Staircase Design MCQ with answer and solution

Concept

The line of nosing is an imaginary line that touches the nosings of all treads and is parallel to the slope of the stair.

Step-by-step solution

1. The projecting edge of a tread is called the nosing. 2. An imaginary line joining all nosings, parallel to the stair slope, is called the line of nosing. 3. So the answer is (C).

Explanation

The nosing is the front projecting edge of each tread. The imaginary line through all the nosings, running parallel to the slope of the stair, is called the nosing line. Handrail height is measured vertically from this line.

Why the other options are wrong

A: Pitch is the angle of slope of the stair; 'pitch line' is sometimes used loosely for the same idea, but the standard term is line of nosing. B: A string is the sloping member that supports the steps, not an imaginary line. D: A railing is a physical handrail, not an imaginary line.

Shortcut

Joins the projecting edges (nosings) = Nosing line.

Common mistake

Choosing pitch line because both words relate to the slope of the stair.