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Stair & Ramp Safety
“Watch Your Step & Hold On!”, Pg.4
Related: Stair Nomenclature Diagram
- Table of Contents
Stair and Ramp Glossary
By Alvin & Lawrence Ubell
- (Also known as Banisters.) A series vertical pillars, sticks, dowels, spindles or struts forming part of, and being the supporting elements of a guardrail or handrail. Balusters should be safely spaced to prevent incidents involving children slipping through the balusters or getting their head caught.
- Balustrades or Guardrails:
- Horizontal railings or barriers at the edge of stairwell openings, balconies, or terraces to prevent persons from falling into the opening below. It should not be less than 42″ inches high and should have sufficient lateral and vertical strength to support the impact of the designed occupancy load of the space being protected.
- Doors at Stairs:
- Shall not swing into or out over a stair and should not block or reduce the width of the stair in any way. Doors shall not block platform, landings, corridors or hallways that lead to or from any stair.
- Floor or Landing:
- A space, at the main work area of a structure or stories of a building.
- Flight of Stairs:
- A run of steps or a combination of stair runs with intermediate platforms between landings, floors or stories.
- A straight line or flight of stairs from storey without intermediate platforms. Flights of stairs that are very long (more 15 to 20 risers) cause some people to experience vertigo and they will not use them. Most accidents occur at the top or bottom sections of stairs. The first four steps at the foot or head are the most critical. Stairs with one or two risers have been associated with incidents; some building standards require at least two, three or more risers in any one flight. When the elevation is too low to accommodate more than two or three steps, a ramp is recommended.
- Handrail or Stair-Rail:
- A narrow railing to be grasped with the hand for support; a guiding rail that runs parallel to the rake or angle of a stair. It enables one to grasp for stability and in the event they falter. Handrails must be ergonomically designed for height and holding ability, placed and secured so one can fully grasp and have space for their fingers/hands and to support their weight. The optimum diameter of a handrail is 1½″ inch. Wide stairs require handrails on both sides and very wide stairs require intermediate handrails. Handrails also act as a visual-cue, to indicate that there is change in elevation and that a stair or ramp is present. Every stair, whether it is a single step or multiple steps, requires a handrail.
- The upper or head supporting of members in construction framing of a stairwell for the leaning and supporting section of a stair.
- The distance from the rake or tread of the stair or ramp to the lowest overhead obstruction. This measurement must be ergonomically designed to prevent head injuries. 6′ foot 8″ inches is standard; 7′ foot 6″ inches is optimum under present standards.
- Kilt or Wash of Treads:
- For exterior stairs only. Stairs that are subject to the elements require that the tread be slightly tilted downward toward the nosing to permit it to drain.
- Newel-Post or Baluster-Post:
- The top or bottom supporting post of a stair-rail, handrail or guardrail.
- The front leading edge of a tread. Some step treads do not have an over hang nosing.
- Open Riser Stair:
- A stair design where there is no solid riser and all that is visible is the treads, handrail, and guardrail and support elements.
- Psychomotor Function:
- The complex series of mental and physical events that makes repetitive activity possible.
The complex repetitive activity in which a person quickly and accurately calculates the necessary
motor coordination movements for walking, running, jumping, and any and all repetitive motor
function such as stair and ramp climbing and descending.
Where a stair is involved, the user unconsciously sets up the stride or pace based on the prior action that will be used during the total ascending or descending action. One could almost say that when a person is climbing up or walking down a set of stairs/ramp, the user is on autopilot.
When the surface condition, stair, ramp or ladder encountered by the individual is different or inconsistent than expected from the previous gait, stride or experience, (for example: irregular, out-of-stride, out-of-level, out-of-geometry, non-constant, slippery) an accident may happen. The necessary gait or stride adjustment within the individual may not occur or be reestablished fast enough for the user to gain their equilibrium. Hence, the descender or ascender loses their balance.
- The space where generally two runs of stairs or set of steps intersect at an intermediate section between stories, floors or landings.
- Inclined plane or surface connecting different levels; a stair without a riser(s) to create a smooth, ascend or descend interface between two elevations to enable a person to climb without interruption and to permit the use of wheeled carts, chair or vehicles. Ramp should be of a non-slip surface. All ramps that have a rise greater than 1″ inch every 12″ inches run must have handrails. Ramps with a rise greater than 1½″ inch every 12″ inches of run have proven to cause slip incidents and require extra effort to ascend, particularly for the elderly and disabled. Wide ramps require handrails on both sides. Ramps with open sides must have a handrail or guardrail on the open side. In the design of ramps and to reduce ramp incidents, follow the specifications as set forth by the Americans with Disabilities Act (ADA).
- Riser/Tread Geometry:
- The ratio between treads and risers depends on the angle of the stair and the comfort range the designer wishes to achieve. The formulas used in various cities, states and countries vary. However, all agree that every step in a flight of stairs must be constant from the foot to the head and from landing to landing, with very little, if any, deviation or tolerance. It has been said that a stair should be built with skills of a fine cabinetmaker.
- The vertical part of a stair step; the height of each step from the upper surface of one step tread to the upper surface of the next step tread. All risers in every run of stairs including the platform and landing steps must be consistent from finished floor to finished floor. The optimum standards of deviation-tolerance for riser heights in a flight of stairs is plus or minus (±) 1/8th” inch. Builders and architects should practice construction standards that require a minimum of three stairs or greater for staircases or to design ramps and avoid the use of single stair and double step stairs which have been associated with many incidents.
- From the Anglo-Saxon verb, “stigan”, Middle English, from Old English “stæger” and meaning to climb or ascend. A step or a set of steps, or a run of steps enabling a person to ascend or descend from one level to another. A series of stepping-stones, shelves, or treads that enables a person to climb to a higher elevation or level with reduced effort.
- A set of stairs and its surrounding structure, walls, floors, ceiling and elements, etc.
- A single unit of a stair; the configuration of one riser and one tread to enable and accommodate, ascend or descend, floor or raised differential. (NOTE: See Riser. Single step units, where only one stair is used between platforms, must be avoided as they have been associated with many incidents.)
- Stringer or Carriage:
- The side or intermediate supporting structural members of a stair.
- The upper horizontal part of a step in a staircase; the stepping-foot-placement-shelf. Each tread of a stair must be of equal depth in every run of steps from platform to platform and from finished floor to finished floor from the foot of the stair to the head of the stair. Upper surface of all treads must have slip-resistant surface and must be true and level from front to back and from side to side, except exterior stairs where the tread can be slightly tilted down toward the nosing to permit drainage, known as the wash or kilt of a tread.
- Winding, Spiral, Circular or Helical Stair:
- Having the shape of a spiral or coil; a turning section of an entire staircase around an open atrium, turning wall, column or newel-post for decorative purposes or a spiral close section for utilitarian purposes. This type of stair, if not designed, built or maintained properly has been associated with many incidents due to the narrow treads or non-existent treads at the fulcrum.
- A spiral section of a staircase around a solid or open newel, wall, corner and usually at stair run corner, instead of a flat level platform. This design has been associated with many incidents. Many municipalities and code requirements do not permit them to be built.
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Stair & Ramp Safety - Technical Paper
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