< Previous20 Section 2|Structural Considerations FLIGHTS AND LANDINGS This staircase in Manchester’s Central Library uses the same number of steps between numer- ous intermediate landings. Landings. Landings are often used to create a more interactive, social, and comfortable experience. For stair users with limited endurance, low stamina, arthritis, and loss of balance, among other conditions, landings provide essential frequent resting places. Landing Locations. Every stairway should have a landing at its top and bottom. Per the IBC, stairs that are higher than 12 feet tall require an intermediate landing in the middle of the stairway. Ten or Twelve Step Runs. The National Safety Council (NSC) recommends a landing be provided at every tenth or twelfth tread. Uniform Runs. Where stairs contain two or more successive flights, the number of steps in each flight or run should be the same where possible. Because the risk of falling on stairways is greater the longer the duration of exposure, staircase runs should not have too many steps without a landing. Ascending and descending stairways are daunting tasks for people with physical or mental limitations. A long continuous run of steps can contribute to fear of falling, which is associat- ed with frailty, reduced mobility, impaired gait and imbalance in older people. 21 universal design guidelines for feature stairs synergillc.com | 2022 Unobstructed Landings. Large landings, unobstructed by any door swings, should be provided at the top and bottom of each flight of stairs. The IBC requires that doors opening onto a landing not reduce the landing to less than one-half the required width. When fully open, the door cannot project more than 7 inches (178 mm) into a landing. Landings should be slip-resistant and free of projections. Shared Landings. Large landings, unobstructed by any door swings, should be provided at the top and bottom of each flight of stairs. Landings where elevators and stairs are shared should provide additional space. Where wheelchair spaces are required on the stairway landing, the IBC dictates dedicated wheelchair space, located outside of the required landing width. Any doors in the landing should not swing over wheelchair spaces. Landing Width. Landings should be the same width, measured perpen- dicularly to the direction of travel, as the stairway and extend at least three feet in length. Landing Depth. Landings are required to have a minimum depth, measured parallel to the direction of travel, equal to the width of the stairway or 48 inches (1219 mm), whichever is less.22 Level Connections. Because stairs are generally installed before the rest of the flooring surrounding them, it’s important to keep the intended floor height at the end of runs in mind. If the flooring at the top or bottom of a run is off by as little as 1 inch, the resulting height inconsistency can cause an accident. Staircase Width. The minimum code requirement for straight flight stair widths is 36 inches for areas with an occupant load of 50 or less and 44 inches for 50 or more people. However, a 69-inch stair width allows people to walk side-by-side in heavy clothing, with sufficient room between them for comfort and social distance. This is only a minimum recommendation; stairs should be wider still, to accommodate the varying speeds of people negotiating stairways. STAIRCASE DIMENSIONS People need adequate space on stairways to move safely and comfort- ably, including space for their body ellipse, pacing zone, senso- ry zone, and buffer zone. The clear width of internal stairs should be determined by the expected level of use.23 universal design guidelines for feature stairs synergillc.com | 2022 Cane Detection Railing. IBC requires areas with less than 80” of vertical clearance under stairs to be cane detectable. This is usually done with a barrier, such as cane detection railing. 27” is the maximum height for this barrier. A minimum height is not specified for this barrier, though it is recommended that barriers be high enough so that they are not mistaken for a step or other change in level and do not pose a tripping hazard. Clearance Around Structure. It is recommended that the area beneath an internal staircase is enclosed in order to avoid the potential for a person to collide with the soffit or any supporting elements. Where stairs are free-standing, any area where the clear height is less than 80 inches should be protected to prevent access. Headroom Clearance. Clear headroom of 86 inches minimum should be maintained throughout the full length of the stair flight and any landings. STAIRWAY ADJACENT AREAS From immodest views under- neath a staircase to clearance room for taller individuals, it’s important to consider the areas adjacent to a stairway that may cause discomfort or even pose potential safety risks for some stair users. 24 Section 2|Structural Considerations Assistance Waiting Area. Many people are unable to use stairs unassisted, such as young children, older people, or people with mobility difficulties. It is necessary to ensure that they can stay in a safe location until help arrives in case of evacuation. Stair design should include sufficient space at the top and bottom of stairs to accommodate these people without inter- rupting the travel of other stair users. Built-in seating under Synergi’s stairs in T- Mobile’s flagship San Francisco store not only prevents people from hitting their heads, it also provides ample area for users to await assistance while comfortably resting. 25 universal design guidelines for feature stairs synergillc.com | 2022 The seating both protects passersby from insufficient clearance space as they pass underneath the stairs and provides a com- fortable area to rest or gather. Obscuring Vantage Points. Efforts can be taken to repurpose the vantage point beneath a stair to reduce instances where passersby have a direct view of stair users. Open stairs should be positioned to minimize foot traffic beneath them, and natural obstacles such as fountains or potted plants can organically redirect walkers to points where they will not have a direct view beneath the stair.universal design guidelines for feature stairs 26 SECTION THREE Synergi’s stairs at the headquarters for the American Physical Therapy Association - the APTA Centennial Center - located in Alexandria, Virginia.27 synergillc.com The use of steeper slopes in order to fit the stairway in a building or to increase the economic efficiency of the building plan, i.e. more rentable or salable space, should be avoided. In ascent, high risers require a higher leg lift, which causes missteps. In descent, control of balance is more difficult as people shift their weight forward and downward for longer distances while balancing on one leg in each footfall. It is the users’ comfort and safety that should determine the slope of a stairway. Risers & Treads28 Section 3|Risers & Treads SLOPE : RISE & RUN The height of a stair’s riser and the depth of the tread, known collec- tively as the rise and run, determine the slope (or the steepness) of the staircase. The comfort and safety of those using a stairway, rather than its footprint, should determine its slope. Shallow and Steep Stairways. Stairways that are too shallow use large treads, forcing people to overextend their gait or to take each step with both feet, which results in an awkward walking rhythm. Conversely, steep stairways use treads that are too narrow to accommodate the length of the foot and increase the risk of overstepping. Slope of Walking Surfaces. The ADA’s Accessibility Guidelines for buildings (ADAAG) dictates that the walking surfaces of treads and landings (from side to side) cannot change in level and cannot have a slope greater than 1:48.29 universal design guidelines for feature stairs synergillc.com | 2022 Measuring Riser Height. Riser height is measured vertically between the nosings of adjacent treads. Riser Height. A riser height ranging between 4 and 7 inches is required by the building code for accessible stairways in public buildings. Measuring Tread Depth. Tread depths are measured horizontally between the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread’s nosing. Tread Depth. A tread depth of 11 inches at minimum is required by the building code for accessible stairways in public buildings. Slope. The slope of the stairway should allow comfortable walking gaits. A riser height ranging between 4 and 7 inches and an 11-inch tread depth minimum is required by the building code for accessible stairways in public buildings. Optimum Stairway Slope. In an analysis of 63,000 ascents and descents on a variety of stair- ways, a recent study found fewer incidents occurred on stairways with 7-inch vertical rises combined with 11-inch tread depths. Known as the 7-11 design rule for accessible stairs, findings determined this to be the optimum stair ratio to reduce the risk of falling.Next >