Stair Construction Regulatory Requirements Stair Construction Regulatory Requirements
There are varying specifications and building codes for stair construction for different municipalities, but most are similar. Experts have evaluated the best way to construct stairs to avoid accidents like tripping and rail collapses. If you are building a stairway for an emergency exit system, the regulations are very specific and strict because they must be safe for people to exit a building in an emergency. The Americans with Disabilities Act also has standards for stairway construction with regards to accessibility for people with disabilities, especially to allow them proper access and egress in the case of an emergency.
Specifications for Treads, Risers and Nosings
The main part of the stair, the part you step on, is called the tread. This is the width of the stair. The riser is what supports the tread and determines the height of the step. There are also staircases that are built with no rises, where the stairs are suspended. The nose is the edge of the step that overhangs the riser. For a stir without a rise, this is called the back-slope.
Overall staircases should not have a steepness or slope of more than 35 degrees. All risers must be the same height. The stairway width is determined by the potential occupant load. For 50 people of more this must be at least 44 inches. For occupancy of 49 people or less, the width must be at least 36 inches. The depth of an individual tread must be a minimum of 11 inches. The nose can overhand at most, 1 1/2 inches.
Specifications for Handrails and Guardrails
Handrails or guardrails are the barriers that run along the side of the staircase. These safety devices are required in commercial or public buildings on both sides of a staircase. The height of the rail must be 34 to 38 inches above the nose or tread of each stair. In a commercial stairway, there must be multiple guardrails in the open space between the handrail and the stairs. The space between individual guardrails cannot exceed 4 inches in order to protect children from falling through.
Specifications for Landings
A landing is the floor that is above and below a stairway. The landing cannot be less than the width of the stairway and has a requirement of at least 44 inches in length in public and commercial structures. In a private dwelling, the landing must be at least 36 inches long. For curved stairways, the landing must be wider than the stairway in the path of travel. If there is a door which opens onto the stairway landings, it cannot extend over 7 inches into the landing and is not allowed to shorten the width of the landing by more than half. There are also guardrails for landing and before installing one; you should also check specifications and regulations for this type of rail.