Chapter 11
Physical Security
Abstract
In this chapter, barriers are both defined and discussed for students. Perimeter protection and locks/keys are explained with regard to their critical roles in ensuring security for an organization. The difference between safes and vaults is also discussed.
Keywords
Chain-link fence; Continuous lighting; Master key; Mechanical locks; Safes; VaultsBarriers can be divided into two types: natural and structural. Natural barriers are bodies of water, mountains, marshes, deserts, or other terrain that occur without man’s intervention. Structural barriers are walls, fences, grills, bars, or any other manmade structure.
Both types of barriers are used to:
1. Define property boundaries
2. Deter entry
3. Delay and impede unauthorized entry
4. Channel and restrict the flow of traffic
5. Provide for more efficient and effective use of security forces
Perimeter security
Perimeter protection refers to the use of barriers and manpower to surround and physically protect valuable material or information.
Great care should be taken to ensure that the structure to be protected receives maximum exposure. If possible, the structure should be placed in such a way that all four sides are visible. Also, landscaping precautions should be taken to be certain that large quantities of plants are not located within 50 feet the structure.
Fencing
Fencing is usually used to protect large areas. There are three basic types of fencing:
1. Chain link, which is used to secure permanent facilities
2. Barbed wire, which is used for less permanent facilities
3. Concertina wire, which is used in emergency or short-term situations
Chain-link fencing (Figure 11.1) should be straight as possible, and it is usually 8 feet in height. The fence should be erected 50 feet or more from the building or object to be protected. No. 11 gauge or heavier wire should be used. Mesh openings in the fence should be no larger than 4 square inches.
Barbed-wire fencing (Figure 11.2) is seldom used to protect a perimeter due to unsightliness and danger. It should be constructed of No. 12 gauge wire, twisted and barbed every 4 in. It should be at least 8 feet in height [1].
Concertina wire fencing (Figure 11.3) consists of barbed wire clipped together at intervals to form cylinders weighing approximately 55 pounds; it is sometimes referred to as “razor ribbon”. Sections of fence are 50 feet in length; one coil placed on another creates a fence of 6 feet in height. It can be laid quickly and easily retrieved; thus, it is good for emergency situations. However, it is difficult to cut.
Protective dogs
Protective dogs are used to provide either a physical or psychological barrier. The dogs are generally divided into two categories: sentry dogs and attack dogs. Sentry dogs (Figure 11.4) are usually kept on a short leash as they make the rounds with a security officer. They keep the handler alert, provide companionship, and give confidence. They are most effective at night.
Some problems may occur with the use of a sentry dog. Industrial noise will significantly interfere with hearing, and a strong order of oil will impair the dog’s sense of smell. In addition, dogs are not used extensively because security officers may not enjoy animals and/or may be incapable of handling sentry animals. To be effective, the security officer and sentry dog must spend a lengthy period of time training together, in addition to time spent caring for the animal (food, cleaning, etc.).
Guard or attack dogs (Figure 11.5) are different from sentry dogs. Guard dogs usually patrol inside fence areas and buildings without a human handler. Guard dogs will attack without command and are often used by car dealers, retail stores, scrap yards, and warehouses. The decision to use guard dogs must be evaluated with regard to the significant liability factor in the event the animal attacks.
Building service security
The second line of defense is the actual building, which consists of six sides: a roof (very vulnerable), a floor, and four walls [2].
Windows
In addition to the roof, windows are extremely vulnerable to forced entry. Glass windows can be reinforced with metal bars or grates placed on the outside of the windows. Window alarms, such as foil, were once widely used to protect windows. Window foil (which is similar to aluminum foil) is usually 3/8 to 1 in. width and is taped onto the inside portion of a window. An electric current passes through the foil in a nonalarm status. The foil forms a continuous electrical current. If the foil is torn or broken, thereby causing a disruption in the electrical current, an alarm is sounded. Typically, liquor and jewelry stores used window foil alarms on large storefront windows, but now most have converted glass breakage and/or microwave sensors that detect movement. Glass breakage alarms can be discretely placed inside of a window. With vibration alarms, an alarm will sound if the window is jolted. A glass breakage alarm sounds once glass in the window is broken or cracked.
Because windows are commonly used in residential and industrial settings, it is important to have at least a basic understanding of how glass is made and how windows are secured so that they remain in place.
Window glass is usually installed in one of three ways:
1. Putty
2. Molding, which may be nailed to the window
3. Window frames, such that the glass can be inserted in the grooves and then clamped into place with a glazing compound
Glass can be reinforced to minimize damage. Plastic can be adhered to glass to resist shattering.
Tempered glass is treated to resist breakage by placing a piece of regular glass in an oven, bringing it almost to its melting point, and then chilling it rapidly. A skin forms around the glass, which strengthens the glass to three to five times its normal strength. Tempered glass is also more resistant to heat.
Laminated glass (used in street-level windows and display glass) is made of two sheets of ordinary glass, which are bonded to an intervening layer of resilient plastic material. Laminated glass, which is about 5/16 in. in thickness, is shatter resistant.
“Bulletproof glass” is actually bullet resistant. It is constructed of laminated glass and plastic. Bullet-resistant glass is 3/4 to 3 in. thick.
Wired glass was used in the past by many institutions, particularly schools, but it is generally considered to have limited acceptability. Wire is inserted between two sheets of glass during processing; when the glass dries, the wire is secure. Plastic glass, such as acrylic glass, is much lighter than regular glass. Generally, plastic glass is more expensive, but it is easier to install because of its lightness [3].
Doors
Special precautions need to be considered when installing doors to ensure that the door and/or frame cannot be easily removed to allow for unauthorized entry. Close attention must be paid to fire codes, especially the Life Safety Code, which usually requires all doors to open outward. Doors can be alarmed to allow for exit, but local fire codes must be reviewed before exit doors are locked. In the 1990s, the time-delayed panic door release was developed. This device requires a person who is exiting to hold the handle down for 15 seconds before the latch is released and the door is opened. The purpose of the delayed release is to allow for a reasonable level of security while ensuring safety controls are met. While the door handle is held down, a camera can record the identity of the person trying to exit.
Security lighting
Security or protective lighting serves as a deterrent for potential criminal activity. A study of six areas in California by the National Criminal Justice Information and Statistics Services shows that in 69% of the burglaries studied, the point of entry was not illuminated [1].
Today, the smallest communities provide for street lighting in their budgets. As protective lighting has developed, it has come to serve many functions. The National Evaluation Program on Street Lighting Projects outlined the varied uses:
Lighting basically serves three purposes:
1. Advertises the owner or facilities manager’s product or service during the evening hours
2. Assists in pedestrian and vehicle traffic
3. Deters unauthorized entries and exits from the facility and may aid in the apprehension of assailants
Planning for an effective protective lighting layout must take into consideration the following:
1. Size: Larger objects require less light than smaller objects. Larger objects reflect more light.
2. Brightness: Light color reflects more light than dark color. A building that is painted white will need less lighting than one that is painted a dark color. Brightness is a level of light.
3. Contrast: Coarsely textured objects tend to absorb light, whereas smooth surfaced objects tend to reflect light.
4. Time: Greater illumination is required when areas are visually complex or crowded.
Lighting terminology
Candle power: One candle power is the amount of light emitted by one standard candle. The standard has been established by the National Bureau of Standards and is commonly used to rate various systems.
Foot candle: One foot candle equals one lumen of light per square foot of space. The density or intensity of illumination is measured in foot candles (the more intense the light, the higher the foot candle rating for the light).
Lumen: One lumen is the amount of light required to light an area of one square foot to one candle power. Most lamps are rated in lumens.
Brightness: Brightness refers to the ratio of illumination to that which is being observed. High brightness on certain backgrounds makes observation difficult. Brightness, therefore, should not be too low or too high relative to the field of vision [1].
As an example, the sun on a clear day supplies about 10,000 foot candles of light on earth. It is generally accepted that 100,000 foot candles of light is the upper tolerance limit for light striking the human eye.
Lighting can provide a psychological deterrent to convince a would-be attacker that penetration attempts would likely lead to detection and/or apprehension. A simple, nonscientific manner to measure whether lighting is adequate in a parking area is to see if a newspaper could easily be read. Alternatively, if tossing a baseball back and forth with a friend, would you be able to easily see the flight of the ball?
Many years ago the author had accepted a security management position with a Cleveland, Ohio based company. One evening as he was walking to his car in the employee parking lot, he was surprised by the low lighting in the area. After some discussion with the maintenance manager, they inquired with the local electrical company, who agreed to upgrade the lighting for a nominal fee. High-pressure sodium floodlights were added, and the immediate and overwhelming positive impact from the employees was very gratifying! A lighting survey was not conducted nor was a lighting professional consulted. Rather, a common-sense approach was initiated and action was taken that improved the overall opinion of employees on their safety.
Types of protective lighting
Continuous lighting is most common type of lighting. With continuous lighting, a series of fixed lights are installed so that a protected area is flooded with overlapping cones of light.
A second type of lighting is glare protection, which is often used in illuminating the perimeter of a facility. Lighting with floodlights is a form of glare protection. Floodlights (Figure 11.6) can be mounted on poles, roof lines, or on top of a building’s walls or fence. High-pressure sodium floodlights have become very popular. The high-pressure sodium lights emit an orange light that provides for greater illumination than the mercury-vapor light, which emits a blue light. In addition, high-pressure sodium lights use less energy than mercury-vapor lights. A 400-W high-pressure sodium floodlight produces illumination equal to a 1000-W mercury-vapor floodlight. Many electric utility companies provide a service that allows their customers to convert from the mercury-vapor lights to high-pressure sodium for a nominal charge.
A third type of lighting is controlled lighting. As the name implies, this type of lighting is designed to light a particular area in a controlled fashion. It is generally used to light facilities and areas that cannot use glare protection lighting. Parking lot lighting used by most hospitals and colleges is an example of controlled lighting. Controlled lighting allows for sufficient illumination but does not cause glare that could prove dangerous to motorists.
Finally, lighting can be supplemented with movable lighting and emergency lighting systems. Movable lighting became extremely popular for use in college football games in the 1990s. Many football stadiums in the early 1990s did not have permanent lighting, but television networks induced many colleges and universities to move their Saturday afternoon games to the late afternoon or evening hours in order to televise the games during prime time. Large banks of light were transported on moveable cranes or “booms” and were elevated above the stadium. These movable lights provided illumination similar to the fixed lighting systems.
In summary, when a lighting system is being constructed, security needs, safety concerns, and cost must all be addressed.
Locks and keys
Locks and keys have existed in a variety of forms for centuries. This discussion will focus primarily on four types of locking systems:
1. Mechanical
2. Electro-mechanical
3. Electronic
4. Combination
Mechanical locks
Mechanical locks use a barrier arrangement of physical parts to prevent the opening of the bolt or latch.
The three functional assemblies are:
1. The bolt or latch, which actually holds the movable part (door, window, etc.)
2. The tumbler array, which is a barrier that must be passed to move the bolt
3. The key or unlocking device, which is specifically designed to pass the barrier and move the bolt
Types of mechanical locks include the following:
• A warded lock is the lock that has been in use longest, being developed in the first century B.C. It is easily vulnerable, and the key is not resistant to weathering. Homes built in the early 1900s may have warded locks (skeleton-type design).
• A lever lock was developed in the eighteenth century. It offers greater security than the warded lock. Keys can be cut to different dimensions to operate the lock, which is known as master keying. It is still used in cabinet and locker installations and bank safe deposit boxes. Although it is susceptible to picking, precautions during lock design and manufacturing can reduce this to a low level.
• A pin tumbler lock was an important development in the nineteenth century by Linus Yale. It is now the most widely used lock in the United States; the maze/obstacle segment is different from other locks.
• A conventional tumbler always has its pins equally spaced in one row only.
• The plug rotates the key when properly inserted and permits the bolt to be drawn or “thrown” by rotary action.
• The shell is the immovable housing where the plug is fitted. The pin tumblers extend from the shell into the plug, thereby preventing the plug from turning.
• A wafer tumbler lock uses wafers (flat metal discs) to bind the plug to the shell.
• A common use of keys and locks for convenience and ease of operation is master keying. Master keying refers to the ability of one key or set of keys to unlock more than one lock. Although master keying affords convenience, three problems occur as a result:
• Proper accountability of master keys must be maintained.
• A lock is easier to manipulate because of the ability of different keys to unlock it.
• Maintenance of the system is increased because of the additional keys.
Electro-mechanical locks
Electro-mechanical locks operate either entirely through electrical energy or with an electrical release feature as an adjunct to any standard mechanical lock. Usually, electro-mechanical locks use 115 V of AC power. In an effort to make these types of locks more secure, the lock is enclosed in a metal container, which is physically resistive to outside energy sources and will not release the bolt unless the exact electrical energy level is received.
Electronic locks
Electronic locks require certain combinations or sequences of events to occur before the control circuit will deliver electrical energy to the mechanical or latch release. Locks of this type include card key systems.
Combination locks
Dial combination locks operate by aligning gates on tumblers to allow insertion of a fence on the bolt. These locks offer better security but are more expensive. Most combination locks are manufactured with two to six tumblers, each with a slot or notch cut into its edge. When all these notches are aligned by the proper turning of the dial, an arm (fence) drops into a slot created by the alignment and the locking bar can be retracted from the strike to open the lock.
Key systems
A key is the standard method of allowing entry through a locked door as well as relocking the door. Most key locks are designed to accept only one key, which has been made and cut to fit the lock. Keys and keying systems are generally divided as follows:
1. Change key: Standard key that fits a single lock within a master key system or any other single lock unnumbered by such a system. Numerous locks can be “keyed alike” to accept only one key.
2. Maison key: Type of submaster very common in apartment houses and office buildings. This key unlocks an apartment and the main entrance door.
3. Master key system: By splitting the bottom pin into two or more segments, two different cuts or combinations of different keys will raise the bottom pins to the shearline, which allows for unlocking.
4. Submaster: Opens all locks of a particular area or grouping within a facility.
5. Master key: Opens all locks in the facility that are part of the master key system.
6. Grand master: Opens every lock in a key system involving two or more master keys.
7. Control key: Maintenance key that removes the core from the housing and allows for recombinating the lock; useful when keys are lost.
Key control
Key control is vital if an effective lock and key system is to exist. It is generally recommended that a person who has security responsibility (of some sort) be designated as the key control person. This individual would issue all keys, note changes in personnel who possess keys, review all requests for new keys, and conduct regular inventories to ensure all keys are properly accounted for. An electronic log is maintained (using a computer software program) for all keys and lock transactions. Grand master keys should not be routinely issued. Instead, they should be securely stored for use in an emergency. Likewise, master key issuance should be restricted. A loss of a master key compromises all of the locks which were part of the master or submaster system. All keys should be identified by coding or marking along with a notation that the key is not to be duplicated.
Types of lock bolts and latches include the following:
• Deadbolt: A deadbolt does not contain a spring and it must be manually moved into the strike by turning a key or thumb turn. Deadbolts provide a greater degree of security, but fire codes must be reviewed to ensure that proper precautions are taken before the installation of a deadbolt lock.
• Spring-loaded latch: A spring-loaded latch provides a minimum level of security because the latch can be withdrawn from the strike whenever force is applied to the latch itself.
• Spring-loaded deadbolt latch: A spring-loaded deadbolt latch operates in the same manner as the spring-loaded latch, except an extra latch (bar) is located on the side of the latchbolt.
In summary, locks and keys provide only a reasonable level of security. If an attacker desires entry, a good lock and key system will only delay the assault; however, this delay is important and may serve as a deterrent if the attacker feels that he or she may be observed. Naturally, the benefits of a lock and key system are enhanced if careful planning is undertaken during the installation of the system and proper key controls are in place and enforced.
Nearly 50% of all illegal entries occur by the intruder entering through a door. A basic lock and key system that is utilized to its fullest extent can reduce the illegal entries.
Safes
A labeling service is provided by Underwriters Laboratories (UL) and the Safe Manufacturers’ National Association (SMNA), which defines the level of protection each safe can be expected to provide.
Record safes and fire protection
Paper is destroyed at 350 °F, whereas electronic data records (computer storage media) can be destroyed at 150 °F. It is necessary that moisture be built into the insulation of the safe to help remove heat during a fire. As long as there is sufficient moisture to displace the heat, the contents will be protected. Moisture cannot be replaced in the insulation of a safe that has been in a previous fire. For this reason, a safe that has been exposed to a fire, even if it does not show signs of damage on its surface, should be replaced.
Labels on safes that describe their fire-resistive characteristics can usually be found on the back of the safe’s door or in the interior of the safe.
An example of the UL and SMNA ratings is shown below:
| SMNA Designation | UL Designation |
| A | 350 °F—4 h |
| B | 350 °F—2 h |
| C | 350 °F—1 h |
All three classes are given three tests: fire exposure, explosion, and impact. Insulated file safes designated as class D or E provide far less protection from both fire and impact. For example, if a safe is rated Class A by SMNA and 350 °F—4 h by UL, it would withstand temperatures up to 2000 °F for 4 h. During this 4-h timeframe, the temperature of the interior of the safe would not exceed 350 °F, which would allow this safe to protect documents. Class C safes are the most popular and commonly used safes.
Electronic data processing record protection
Because electronic data processing (EDP) records begin to deteriorate at 150 °F and at humidity levels of more than 85%, these records are often protected by using a safe within a safe. This is done with a container that has a sealed inner insulated repository in which the EDP material is stored, and an outer safe protected by a heavy wall of insulation.
Safes designed to protect money
Safes that are designed to protect money or other forms of negotiable (such as checks) differ greatly from fire-resistant safes. Because fire-resistant safes contain a great deal of insulation to protect the safe’s contents from heat, these safes are more susceptible to burglary and robbery.
Robbery-resistive safes will prevent thefts when there is no actual assault on the safe itself. Chests with key locks, lockers, and wall safes with either key or combination locks fit this category. Robbery-resistive products require steel bodies and doors of less thickness than is required for burglary-resistive safes. Robbery-resistive safes afford a satisfactory level of security in protecting money and other valuables provided force is not used to open the safe. Remember that robbery involves the taking or attempt of taking something of value from a person by force, the threat of force, and/or violence. Robbery-resistive safes provide only some protection against robbery.
Burglary-resistive safes differ greatly from robbery-resistive safes. Burglary-resistive safes will resist attack by tools, torch, or explosives in direct proportion to their construction. These safes are constructed of reinforced or solid steel. Remember that burglary is the unlawful entry of a building to commit a felony or theft. Burglary differs from robbery in that most cases the burglar is attempting to steal from another person without their knowledge, such as a person breaking into a business after closing to steal from a safe. When a robbery is committed, the victim knows immediately of their loss because they are being forced by the assailant to give up their property.
The Insurance Services Office classifies safes. Examples of some of these classes are described below:
| Class | Doors | Walls |
| B | Steel-less | Body of steel (fire resistive) less than 1 in. thick or iron less than 1/2 in. thick; any iron or steel safe having a slot through which money can be deposited. |
| C | Steel at least 1 in. thick | Body of steel (burglar resistive) at least 1/2 in. thick; safe bearing label “UL inspected keylocked safe KL burglary” |
| E | Steel at least 1½ in. thick | Body of steel (burglar resistive) at least 1 in. thick |
Vaults
Vaults differ from safes in that vaults are larger and are part of the building structure. Vaults should have walls of 12-in. reinforced concrete, steel doors, and a combination lock.
Summary
• Physical security consists of barriers that are either manmade or natural. Natural barriers are bodies of water, mountains, marshes, deserts, and other terrain. Barriers define property boundaries and provide for better use of security forces.
• Perimeter protection consists of fencing, protective dogs, buildings, windows, doors, and lighting.
• Locks and keys are essential in any type of security program. Locks can be mechanical, electro-mechanical, electronic, or a combination type. The warded lock has been used longer than any other lock. The lever lock provides better security than warded locks. Lever locks are still used in cabinets and lockers. The pin tumbler lock was developed in the nineteenth century and is the most widely used lock in the United States. It is important that proper records of locks and keys are maintained. Deadbolts are a good security device used in many locks. Deadbolts must be physically moved with a key or thumb turn and are difficult to force open.
• Safes are usually designed to protect valuables from fire or burglary. The Underwriters Laboratory and the Safe Manufacturers National Association both test and label safes to describe their level of protection. Safes are designed to protect computer records and money or other valuables. Safes may be robbery resistive or burglary resistive.
• Vaults differ from safes. Vaults are larger and are part of the building. They should have walls of 12-in. reinforced concrete, steel doors, and a combination lock. Vaults usually provide a higher degree of protection than safes.
Exercises
1. Name three types of fences and how they are used.
2. What purposes does proper lighting provide?
3. Describe master keying.
4. What are the duties and importance of a “key control” person?
5. What are the differences in fire-resistant versus burglary-resistant safes?
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