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Joined: Jun 2005
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Originally Posted by Helena54
Never heard of billarks Leo, but I have heard of bollarks!!!!
you have spelt that wrong i am sure you mean
Bollard
The Retractable Bollard is a post (diameter 12 inches) made of concrete, stainless steel, aluminum, cast iron or other durable material, that creates an above ground obstacle, limiting vehicle access to a specific location that is reserved for pedestrians most of the time. This post can be lowered when passage is authorized, by any type of access control device (RF, card, key, etc.), or at any time in case of an emergency. When in the lowered position, the top is flush with the pavement or asphalt, and completely hidden.
Bollards can be operated manually, electrically, pneumatically, or hydraulically and respond to a wide range of security specifications and design requirements. For example, a basic unit is designed to provide dissuasive perimeter control and will shear off on an impact of up to 3000N, thereby limiting damage to the vehicle and the Bollard mechanism. At the high-end, Bollards are constructed to completely stop most vehicles; a “Defense” Bollard can withstand up to 300,000N and continue to operate (i.e. a truck traveling at high speed). Retractable Electrical Bollards can be raised (or lowered in 2-3 seconds), which means it is in the appropriate position virtually instantaneously.
Bollards are designed with numerous safety systems and can operate in the most severe conditions (temperature variations and precipitation). These features, along with high MTBF (1.5 million operations; for electrical bollards ) ratings, make Bollards an excellent choice for vehicle access control, satisfying requirements of both form and function.