takeoff for a **6-inch 150 flange** is **3.5 inches**, while a **6-inch 300 flange** has a takeoff of **3.875 inches**. Always be sure to check the flange's classification, which is typically stamped on the outer edge of the flange.

 Conclusion

Knowing how to calculate takeoffs is essential for accurate pipefitting. By understanding the takeoff values for different fittings like 90-degree elbows, 45-degree elbows, and flanges, you can ensure precise measurements in your piping projects. 

Whether you use manual calculations or rely on reference tools like the Blue Book, Chico Cards, or a Piping Selector Wheel, mastering takeoffs is a critical skill for any pipefitter.

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