Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Components (hierarchy name)
4. components (objects parts)
5. [components by general context]
6. [joints and joint components]
7. joints (connections)
8. [joints by material joined]
9. metal joints
10. metal seams

Anotations

Scope note:

Distinctive sheet metal seams made with one sheet edge turned, double-bent, and locked onto a sheet having a simple bend; usually created using a special Pittsburgh lockforming machine. An example of use for the seam is at the corners of elbows and square or rectangular pipes of ducts.