UBC Stair & Railing Codes

History

• Both municipal and state building commissions in the West adopted the UBC almost universally either directly or with some changes. However, other building codes remained in force. The UBC was updated until 1997. In 1994, the International Conference of Building Officials, among other organizations, established the International Code Council. This new council consolidated existing codes and eliminated duplication to create the International Building Code, which has since supplanted the UBC, and is now in wide use by local, state and some federal entities.

UBC Stairs

• The 1997 edition of the UBC defined stairways and railing codes in over two, two-column pages beginning at section 1003.3.3. Among the requirements were minimum stair widths of 36 inches, for occupant loads of under 50, and 44 inches, for occupant loads of 50 or greater. Risers between steps measured from 4 to 7 inches and could not vary by more than 0.375 inches across an entire flight of stairs. Stair treads could not vary by the same amount and needed to be a minimum of 11 inches deep. Headroom above each tread had to be at least 80 inches.

UBC Handrails

• Section 1003.3.3.6 of the 1997 UBC defined most handrail specification. It specified that handrails on either side of the stair could not project more than 3.5 inches into the step. Stairways that were 88 inches or wider needed one intermediate handrail for each 88 inches. These additional rails had to be spaced equally across the entire width of the stairway. The height of the handrails had to be from 34 to 38 inches as measured above the tread edges and landings. The rails had to continue throughout the full length of the stairs.

IBC Stairs and Handrails

• The current 2012 International Building Code takes many of its specifications for stairs from the 1997 UBC. For example, the height of handrails remains the same at from 34 to 38 inches. These rails also need to continue throughout a flight of stairs. Headroom above the treads is a minimum of 80 inches. Stairways need a minimum width of 36 inches, for loads under 50 occupants, and 44 inches for loads of 50 occupants and above.