Handrails are in place to provide guidance.

  Various model codes -- The International Code Council(ICC) and National Fire Protection Association(NFPA)-- and accessibility standards -- ANSI A117.1 and the Americans With Disabilities ActAccessibility Guidelines (ADAAG) -- refer to handrail dimensions. Current versions of these codes and standards now agree that handrail is defined as either a circular cross section with an outside diameter of 1-1/4" (32 mm) minimum and 2" (51 mm) maximum or a non-circular cross section with a perimeter dimension of 4" (100 mm) minimum and 6-1/4" (160 mm) maximum and a cross section dimension of 2-1/4" (57 mm) maximum. In addition, the International Residential Code (IRC) includes a definition of a "Type II" handrail that allows for handrail with a perimeter dimension greater than 6-1/4" (160 mm).

  The IRC and residential portion of the 2009 IBC define Type II handrail as follows: Type II. Handrails with a perimeter greater than 6-1/4 inches (160 mm) shall provide a graspable finger recess area on both sides of the profile. The finger recess shall begin within a distance of 3/4 inch (19 mm) measured vertically from the tallest portion of the profile and achieve a depth of at least 5/16 inch (8 mm) within 7/8 inch (22 mm) below the widest portion of the profile. This required depth shall continue for at least 3/8 inch (10mm) to a level that is not less than 1-3/4 inches (45 mm) below the tallest portion of the profile. The minimum width of the handrail above the recess shall be 1-1/4 inches (32 mm) to a maximum of 2-3/4 inches (70 mm). Edges shall have a minimum radius of 0.01 inch (0.25 mm).[1]

  Handrails are located at a height between 34" (864 mm) and 38" (965 mm). In areas where children are the principal users of a building or facility, the 2004 ADAAG recommends that a second set of handrails at a maximum height of 28" (711 mm) measured to the top of the gripping surface from the ramp surface or stair nosing can assist in preventing accidents.

ก่อน:Installation illustration of balustrade with glass sheet

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