If a face-to-face measurement is given to the plumber, what is the next step?

If a face-to-face measurement is given to the plumber, what is the next step?

• A. Add for the actual pipe that goes into the fitting (thread take up)
• B. Deduct the fitting allowance from the center to center measurement
• C. Multiply by 1.414
• D. Ignore the center to center measurement

Answer: (C)

When you’re planning a layout that uses two fittings arranged at a right angle, you need the distance between their centers (center-to-center) rather than the distance between their faces (face-to-face). The centers sit along the diagonal of a square formed by the fittings, so the center-to-center distance is larger by a factor of sqrt(2). That means you multiply the given face-to-face measurement by 1.414 to obtain the center-to-center length. This step gives the correct length to lay out or cut the pipe for the connection. Other adjustments, like threading take-up or subtracting a fitting allowance, aren’t the immediate next step when converting from face-to-face to center-to-center.

When you’re planning a layout that uses two fittings arranged at a right angle, you need the distance between their centers (center-to-center) rather than the distance between their faces (face-to-face). The centers sit along the diagonal of a square formed by the fittings, so the center-to-center distance is larger by a factor of sqrt(2). That means you multiply the given face-to-face measurement by 1.414 to obtain the center-to-center length. This step gives the correct length to lay out or cut the pipe for the connection. Other adjustments, like threading take-up or subtracting a fitting allowance, aren’t the immediate next step when converting from face-to-face to center-to-center.