Perimeter protection

Perimeter protection using dikes, trenches, ditches, and clay cover... 

Controlling the movement of people within a facility is important but it is much better to stop intruders at the edge of a facility s property before they reach vital assets and operational areas. Perimeter protection includes such measures as ... 

Perimeter protection system A perimeter protection system places alarm sensors on all... 

A perimeter protection system places alarm sensors on all external doors and windows so that an intruder can be detected as he or she attempts to gain access to the protected property. 

Hollow core slab erection on the masonry wall requires installation of the perimeter protection where the masonry wall has to be constructed. This means the guardrail is installed then subsequently removed to continue the masonry construction. The erector will be exposed to a fall hazard for a longer period of time while installing and removing perimeter protection than while erecting the slabs. 

The support structure of the wheel depends on its size and diameter. For a smaller wheel, diameter typically below 150 cm, the core material itself is formed in the shape of a wheel and a round casing at its perimeter protects its edges. For a larger diameter wheel, the core material is manufactured into sections and is assembled into a spoke-and-rim structure, supported in a frame by a hub and bearing assembly in the middle (see Figure 8). 

Weak points in building perimeter protection that should be considered may include letter boxes, air vents and louvered windows. 

An intruder alarm system serves as a deterrent to a potential thief and often reduces home insurance premiums. In the event of a burglary they alert the occupants, neighbours and officials to a possible criminal act and generate fear and uncertainty in the mind of the intruder which encourages a more rapid departure. Intruder alarm systems can be broadly divided into three categories - those which give perimeter protection, space protection or trap protection. A system can comprise one or a mixture of all three categories. 

A movement or heat detector placed in a room will detect the presence of anyone entering or leaving that room. PIR detectors and ultrasonic detectors give space protection. Space protection does have the disadvantage of being triggered by domestic pets but it is simpler and, therefore, cheaper to install. Perimeter protection involves a much more extensive and, therefore, expensive installation, but is easier to live with. 

Step 3. Boron is ion implanted around the perimeter of the resist-protected area to form a "typ isolation border (the channel stopper or chanstop). The boron cannot penetrate through the resist. 

Extruded Rigid Foa.m. In addition to low temperature thermal insulation, foamed PSs are used for insulation against ambient temperatures in the form of perimeter insulation and insulation under floors and in walls and roofs. The upside-down roof system has been patented (256), in which foamed plastic such as Styrofoam (Dow) plastic foam is appHed above the tar-paper vapor seal, thereby protecting the tar paper from extreme thermal stresses that cause cracking. The foam is covered with gravel or some other wear-resistant topping (see Roofing materials). 

The security system can be considered as layers of protection. Physical barriers and deterrents constitute not only the building stmcture itself, made up of walls, doors, windows, floor and a roof, but the yard around the building and probably a perimeter fence or wall. 

An important principle is that security must be built in depth - otherwise known as defense in depth. In this context, it may be helpful to think of security as a set of concentric rings, where the target is located at the center. Each ring represents a level of physical protection (perimeter fence, building shell, security case) but the number of rings and security resistance will vary relative to the risk. The spaces between the rings may represent other defensive measures such as closed-circuit television (CCTV), security lighting, intruder alarm systems, etc. 

Fuel lines should be mn where they will not be subject to high temperatures and must include protection with automatic and manual shut-off fire valves at the perimeter of the boiler house. Individual boilers should also be capable of isolation from this supply. Local requirements may vary on fuel supply systems, and these should be ascertained before installation. 

Size of test site B Depends on study design. The minimum area required for a typical large-plot design is about 0.25 ha Test site must allow for test design plus sufficient buffer zone around perimeter of field to protect against external disturbance For bare-soil studies, shady sites should be avoided Continued overleaf)... 

High-permeability passive perimeter gas control systems entail the installation of highly permeable (relative to the surrounding soil) trenches or wells between the hazardous waste site and the area to be protected (Figure 16.6). The permeable material offers conditions more conductive to gas flow than the surrounding soil, and provides paths of flow to the points of release. High-permeability systems usually take the form of trenches or wells excavated outside the site, then backfilled with a highly permeable medium such as coarse crushed stone. 

Low-permeability passive perimeter gas control systems (Figure 16.7) effectively block gas flow into the areas of concern by using barriers (such as synthetic membranes or natural clays) between the contaminated site and the area to be protected. In the low-permeability system, gases are not collected and therefore cannot be conveyed to a point of controlled release or treatment. The low-permeability system can also alter the paths of convective flow. 

Magnetic switches (reed switches) The most widely used perimeter sensor. They are typically used to protect doors, as well as windows that can be opened (windows that cannot be opened are more typically protected by foil alarms). 

Free-standing sensors—These sensors, which include active infrared, passive infrared, bistatic microwave, monostatic microwave, dual-technology, and video motion detection (VMD) sensors, consist of individual sensor units or components that can be set up in a variety of configurations to meet a user s needs. They are installed aboveground, and depending on how they are oriented relative to each other, they can be used to establish a protected perimeter or a protected space. More details on each of these sensor types are provided below. 

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