Post 570 –by Gautam Shah
Barriers are obstructing and intervening entities. Barriers through their configuration, position and occurrence affect things passing by, touching, or going through them. Barriers rarely operate on their own, so are distinguished by the context or the surroundings where they operate. Barriers operate as multi functional entity doing many intended and unintended things.
Physical barriers are omnipresent in structure and effect. But non-physical barriers could occur through sensory variations. A subtle shift in texture, gradient, colour, illumination level, view, temperature, audio perception changes the behaviour of the user and can become an effective barrier.
Visual barricades use colours in terms of their brightness and other optical qualities such as fluorescence, reflection and background-foreground contrasting. Visual barricades also include use of illumination or brightness, blinking (dynamic) lights, iridescence.
Barricades Consuming Energy bar or control the exchange between the two faces. Barricades, themselves are variously affected by the exchange occurring through them. Some barricading systems use energy, to cause specific changes during the exchange process and also to revert to the nominal status. Barricading systems capable of using energy are machines, or some live beings, if additionally can reproduce or self sustain.
Protective barricades are designed to resist the most unfavourable combination of imposed loads (impact, wind, etc.). Such barricades allow planned deflection and distortion, with or without a collapse. A noncollapsible barricade is resilient enough to revert to the original position, whereas the collapsible barricade at a predetermined stage becomes ineffective. These conditions are included through a structural configuration, material technologies and through machine devices (operating on feed forward and feed back).
Soft Barricades recover after an impact, but do not bounce-back the striking object. Rubber flaps or plastic stripes on warehouses doors are flexible barriers.
Hard Barricades are used to divert (bounce back) the force of the impact. On express highways the shape and height of the railings and curbs are so designed that a vehicle on striking slides along it rather than thrown-back into the fast-moving traffic.
Transparent, Translucent Or Opaque Barriers: A glass barricade could be transparent for light but not for other objects. A large aperture grill could be ‘transparent’ for light, air and view, ‘translucent’ for an infant, pet etc., but ‘opaque’ for a fat man. A vertical or horizontal Venetian blind could be ‘transparent’ or ‘translucent’ from a particular position and could be ‘opaque’ from another position. A smoke glass is ‘opaque’ for view from outside but ‘transparent’ for view from inside. Fast-moving air in an ‘air curtain system’ is a transparent barricade.
Notional Barricades are used for ceremonial purposes or as a representative form of a barricade. A wrought iron chain, a rope around a monument, podium, dais or rostrum, a red ribbons for inauguration, yellow tape of police investigation teams, are all notional barricades. Similarly signs and symbols (danger, do not enter, slow, stop) can also be used for barricading. If the users are knowledgeable, and are ready to accept a set social behavioural norm, than indicative barricades (non physical) are as effective as physical barricades. However, it should be possible for the user to recognize, feel and experience the presence of such barricades. Where such opportunities for recognition are not available, non physical barricades fail to be effective. Notional barricades are not recognized in a crowded area or in a chaotic situation. Similarly where barricades are required as protection against unknown elements, notional barriers are not effective.
Barricades are required at all places of hazards such as: construction sites (for the safety of workers, visitors, and trespassers), works in public areas (such as trenches, excavations), place near electrical equipments (with exposed parts that could be live, and installations with voltage of over 440 volts), any area where explosives are used or stored, to define the radius of any cranes or such equipments, etc. Barricades serve as warning (through visual and other sensorial recognition) and also as a protective element. Barricades also denote territories, ownership and right of ways.