BALUSTERS

BALUSTERS

Post 333 ⇒   by Gautam Shah 

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A baluster is a square or circular section shaft, traditionally made from wood or stone. Balusters are also made from hollow sections of metals, nowadays in extruded plastics or cast from cement concrete. Balusters are also called spindles, mid pickets, guards, or stair sticks.

Casa do raio Portugal

Balusters are used for forming a lattice in stair, gallery or terrace parapets. Full section and half section balusters are used as decorative elements on lower section of the wall and in furniture. Single baluster shafts, form a candlestick stand, column for supporting busts or stem of a chandelier.

Baluster

Balusters at the top edge are held by the coping or handrail of the parapet and at the bottom end by a runner base or are inserted into the step or floor. The entire assemblage of top rail, balusters and the bottom runner are known as the balustrade.

Baluster shapes -forms

The word Baluster =balaustra =pomegranate flower, derives from its shape resemblance to the swelling of a half-open pomegranate flower. Other words are balustre (French), balaustro (Italian), balaustium (Latin), balaustion (Greek). In India Balusters are also called Kumbhi or Lota (from Kumbha=pot).

Greek Amphora

Indian Lota or water pot

Many building codes require that opening within a parapet be of not more than 100 mm size. (There are three exceptions according to the 2003 International Building Code Section 1012.3, which allow openings not to exceed 200 or 500 mm, depending on occupancy groups or special areas.)

Chicago Cultural Center

The space between two balusters is equal to the width of the square base. A nominal tread width, may require two balusters. The second baluster in such cases is closer to the riser, and is taller than the first. This is done to maintain the mid bulge at the same level. It also allows the bottom part of decorative elements to be aligned with the tread, and the top elements are aligned with the railing angle. This, however, means the first and second balusters are not interchangeable and must be manufactured separately. Balusters without the horizontal decorative elements, with flutes or spirals patterns are interchangeable.

Gallery balustrade

Balusters have two basic configurations, top and bottom halves are mirrored forms, and other form has one elongated bulge with several rings at top and bottom. Other traditional baluster forms copy the Greek columns including the capital, or have fluted square column with a foliated capital. Stair and gallery balustrades need a proper turn around or ending. Balustrades could end to columns, building walls or more in a heavy newel post.

Baluster with bottom bulge

Double rows of balusters

The baluster, follow the wood turning styles and ceramic potters wheel shaping techniques. The form was copied in stone, metal, cement and plastic materials. Metals gave twisted fluting whereas plastics offered centre-less or off centric shapes.

Thin Sticks balusters

Balusters in Furniture

Assyrian palaces show window balusters in bas-relief. Balusters became very popular in Venetian buildings. The application to architecture was a feature of the early Renaissance. Giuliano da Sangallo has used balusters on the terrace at the Medici villa at Poggio a Caiano (1480 AD).

Verona Basilica di San Zeno Baluster in railing

Villa di poggio a caiano Balustrade Gallery

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RAILINGS AND PARAPETS

RAILINGS AND PARAPETS

Post 303⇒   by Gautam Shah  →

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Railings and Parapets are barricades against height related hazards. Railings and parapets both are important functional and architectonic elements. There are few characteristics and elements common to both. It is their nature of construction that places them in separate categories. Both are height-related hazards barriers, mainly for humans. Railings and parapets are invariably smaller than the human height, because most such elements are used for resting or grabbing with hands. For nominal usage 800-900 mm height is adequate, whereas difficult to negotiate (jump-over) conditions a height of 1400-1500 mm is considered. The later height is used for terraces of multi-story buildings to discourage suicides.

Patan Nepal

Design Parameters > Railings of nominal height ( 800-900mm) must have top 300mm as see-through face, so that children can see out. But if such a separation is likely to provide any toe space to climb up entire face should be see-through. All lattices should have preferably vertical bars and the clear gap must not exceed 100mm. For very tall railings (more than 900 mm) entire face must be of see-through elements and with a squared lattice. The squares in the lattice must not exceed 30 x 30 mm.

Parapets and Railings have sub elements such as: hand rail, Baluster or balustrade, banisters, volute, turn out, goose-neck, rosettes, easing, starting easing, over easing, core rail, newels, fillets, tandem caps, colonnettes.

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RAILINGS

Railings are translucent or latticed elements, placed at the edges of the floor and terraces. Railings are placed as safety barricade on the sides of stairs, ladders, ramps, and escalators. These are placed to demarcate zones, to segregate movement channels, to regulate queuing people, as barricade for animals, and to prevent crawling infants and children from moving into unprotected areas. Railings are placed near wells, tanks and other water bodies. Railings are placed on inclined or slippery floors to prevent slip-fall. Railings are placed in vast grounds for people or groups to anchor themselves.

Venice

Waverley Tram Depot Roof gable edge

The chief element of railings, are top rail, and secondary elements are posts that support the rail and latticed in-fill panels. A rail can be defined as any long member, usually of round section, fixed to posts, for resting hands, or for grabbing as a support. Railings have a top rail or hand rail used for holding, and a foot rail and mid rails. The hand rail in a masonry structure is a wider ‘table’.

Balusters

Masonry railings are often called parapets. In medieval castles, gapped parapets called crenellations or embrasures were formed to allow guns to fire through. On terraces and galleries of arid climates similar gaps are covered by pierced stones or metal lattice to allow the breeze to pass through at floor level of the terrace. This cooled the terraces faster, and provided comfort for occupants seating or sleeping on the floor. Latticed railing allows children to see through, and so discourage the climb-over.

Poole: wiggly barrier on the Twin Sails Bridge UK

PARAPETS

Parapets are opaque structures, often designed as an upward extension of the wall. Classical design of a parapet em-battlement of a coping at the top and corbel below. The top of the parapet often slopes towards the enemy to enable the defenders to shoot downwards, and this incline is called the superior talus. Parapets are placed at roof or terrace edges, or on embankments. Opaque parapets are used for deflecting winds, provide privacy to floor level activities, add weight to the edge to prevent lift-off forces. Parapets serve, besides defence-offence, other purposes, such as: to shield a view, as a noise barrier, barriers against splashes of storm-water, missiles or flying objects. Edge beams are designed as parapets. Parapets that are small in size are called curbs. Curbs are used as dividers.

Glass Parapet >Nottingham Castle Terrace

Essaouria Morocco

Fort walls have em-battlement parapets, which are pierced for styling, view beyond and for throwing defensive projectiles. Palaces and castles have decorative (non-defence) perforated parapets in various shapes such as circles, trefoils, quarter-foils.

The building act of 1707 in London and other towns of England banned the projected wooden eaves to prevent spread of fire along the wall, to the roof structure. A 18″ thick parapet was required and the roof edge was set back. The roof was set back little more to provide drainage of rain water. The parapet which was completely absent in earlier houses began to be treated by crenellation. (During medieval ages, provision of crenels required permission.) The parapet style was continued in Georgian houses giving an appearance of a flat edge roof. The parapets over the roofs were made taller, shaped, decorated and pierced.

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HAND RAILS

Post  –by Gautam Shah

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A hand rail is the topmost component of barricade systems like parapet or railing. Hand rails, without the barricading system, are provided in hotel lobbies, corridors, passages as a guide rail or an indicative element. The hand rail functions as guide rail as there no height related or other hazards are operative in such areas. As an indicative barrier it demarcates restricted areas. Such hand rails are not protective as a barricade but provide psychological support (assurance) for the hand or body. In this sense it has only a decorative function.

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A wall-mounted hand rail is used as gripping element, for travel along inclined or a slippery floor. Wall hand rails are required in toilets to change the posture. Hand rails are also provided on ships, sail boats and railway engines for holding in high winds and storms. Hand rails are heated or cooled by water or oil circulation depending on the external weather conditions. Top hand rails or hanging rails are used in buses and metro trains for commuters to remain stable in high speed conditions and against breaking forces. Top hand rails also have hangers for grabbing to meet varied anthropometric profiles of commuters. Hand rails are also used for guiding visually impaired persons in horizontal movement.

CityRail_hunter_railcar_handrail_at_door

A hand rail is the uppermost section of a barricade and so it is often used for resting against it, for placing hands, spreading elbows, or for gripping. Hand rails are provided with extra widths and higher height for supporting the elbow. For hand support and gripping appropriate sectional profiles are required.

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Standards for hand rail design are:

A handrail is defined as either a circular cross section with an outside diameter of 32 mm minimum and 50 mm maximum, or a non-circular cross section with a perimeter dimension of 100 mm minimum and 160 mm maximum, and a cross section dimension of 57 mm maximum. For a handrail with a perimeter dimension greater than 160 mm, a graspable finger recess area is to be provided on both sides of the profile. Handrails are located at a height between 860 mm and 960 mm. In areas where children use the facility, a second set of handrails at a maximum height of 710 mm (as measured from the ramp surface or stair nosing to the top of the gripping surface) is necessary. Sufficient vertical clearance between primary and secondary handrails should be minimum 230 mm to prevent entrapment of children. The distance between the wall and handrail is very important. Common requirements are between 38 and 57 mm.

A handrail on one side of a stairway is always necessary, (even where both sides are walls) and on both sides, if the stairway is more than 1000 mm wide. All stairways, balconies and certain other areas above ground level which are likely to be used for other than just maintenance, must also have a balustrade or guard. With a wide balustrade the actual or the effective width of a stair, balcony or passage is reduced. The clear unobstructed width between a wall face and the internal face of a balustrade or between two internal faces of handrails is considered as an allowable passage.

Rail for Adults and Children

Other Function of Hand Rail

A handrail serves many other functions, it often provides a lateral stability to the barricade system and joins pieces of barricade into a functional whole. Hand rails used for supporting the body may be designed to be non-continuous (for one or few persons), but hand rails used for horizontal movement such as in stairs, ramps, escalators, walkways etc. must be continuous. Continuous handrails are called: over-the-post and besides the post, and non-continuous handrails are called post-to-post and newel-to-newel.

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Positions or building elements that are likely to be unintentionally or abusively used as a hand rail, are designed or treated to prevent such a misuse. Some of the means used to discourage the usage are spikes, sharp knife edge profiles, sloped top face, or coating with non drying (green or ever-wet) paints. However, wider surfaces hand rails are provided to support planters and cut off the view of areas immediately close-below. Some handrails also have foot rails that are similar to Bar stools‘ foot rests.

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