Direct Answer
Steel shop drawings use a building coordinate system — North direction, column grid, and floor elevation — to locate every member. On piece mark drawings, the 'North' face or 'erection orientation' is called out to ensure the member is installed the correct way. Piece marks oriented incorrectly in the field are one of the most common erection problems.
Full Explanation
The building coordinate system is established by the engineer in the general notes or on a site plan. Grid lines are labeled numerically (1, 2, 3 — typically in one direction) and alphabetically (A, B, C — in the perpendicular direction). Elevations are defined from a datum (finished first floor, site benchmark, etc.). On column piece mark drawings, the 'A-side' or 'North face' is called out to indicate which face of the column faces a specific direction — this is critical for asymmetric connections.
What This Means for Your Shop
Mark the North face (or A-side) of every column during fabrication with a permanent paint mark or stencil. When the ironworker sets the column, they can orient it correctly before plumbing without referring to drawings in the field.
Common Mistakes
Shipping columns without orientation marks, forcing ironworkers to figure out which face is which in the field by referencing drawings — a slow and error-prone process, especially for large columns with multiple connection faces.
Recommended Process
Include orientation marking in your fabrication and shipping procedures. After all connections are welded and the column is inspected, apply a permanent orientation mark (paint, stenciled letter, or scribed line) to the top-of-steel or North face before shipping.