How can stair dimensions be identified on blueprints?

Stair dimensions on blueprints are most accurately identified using rise and run measurements displayed alongside the stair layout. This method provides precise numerical values that indicate how steep the stairs are (rise) and how far they extend horizontally (run). These measurements are critical for ensuring that the staircase complies with building codes and provides safe usage for occupants.

The other options, while relevant to different contexts, do not provide the same level of clarity regarding stair dimensions. For instance, color coding may be useful for visual differentiation but lacks the specific numerical data needed for accurate construction. Labeling the number of stairs gives a count but does not inform builders of the necessary dimensions for safety and compliance. Rough estimates in a key can lead to inaccuracies that could affect design and function, thus making precise rise and run measurements the optimal and most reliable choice for understanding stair dimensions on blueprints.