A handrail is a rail that is designed to be grasped by the hand so as to provide stability or support. Handrails are commonly used while ascending or descending stairways and escalators in order to prevent injurious falls. Handrails are typically supported by posts or mounted directly to walls.
Similar items not covered in this article include bathroom handrails--which help to prevent falls on slippery, wet floors--other grab bars, used, for instance, in ships' galleys, and barres, which serve as training aids for ballet dancers. Guard rails and balustrades line drop-offs and other dangerous areas, keeping people and vehicles out.
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History of the handrail
The oldest known handrail was uncovered by French archaeologist Pierre St. Jamaine in an Assyrian ruin in southern Iraq in the city-state Nippur.
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British specifications
British Standard and British Standard Code of Practice are harmonized to European Normal (EN) series. Handrail height is set between 0.9 and 1 metre. Further details may be found on the UK government website.
Handrail dimensions (USA)
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 Act Standards for Accessible Design (ADASAD)--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 1¼" (32 mm) minimum and 2" (51 mm) maximum or a non-circular cross section with a perimeter dimension of 4" (100 mm) minimum and 6¼" (160 mm) maximum and a cross section dimension of 2¼" (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 6¼" (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 6¼ 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 1¾ inches (45 mm) below the tallest portion of the profile. The minimum width of the handrail above the recess shall be 1¼ inches (32 mm) to a maximum of 2¾ inches (70 mm). Edges shall have a minimum radius of 0.01 inch (0.25 mm).
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 2010 ADASAD 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.
Handrail clearance (USA)
The distance between the wall and handrail gripping surface is also governed by local code with the most common requirement being 1½" (38 mm) minimum. The National Fire Protection Agency (NFPA) and the Occupational Safety and Health Administration (OSHA) require that the distance between the wall and handrail be a minimum of 2¼" (57 mm).
The 1992 Americans With Disabilities Act Accessibility Guidelines (ADAAG) stated that there was to be an absolute dimension of 1½" between a handrail and a wall. This was actually a "grab bar" dimension which was part of the 1986 ANSI A117.1. ANSI changed the notation to 1½" minimum in 1990. This was not corrected in 2010 with the approval of the new ADASAD which now calls for a 1½" minimum (38 mm) clearance.
Codes also generally require that there be a 1½" clearance between the underside of the handrail and any obstruction--including the horizontal bracket arm. There is an allowance however for variations in the handrail size--for every 1/2" of additional perimeter dimension over 4", 1/8" may be subtracted from the clearance requirement.
Handrail strength (USA)
Handrails are to support a continuous load of 50 plf (75 kg-m) or a concentrated load of 200 pounds applied at the top of the handrail(90 kg).
ADA handrail height notations
Adult height requirements
Top of gripping surfaces of handrails shall be 34 inches (865 mm) minimum and 38 inches (965 mm) maximum vertically above walking surfaces, stair nosings, and ramp surfaces. Handrails shall be at a consistent height above walking surfaces, stair nosings, and ramp surfaces.
Children height recommendation
When children are the principal users in a building or facility (e.g., elementary schools), a second set of handrails at an appropriate height can assist them and aid in preventing accidents. A maximum height of 28 inches (710 mm) measured to the top of the gripping surface from the ramp surface or stair nosing is recommended for handrails designed for children. Sufficient vertical clearance between upper and lower handrails, 9 inches (230 mm) minimum, should be provided to help prevent entrapment.
Source of the article : Wikipedia
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