Constructing a building is an intricate process. If it's not built correctly, it can be a danger to its occupants.
For this reason, there are a variety of building codes put in place to ensure that a completed building is a safe building. One such set of building codes details the requirements of indoor stair railings.
Although the specifics of stair railing building codes differ by state, many are similar.
Handrail Requirements if Both Sides are Enclosed
Using the state of Washington as an example, a handrail is defined as a single pipe or bar affixed to the wall by brackets. Its use is to provide a handhold that's continuous for people who use the stairs.
For stairs less than 44 inches in width that are enclosed on both sides by walls or partitions, at least one handrail must be affixed to the wall. It is preferred that the handrail be placed on the right side of the staircase, as the person is going down the stairs; however, it is not mandatory in the state of Washington.
For staircases that are 44 inches and greater in width and are enclosed, both sides must have handrails, despite having walls or partitions on both sides.
Stair Railing Requirements when One or Both Sides are Open
Opposed to a handrail, a staircase railing consists of a vertical barrier, with a handrail attached to the top surface. For staircases less than 44 inches wide, in the state of Washington, if one side of the staircase is open, at least one stair railing must be constructed on that side.
For staircases with both sides open, a stair railing must be constructed on both sides. For staircases between 44 and 88 inches in width, a stair railing must be put in place on the open side.
For staircases greater in width than 88 inches, not only must the open sides have a stair railing installed, but stair railing must also be installed in the middle of the stair tread.
Stair Railing Specifications
Again, using the state of Washington as an example for building code requirements regarding indoor stair railing, as its codes are similar to those found across the country, the top rail of a stair railing must be a smooth surface material throughout the entire length. The vertical height of the stair railing cannot exceed 34 inches and cannot be less than 30 inches, when measured from the top rail to the forward edge of the stair tread.
The stair railing must be constructed to withstand a minimum of at least 200 pounds top rail pressure. When made of hardwood, the top rail must be at least 2 inches in diameter.
For top rails made of metal piping, the top rail must be at least 1 1/2 inches in diameter. When made of wood, posts of stair railing must be at least 2 inches by 4 inches dimensional lumber.
When constructed of metal pipe, the posts must be at least 1 1/2 inches in diameter.