COMPONENTS of RAILINGS
Post 412 ⇒ by Gautam Shah →
Railings are barricades against height related hazards, guides for pathways and grabbing elements for support while ascending, descending or any other physically difficult passage (such as slippery floors). Railings have a main holding or grabbing elements in the form of a continuous bar or rail, other in-fill components and support structures. The support structure is often designed as a spanning structural beam to reinforce the bridge, a waist of the stair or escalator. In very steel stairs such as ladders the sides of the stairs allow grabbing, and so are railing by themselves.
A railing is nominally a safety barricade used in a standing posture and so needs an optimum height provision. As a result the space between the passage and the railing requires some fill-up panel. This fill-up or in-fill could be of opaque, translucent to transparent material or a lattice. In stiff structures the in-fill could be of stiff construction, but rope bridges (catenary spans) need a flexible in-fill. Railings on roads are designed to take the impact of moving vehicles, and allow it to skid along it, but without an overturning. Railings in public places are designed to resist side thrust in case of pandemonium. Railings are designed with anti-ligature features to prevent suicides or unintentional injuries.
Railings are made of timbers, wood-composites, wrought iron, cast-iron, mild steel structurals or sections, stainless steels, plastics and composites, resin matrix composites, and masonry.
The components of the railing are identifiable in terms of their distinctive form, position and function. In some instances each of these has a perceptible presence, but it may not be a requirement of design. A proximate building element or an architectonic element may serve the functions of a railing. Railings, are bottom supported panel structures, wall supported linear elements, or suspended space entities.
Rail is the main grabbing and body support element of the railing system. This is a functional element which may not be the top member, but always at the optimum (for adults) height of 900 to 1200 mm. The rail may have an accompanying higher or lower barricading element. A rail could be an independent element of the other components of the railing. Rail can be a bar or an ergonomically conceived section or profiled top (cap-rail) of the in-fill panel or the barricade system. Rails are used with hand and so-called handrails, but a rail could support other parts or limbs of the body such as the buttock (metro trains and stations) or a foot (drink or snack bars). Informal rails are fabric or synthetic stripes that demarcate specific areas. Grab bars are placed in toilets, slippery or wet areas.
Support for Handrail: A handrail may be supported at end to end of flight of steps (usually negotiating 2 to 2.5 mts height) or may need intermediate supports called banisters.
A newel is a large picket or post that supports the handrail at the start and end or landing level. Newels are anchored to the floors or stair waists. Nominally the newel rests one step measure away from the last step. Newels may project upward then the rail level, and may be capped with an urn or finial. Volute is the end of a handrail, shaped like a spiral in a horizontal plane. A rail may not end as a free corner support of a newel, but may terminate into a wall or column as a rosette. A wall return is a bend that turns around a wall, column or a tall newel. Easement is the curved piece in the same plane or rising to form a turning transition of a rail. Similarly a goose-neck is a section between two differently sloped rail systems.
Rail sections carved out of wood are curved against the normal grain of the wood, such as for the volute, rosette, goose-neck or easements. These require additionally under the layer support of wood.
Baluster is a moulded shaft, square or circular, traditionally in stone, wood, metal, and now in plastics, supporting the coping of a parapet or the handrail of a staircase. The assembly is called the balustrade. Balusters are vertical mid pickets or members that hold the handrail. Sometimes these are simply called guards or spindles. Treads often require two balusters. The second baluster in such cases is closer to the riser and is taller than the first. A fillet is a decorative filler piece on the floor between balusters.