Field-Verify Throat, Heel, Centerline, Rise, and Run Before Releasing a Fitting

Fast answer

Record the fitting from clear control points and identify exactly which dimension is throat, heel, centerline, rise, run, and straight length. The shop should not have to guess how your field numbers relate to the fitting.

What to check

1. Sketch the fitting in the same viewing direction used for installation.
2. Mark airflow, top, and the reference end.
3. Dimension from stable faces or centerlines and label each number.
4. Add connector type, duct size, and any straight needed before or after the fitting.

Do not

Do not send a list of unlabeled dimensions or mix inside, outside, throat, heel, and centerline measurements on one sketch.

Ask the foreman

“I sketched this offset looking downstream, marked top, and labeled throat, heel, rise, run, and both connector ends. Can you check the field release before I send it to the shop?”

Why it matters

Clear fitting dimensions prevent mirrored, shortened, or unusable remakes.