Where are miters started on a welded elbow?

• A. Center to center of welds
• B. From the inside of the pipe
• C. At the outer edge of insulation
• D. From the center of the elbow

Answer: (A)

When insulating a welded elbow, miters are started center to center of the welds. The weld lines mark where the pipe pieces actually join, so beginning the miter cuts along those centerlines lets the insulation pieces wrap and meet exactly at the weld seams. This alignment keeps the joints tight and continuous around the curved corner, which helps with thermal performance and a clean finish. Starting the miters from the inside or from the outer edge would not line up with the weld seams, and starting from the center of the elbow wouldn’t align the insulation with the actual joints.