Components of Physical Security

In physical security, there is no one measure that can fulfill all security needs for any one facility. Therefore, security measures must be designed in layers. According to Lawrence Fennelly "physical security is the most fundamental aspect of protection, it is the use of physical controls to protect the premises, site, facility, building, or other physical asset" (2004). The many components or layers of security measures are what make up good physical security. The assets being protected and the nature of the threat to the asset will dictate the amount of physical security used to protect it "for any security countermeasure to be effective, the threat has to be clear."(Pepper 2010) Whether you are protecting warehouse goods or special nuclear material, layering security controls is the key to good physical security and protecting the asset.

The outer perimeter for a facility or business will depend on where it is located and the type of facility it is. For an office, building in a downtown environment the outer perimeter would be the outer wall of the building. If the facility is more spread out, for example, a chemical production plant, the outer perimeter is usually marked with a wall or fence on the property line, but the outer perimeter could also be a natural barrier as well, like a lake or river.

Fences are the most common type of barrier used today. Fences can vary in size and how they are used, which in return affect the effectiveness and level of protection. A fence can be used in many different ways. It can be used as a barrier to restrict access to an area, and keep unauthorized persons out, or it could be used merely as a delay barrier design to slow an attacker or adversary down allowing responding security force members time to take actions to defend the facility.

Being reasonable in cost and reasonable easy to setup, the most common type of fence is the chain link fence. Unlike walls and other types of fences, chain link fences also give a clear view of both sides of the area. Enhancements can also be made to a fence to make it more effective. Razor wire or barbed wire can be attached to the top of the fence, making it more complicated for an intruder to climb over. Alarm systems can also be attached to a fence. Any fence used as a perimeter barrier should be at least seven feet high or high enough it could not be easily scaled. A fence should also be close enough to the ground as to leave a gap big enough for an intruder to crawl underneath it. Fences should also be checked on a regular basis for damage to the fence fabric and washouts underneath it.

Walls can also be constructed on the outer perimeter to form the first layer of physical security. Walls can be harder to penetrate than a fence, and you would not have to worry about washouts or intruders going underneath a wall. However, walls can cost more than a fence; also, visibility in the perimeter area is lowered. With a wall, you cannot see the other side without some kind of assistance. Like with a fence, a wall can be enhanced with razor or barbed wire to make scaling the wall more difficult. When the wall of a building is used as the outer perimeter than that changes things. Intruder climbing the wall are no longer looking to get to the other side, but intruders are looking to gaining access to the roof. In addition, monitoring and controlling access at all building openings becomes critical.

The outer perimeter can also have a vehicle barrier as well. Vehicle barrier system may be necessary for facilities that run a high risk of a vehicle attack of some sort, for example, a nuclear power plant. Vehicle barriers can be integrated into the perimeter fence or further inward, wherever it would be more effective, the different types of vehicle barriers are; aircraft cable, blocks, walls, and natural barriers like ditches. Most nuclear facilities have good examples of vehicle barriers in place. Most nuclear facilities must protect against a vehicle carrying a set amount of explosives. Therefore, a vehicle barrier system must be a part of their physical security to protect the facility.

Natural barriers can also be effective as perimeter barriers. Natural barriers are natural land marks used as a perimeter barrier, such as lakes, rivers, cliffs, and difficult terrain. The effectiveness of a natural barrier depends on the type of natural barrier it is, and how it is used in physical security measures. Therefore, Lawrence Fennelly offers this example to explain how the type and usage of a natural barrier can affect the effectiveness of the barrier, "a body of water may be very effective in keeping pedestrian traffic away from your property but not very effective at keeping boat traffic from your property" (2008). Man-made barriers can also be placed to enhance the natural barrier, like in the example a wall or fence can be placed in the area to keep boat traffic away from the property. Just like man-made barriers, natural barriers can also be overcome, therefore they should be monitored at all times.

The facility grounds between the perimeter and the assets being protected can also be used as part of the physical security of that facility. These areas can be very effective as buffer zones if kept cleared, and monitored. Buffer zones can also be very effective for facilities that have to protect against forced entry by armed adversaries. These buffer zones create open areas that adversaries must cross to reach their objective. By moving into open areas, the security force will have a better chance of neutralizing the adversaries before any objectives are reached and the assets or integrity of the facility is jeopardized.

Lighting can be very effective when used right to enhance the physical security of facilities. According to P. Rosenberg "You should design protective or security-lighting systems on a facility-by-facility basis. There is not a one-size-fits-all approach. Each situation requires careful study to provide the best visibility, prevention of illegal entry and detection of intruders. You should not use protective lighting as a psychological deterrent only."(2000)When adequate lighting is used, likely intruders are less likely to enter the area in fear of being seen. Also with adequate lighting, all areas around the perimeter and inside the perimeter can be easily observed. Lighting should always be placed inside of the perimeter and be placed high enough to prevent tampering, and if tampering is done it would be deliberate in nature. Also all lighting should be protected in some way to prevent damage or destruction of the lights. All lighting used as physical security should be connected to some kind of backup power supply to prevent losing the lights in an event where the main power is lost.

Just like in the case of all other physical security measures, lights must be checked