A question regarding the stair parts - What is the difference between a stair handrailing and a stair guard rail?

There really is not a difference. A guard rail has a handrail on it so they are really the same thing. All staircases must be designed to fit any guard-rail type building code. No spaces greater than 4 inches and no less than 36 inches tall.

Source: http://www.stairpartsblog.com