Post -by Gautam Shah
Environment is a complex system. Its various aspects affect us differently. Some effects are concurrent and few are directional. Environmental barriers serving many different purposes are required.
Wind barricades are used for heavy wind sections as well as for the storm prone locations, such as sea fronts, valleys etc. These are designed to deflect the direction and diffuse the velocity of the winds. The barricades primarily depend on the quality of the terrain and man-made formations, such as sand dues, walls, screens, vegetation, walls etc. Projections like galleries, Chhajjas, screens, are also used for diverting the winds to the buildings. The flow is also diverted to specific interior areas of rooms by wind catcher ducts. Tropical houses have terrace parapets with a grill or lattice design to let the air pass through. Louvered doors and windows also control the air movement.
Water barricades are required against sea tides and ebbs, tsunamis, flooding, land washouts, snow and rain storms and eddy currents. These are in the form of vegetation, walls, dumps of modular or irregularly shaped cast units, landscaping and terrain contouring. Holland has devised variety of technological means against ingress of sea waters.
SUN SHADING BARRICADES
Sun shading barricades are shading devices, usually vertical or horizontal, and often in inclined positions. Locations above 23° N or South of the equator receive no sun rays from respectively North and South faces. All location under (within) 23° N or S of equator, however, receive some sun rays, and to curtail it sun shading devices of horizontal flat or inclined shape are required. For the same locations, on East and West faces, early part of morning and later part of the afternoons receive horizontal rays, but with Southern inclination. These require a dual shading consisting of horizontal and vertical (on the South side of the opening) elements. Sun shading devices such as Brise de soleil are used.
Radiation barricades are used against radiation sources, such as furnaces, open fires, oil wells and oil storage tank yards. Such barricades could be natural or man made. Natural radiation barricades are in the form of hills, contours, dunes, slopes, trees, hedges, foliage, plants, grass, climbers etc. Man-made radiation barricades are protection walls, embankments, ramparts, retaining walls and dykes.
NOISE CONTROL BARRICADES
These are created against super highways, railway tracks, airport runways, open mines, stone crushing plants and sites with pile drivers. The noise control barricades are made of dense vegetation, fibre boxes (grass), and hollowed or staggered construction. Stage podiums have parabolic overhangs to direct sound away from the stage and thus avoid the feedback in sound amplification system. Telephone booths in public spaces like malls, road sides, railway stations have specifically designed envelopes to prevent the background noise. Cinema and performance auditoriums are designed with optimum 1/4 to 1/3 audience occupation, as the bodies of audiences and their clothing absorb sound. Noise control barricades are in form of contoured planes to deflect and amplify the sound, low density surfaces treatments, baffles or cavities to absorb select frequencies of sound, or frequency generators to produce sound attenuation.