Stairs uniformity

Are step risers on stairs uniform from top to bottom ... 

These requirements to deck boards used as stair treads are much more severe compared to requirements to regular deck board, among them an ability to hold a uniformly distributed load of 100 Ib/fC multiplied by a safety factor of 2.5, hence, 250 Ib/fC. 

We have considered the above deflection of deck boards that serve as stair treads. Obviously, the same principle can be applied in the calculations of deflection of composite profiles in other cases deflection of soundwalls under force of wind (in this case an equation for uniformly distributed load should be applied), deflection of an animal farm fence under weight of an animal leaning toward a board, deflection of a deck board under a hot tub installed on the deck, deflection of a handrail under a cantilever force, and so on. 

There are several factors that affect stairs safety. They include uniformity of dimensions, resistance, slope, visibility, stmcrnral strength, width, tread depth, placement, and other feamres. 

Uniformity Stairs should have uniform dimensions for all steps in a flight. People walking up or down stairs intuitively establish measures of what stair dimensions are and expect the dimensions found in the first step to occur for the others. A sudden change in dimensions can cause stumbling similar to when a person misjudges the number of steps. 

Riser height and tread depth shall be uniform within each flight of stairs, including any foundation structure used as one or more treads of the stairs. Variations in riser height or tread depth shall not be over V4-inch (0.6 cm) in any stairway system. 

PGMs such as Pt and Pd (Figs 11.5 and 11.6). The membranes developed have been tested with various reactions, such as in proton exchange membrane (PEM) fuel cells and in hydrocarbon hydrogenation (e.g., Halonen et al, 2010 Job et al., 2009 Stair et al., 2006). The nanostructured membrane AAO framework studied by Stair et al. (2006) is presented in Fig. 11.6. A similar type of a framework has been used also with the CNT support framework (Kordas et al, 2006). This kind of a structure provides more uniform contact time and controlled reagent flow, as well as decreased sintering phenomena (Stair et al, 2006). By designing new catalyst systems by... 

Stair PC, Marshall C, Xiong G, Feng H, Pellin M J, Elam J W, Curtiss L, Iton L, Kung H, Kung M,Wang H-H (2006) Novel, uniform nanostructured catalytic membranes. Topics Catal, 39,181-186. 

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