Apprentice answer

What's the formula for finding the throat radius of a standard 90-degree elbow

2nd YearMeasuring, Layout & Field MathLearn / Reference

For a standard full-radius commercial elbow, the standard throat radius typically matches half the width of the turning duct dimension (R = \frac{W}{2}), unless high-velocity performance parameters require a full 1.5 \times D radius turn.

Ask a jobsite question Back to Measuring, Layout & Field Math

Plain-English answer

Field checklist

For a standard full-radius commercial elbow, the standard throat radius typically matches half the width of the turning duct dimension (R = \frac{W}{2}), unless high-velocity...

Ask Foreman

Hey boss, quick learning check: What's the formula for finding the throat radius of a standard 90-degree elbow? Is this the method you want used on this job, or is there a project-specific standard here?

Verify before acting

Use this as training guidance. The foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements always control the final answer.

Related questions in this category

How do I scale a drawing if the architect forgot to put dimensions on the mechanical room?2nd Year How do I locate the architectural grid lines to measure out my hanger locations?2nd Year How do we support vertical riser ductwork at each floor penetration?3rd Year What do I do if the structural beams shown on the print don't exist in the field?3rd Year How do I measure an offset when the duct has to drop 14 inches and move over 22 inches?3rd Year What is the Pythagorean theorem (A3rd Year