What are protective barriers, and what should they entail?

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Chapter 5

Protective Barriers

Lawrence J. Fennelly, CPO, CSS, HLS III

Protective barriers are used to define the physical limits of an installation, activity, or area. Barriers

restrict, channel, or impede access and are fully integrated to form a continuous obstacle around the

installation. They are designed to deter the worst-case threat. The barriers should be focused on

providing assets with an acceptable level of protection against a threat.

Overview

Protective barriers form the perimeter of controlled, limited, and exclusion areas. Utility areas (such

as water sources, transformer banks, commercial power and fuel connections, heating and power

plants, or air conditioning units) may require these barriers for safety standards. Protective barriers

consist of two major categories: natural and structural.

• Natural protective barriers are mountains and deserts, cliffs and ditches, water obstacles, or other

terrain features that are difficult to traverse.

• Structural protective barriers are humanmade devices (such as fences, walls, floors, roofs, grills,

bars, roadblocks, signs, or other construction) used to restrict, channel, or impede access.

Barriers offer important benefits to a physical-security posture. They create a psychological

deterrent for anyone thinking of unauthorized entry. They may delay or even prevent passage through

them. This is especially true of barriers against forced entry and vehicles. Barriers have a direct

impact on the number of security posts needed and on the frequency of use for each post.

Barriers cannot be designed for all situations. Considerations for protective structural barriers

include the following:

• Weighing the cost of completely enclosing large tracts of land with significant structural barriers

against the threat and the cost of alternate security precautions (such as patrols, WMD teams,

ground sensors, electronic surveillance, and airborne sensors).

• Sizing a restricted area based on the degree of compartmentalization required and the area’s

complexity.

As a rule, size should be kept to a minimum consistent with operational efficiency. A restricted

area’s size may be driven by the likelihood of an aggressor’s use of certain tactics. For example,

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protecting assets from a vehicle bomb often calls for a substantial explosives standoff distance. In

these cases, mitigating the vehicle bomb would often be more important than minimizing the

restricted area to the extent necessary for operational efficiency.

Protective barriers should be established for the following:

• Controlling vehicular and pedestrian traffic flow

• Providing entry control points where ID can be checked

• Precluding visual compromise by unauthorized individuals

• Delaying forced entry

• Protecting individual assets

If a secured area requires a limited or exclusion area on a temporary or infrequent basis, it may not

be possible to use physical structural barriers. A temporary limited or exclusion area may be

established where the lack of proper physical barriers is compensated for by additional security posts,

patrols, and other security measures during the period of restriction. Temporary barriers (including

temporary fences, coiled concertina wire, and vehicles) may be used. Barriers are not the only

restrictive element, and they may not always be necessary. They may not be ideal when working with

limited or exclusion areas or when integrated with other controls.

Because barriers can be compromised through breaching (cutting a hole through a fence) or by

nature (berms eroded by the wind and rain), they should be inspected and maintained at least weekly.

Security-force personnel should look for deliberate breaches, holes in and under barriers, sand dunes

building up against barriers, and the proper functioning of locks.

Perimeter Entrances

Active perimeter entrances should be designated so that security forces maintain full control without

an unnecessary delay in traffic. This is accomplished by having sufficient entrances to accommodate

the peak flow of pedestrian and vehicular traffic and having adequate lighting for rapid and efficient

inspection. When gates are not operational during nonduty hours, they should be securely locked,

illuminated during hours of darkness, and inspected periodically by a roving patrol. Additionally,

warning signs should be used to warn drivers when gates are closed. Doors and windows on buildings

that form a part of the perimeter should be locked, lighted, and inspected.

Entry-Control Stations

Entry-control stations should be provided at main perimeter entrances where security personnel are

present. Considerations for construction and use should be based on the information outlined in

USACE STD 872-50-01.

Entry-control stations should be located as close as practical to the perimeter entrance to permit

personnel inside the station to maintain constant surveillance over the entrance and its approaches.

Additional considerations at entry-control stations include:Co py ri gh t @ 20 12 . Bu tt er wo rt h- He in em an n.

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• Establishing a holding area for unauthorized vehicles or those to be inspected further. A turnaround

area should be provided to keep from impeding other traffic.

• Establishing control measures such as displaying a decal on the window or having a specially

marked vehicle.

Entry-control stations that are manned 24 hours each day should have interior and exterior lighting,

interior heating (where appropriate), and a sufficient glassed area to afford adequate observation for

personnel inside. Where appropriate, entry-control stations should be designed for optimum personnel

ID and movement control. Each station should also include a telephone, a radio, and badge racks (if

required).

Signs should be erected to assist in controlling authorized entry, to deter unauthorized entry, and to

preclude accidental entry. Signs should be plainly displayed and be legible from any approach to the

perimeter from a reasonable distance. The size and coloring of a sign, its letters, and the interval of

posting must be appropriate to each situation.

Entry-control stations should be hardened against attacks according to the type of threat. The

methods of hardening may include:

• Reinforced concrete or masonry

• Steel plating

• Bullet-resistant glass

• Sandbags, two layers in depth

• Commercially fabricated, bullet-resistant building components or assemblies

Internal Barriers

Have you ever watched a trespasser come into a building? He walks slowly, he looks around, and his

eyes go right and left. He is 8 feet into your lobby and sees the turnstile and realizes he has been

denied access. So he proceeds to the security desk with a simple question of employment.

Barriers are psychological deterrents allowing unauthorized access. Turnstiles and access control

are physical barriers that control entry points and complement your security program and your

security officers.

Functions of structural and/or natural barriers include:

1. protection area boundaries.Define

2. —slow traffic or access. Consider speed bumps.Delay

3. access to garages, parking lots, and building entrances.Direct

4. unauthorized access and allow only authorized visitors.Deny

Designing Security and Layout of Site

Designing security into a new or renovated complex can begin with the exterior or interior. Since we

are discussing protective barriers in this chapter, let us assume we started the layout discussion on theC op yr ig ht @ 2 01 2. B ut te rw or th -H ei ne ma nn .

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outside.

Your main lines of defense are your perimeter barriers or the outer edge to your property line. The

second line of defense is the exterior of the building, which includes the roof and roof access and

walls, doors, and windows. Remember to eliminate all but essential doors and windows. If this is not

done in early stages, they will have to be alarmed and set up as emerging exits. Also included should

be adequate lighting (cost-effective) that meets standard and supports exterior closed-circuit TV

(CCTV). The third line of defense is the interior. It is important to reduce access points by using

access control and have specific areas zoned for access control and added security.

Passive Structural Barriers

• Jersey barriers

• Large boulders or rocks

• Large round cement stones

• Roadblocks or closed roads

• Fences

• Gates

• Bollards at entrances

Active Structural Barriers

• Hydraulic bollards

• Motor-operated lift-arm gates

• Pop-up wedges

• All geared to control traffic for entrances and exits

Barrier Planning

When planning a perimeter barrier, the following should be taken into account:

• Walls are usually more expensive than fences, observation enclosures, CCTV, and exterior lighting.

Opaque fences may provide a cheaper alternative.

• Fences and walls provide only limited delay against intruders; the least secure types can only delay

a skilled intruder for a few seconds. A perimeter barrier intended to provide substantial protection

against intruders should therefore combine a fence or wall with security lighting, an intruder

detection system, CCTV, and security guard forces.

• The perimeter should be as short as possible and illuminated.

• The perimeter should run in straight lines between corner posts to facilitate surveillance.

• Drains or culverts giving access beneath the perimeter barrier should be protected.

• The ground on both sides of the perimeter barrier should be cleared to deny cover to an intruder.

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• Emergency gates may be required to provide safe evacuation routes.

• A sterile zone protected by a double fence may be required for certain types of intruder detection

sensors.

• A security guard force should support the perimeter security system.

• Exterior emergency phones should be connected to the security officer’s desk.

• Barriers are deterrents. They come in a variety of acceptable sizes and shapes.

Fence Standards

The perimeter should have a fence or wall that meets the requirements of local planning and licensing

authorities while remaining an effective deterrent against intruders. As a guide, any fence less than 7

feet high is unlikely to do more than demarcate a boundary.

Generally, the basic perimeter fence should have concrete fence posts with three strands of

barbwire at the top. The barbwire should be at a 45-degree angle pointing upward and outward. The

foot-tall chain-link fences should be embedded in a concrete curb in the ground that slants away on

both sides from the fence to shed water and be buried deep enough to prevent burrowing.

Where local factors require an enhanced level of security, anti-intruder fencing is recommended to

a height of 7 feet with razor or barbwire at the top. The base of the fence should be embedded as

previously described.

Where the value of the protected side is particularly high and there is known risk (such as terrorist

attack), consideration should be given to augmenting the selected fence with security lighting, CCTV,

an intruder detection system, and a security guard force.

Types of Security Fences

The following fences are available for security use, and are listed in ascending order of their

effectiveness against intrusion:

• Industrial security chain-link fence.

• Standard anti-intruder chain-link fence.

• Standard steel palisade fence, security pattern standard expanded metal (Expamet) security fence.

• High-security steel palisade fence.

• Power fencing. This is similar to cattle fencing in that it will give an electric shock to anything

touching it. This type of fencing is generally safe to use around hydrocarbon sites, but the

manufacturer’s advice should be sought on its exact deployment. Power fencing sends an alarm

when touched, thus making it a barrier with intruder detection. It is also good to use above walls in

high-risk areas on domestic properties.

• Palisade fences are more expensive than chain-link fences but have better potential upgrading to

increase effectiveness against intruders and for the addition of fence-mounted intrusion detection

sensors. Galvanized palisade fences have a much longer life than chain-link fences, Expamet, orCo py ri gh t @ 20 12 . Bu tt er wo rt h- He in em an n.

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weld-mesh fences. The high-security fences are significantly more effective against intruders than

the other fences.

Summary

Keep in mind that structural barriers physically and psychologically deter and discourage the

undetermined, delay the determined, and channel the traffic flow through entrances.

References

1. FM 3-19.30, Field Manual Department of Army, Protective Barriers. 1979; Chapter 4, Section 4-1,

March 1.

2. Tyska L, Fennelly F. . Boston: Butterworth-Heinemann;Physical security—150 things you should know

2000.

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Chapter 6

Physical Barriers

Richard Gigliotti and Ronald Jason

When we speak of physical barriers, most people tend to think in terms of reinforced concrete walls,

chain-link fences topped with barbwire, modern bank vaults, and other such apparent applications of

maximum security. We can think back, however, to the Roman Empire, whose power and influence

extended over what was then almost all of the known world. The continuance of this power was

guaranteed by the establishment of outposts throughout the conquered territories controlled by

powerful Roman legions. These outposts were actually fortified garrisons—an example of using

physical barriers for protection of a base of operations.

This same principle has been used throughout recorded history: the British and Colonial fortresses

during the Revolutionary War, the U.S. Army forts in the Indian territories during the last half of the

nineteenth century, the French Maginot Line in World War II, and even the protected base camps

established by American forces in Vietnam. It is interesting to note that the last were actually a

variation of the system of forts used during the Revolutionary War to which forces could retire with a

relative degree of safety for rest and re-equipping.

The concept of physical barriers is not unique to . When a monkey climbs a tree, itHomo sapiens

takes advantage of a natural barrier in its environment, which provides a form of physical security.

While in the tree, it is out of danger from the carnivores that prowl the jungle floor, although not

completely safe from attack by other natural enemies.

People have used barriers to enhance physical security throughout history. Our earliest forebears

had the instinctive need for physical security in its most primitive form: the cave and the tree.

Certainly, the need for some edge in the game of survival was crucial to our continued existence. We

could not outrun the saber-toothed tiger and giant wolf, we had no protective shell like that of the

giant tortoise, we could not intimidate our enemies by sheer size like the mastodon, and our

reproductive capacity was limited. Only by using the security provided by climbing the nearest tree or

taking shelter in a handy cave were we allowed the necessary time to continue progress along the

evolutionary path.

As intelligence increased over the centuries, we understood that certain changes and improvements

could be made to the natural shelter available. There was not much to do to a tree, but by dragging

rocks, boulders, and fallen trees across the mouth of his cave, a person could erect rudimentary walls

and fences—physical barriers that enhanced the natural protection. The eventual addition of animal

skins to cover the openings in cave dwellings was another sign of the march toward civilization and

another component in developing physical security.

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