Posted on January 29, 2019
Stainless Steel Bollard Covers – Visit Our Site Now To Identify Extra Suggestions..
Security Bollards and Post Covers
The aftermaths of the 1995 Oklahoma City bombing and the September 11, 2001, attacks saw a sharp rise in the installation of bollards for security purposes. Anti-ram installations include not just posts, but other objects made to resist impact without presenting the look of a protective barrier, such as large planters or benches that bollards. Once the design threat is determined the resistance necessary to stop it can be calculated. (See ‘Security Design Concepts’ – below). Specification of anti-ram perimeter takes into consideration both the mass as well as the speed of an approaching attack vehicle, with the latter being regarded the more significant.
In accordance with Weidlinger Associates principal, Peter DiMaggio – an expert in security design – careful assessment in the surrounding site is required. “Street and site architecture will determine the maximum possible approach speed,” he said. “If there are no approaches to the building having a long run-up, an attack vehicle cannot build up high-speed, and the resistance in the anti-ram barriers could be adjusted accordingly.”
Anti-ram resistance is often measured using a standard created by the Department of State, known as the K-rating. K-4, K-8 and K-12 each reference the ability to stop a truck of a specific weight and speed preventing penetration from the payload more than 1 m (3 ft) beyond the anti-ram barrier. Resistance depends not merely on the size and strength in the bollard itself, but additionally on the way it is actually anchored and also the substrate it’s anchored into.
Videos of bollard crash tests are featured on several manufacturer’s Internet sites. The truck impacts several bollards at high-speed, and the front of the vehicle often crumples, wrapping completely across the centermost post. Part of the cab may disappear the truck, the front or rear end could rise several feet in the air, and front or rear axles might detach. The bollards as well as their footings are sometimes lifted several feet upward. In all successful tests, the payload on the back in the truck will not penetrate a lot more than 1 meter past the line of bollards, thus satisfying the standard.
The easiest security bollard is a piece of 203-mm (8-in.), 254-mm (10-in.), or 305-mm (12 in.) carbon steel structural pipe. Some impact resistance is achieved even with a 102-mm (4-in.) pipe, depending on the engineering of its foundation. It is often filled with concrete to boost stiffness, although unfilled pipe with plate stiffeners inside may actually produce better resistance within the same diameter pipe. Without any kind of internal stiffening, the pipe’s wall-thickness has to be significantly greater. For fixed-type security bollards, simple pipe bollards could be functionally sufficient, if properly mounted. Undecorated pipe-type bollards can also be specially manufactured.
The largest drawback to a plain pipe is aesthetics. A bit of painted pipe fails to truly blend into – a lot less enhance – most architectural schemes. However, this is often overcome with a decorative bollard cover. Many standalone bollards which do not have impact-resistance of their own are created with alternative mounting ability to slip over standard pipe sizes, forming an attractive and architecturally appropriate impact-resistance system. These decorative covers can be available to enhance specifically created (but non-decorative) pipe-type bollards.
Security Design Concepts
Much of modern security design focuses on the threat of bomb attacks. The most significant aspect in protecting against explosions will be the distance involving the detonation and also the target. The force in the blast shockwave diminishes as being a purpose of the square in the distance. The more distance which can be placed involving the detonation and also the protected structure – known as standoff distance – the higher the threat resistance or, conversely, the less blast resistance must be built into the dwelling. Therefore, development of secure perimeter is the initial step within the overall form of blast resistance.
Standoff is valuable architecturally because it allows a building to become protected without needing to resemble a bunker. In addition, it has economic impact, because it is frequently less costly to produce standoff rather than bomb-proof the structure itself. Security bollards and similar anti-ram installations are designed and positioned to generate standoff by thwarting the delivery of explosives close to the target by a vehicle.
Any security design is dependent upon a bid of the size of threat to get resisted – the ‘design threat.’ The force from the explosion which can be expected is directly associated with the body weight- and volume-carrying capabilities from the delivery vehicle. Explosives are measured in relation to tonnes of trinitrotoluene (TNT). Probably the most potent molecular explosives such, as Composition 4 (i.e. C-4), are approximately one third stronger than TNT, whereas a fuel and fertilizer bomb – like was used in Oklahoma City – is considerably less powerful than TNT. Reasonable approximations can be produced regarding how much explosive power may be delivered by a person carrying a backpack, a passenger vehicle, a pickup truck, a flatbed truck, etc. according to the weight-and volume-carrying capacity.
You will find three basic varieties of bollard mountings: fixed, removable, and operable (retractable or fold-down). Fixed bollards could be mounted into existing concrete, or set up in new foundations. Manufactured bollards are frequently created with their very own mounting systems. Standalone mountings can be as non-invasive as drilling into existing concrete and anchoring with epoxy or concrete inserts. Such surface-mounted bollards can be used purely aesthetic installations and substantial visual deterrence and direction, but provide only minimal impact resistance.
Bollards designed to protect against impact are often baked into concrete several feet deep, if site conditions permit. Engineering from the mounting depends upon design threat, soil conditions and other site-specific factors. Strip footings that mount several bollards provide better resistance, spreading the impact load more than a wider area. For sites where deep excavation will not be desirable or possible (e.g. an urban location with a basement or subway under the pavement), pipe bollard covers created using shallow-depth installation systems are accessible for both individual posts and sets of bollards. Generally speaking, the shallower the mounting, the broader it must be to face up to impact loading.
A removable bollard typically features a permanently installed mount or sleeve below grade, as the sleeve’s top is flush with the pavement. The mating bollard could be manually lifted out from the mount to enable access. This etxxdy is supposed for locations in which the change of access is occasionally needed. It could add a locking mechanism, either exposed or concealed, to stop unauthorized removal. Both plain and decorative bollards are available for this kind of application. Most removable bollards are certainly not designed for high-impact resistance and therefore are not often utilized in anti-ram applications.
Retractable bollards telescope down below pavement level, and might be either manual or automatically operated. Manual systems sometimes have lift-assistance mechanisms to relieve and speed deployment. Automatic systems could be electric or hydraulic and often include a dedicated backup power installation so the bollard remains functional during emergencies. Retractable systems tend to be unornamented.
Bollards are as ubiquitous as they are overlooked. They talk to the need for defining space, one of the basic tasks in the built environment. Decorative bollards and bollard covers give you a versatile solution for bringing pleasing form to a number of functions. The range of available options is vast in terms of both visual style and gratification properties. For security applications, a design professional with security expertise should be included in the planning team.