Code requirements for exterior handrails are designed to guarantee health and safety standards for people using stairs. Handrails provide users with support and balance. Code requirements for handrails on exterior stairs are similar to those of inside stairs. Code requirements are a starting point for designers and builders. If the use given to stairs and their context require it, include additional handrails and improve safety measures.
Handrails should be should be installed so the top of the handrail is between 34 and 38 inches from the edge of the stair.
Handrails must run the whole length of the stair from the top step to the bottom. According to the Seattle Department of Planning and Development, handrails must extend at least 12 inches beyond the top and bottom riser. This increases safety on the two most dangerous places on a stairway: the top and the bottom ends.
Number of Handrails
Any flight of stairs with four or more risers must have a handrail on at least one side. Every section of a stair must be within 30 inches of a handrail. This standard might require you to install intermediate handrails along wide stairs.
Returns and Safety Stops
Builders must attach a return to the end of handrails or connect them to a post or pillar. This avoids people catching their clothes or bumping into the end of handrails.
Handrails must have a maximum width of 1 1/4 to 2 inches in diameter. Handrails with a perimeter -- the sum of the length of the sides of an object -- of up to 6 1/4 inches must have a maximum width of 2 1/4 inches. If the perimeter is larger than 6 1/4 inches, the handrail must have a finger recess area to improve grip on the handrail.
The handrail must be separated enough from the wall, or any other object to allow a pedestrian to get a firm grip. The minimum gap is 1 1/2 inches.