1. Perimeter Security Measures.
A. Perimeter protection is the first line of defense in providing physical security for a facility. This can be accomplished by installing fences or other physical barriers, outside lighting, lockable gates, intrusion detectors, or a guard force. Perimeter protection also includes walls, lockable doors and windows, bars and grills, and fire escapes.
B. In addition to defining the physical limits of a facility and controlling access, a perimeter barrier also creates a physical and psychological deterrent to unauthorized entry. It delays intrusion into an area, making the possibility of detection and apprehension more likely. It aids security forces in controlling access and assists in directing the flow of persons and vehicles through designated entrances.
C. Every vulnerable point should be protected to deter or prevent unauthorized access to the facility. The roof, basement, and walls of a building may contain vulnerable points of potential entry. A security survey of the perimeter should address manholes and tunnels, gates leading to the basement, elevator shafts, ventilation openings, skylights, and any opening 96 square inches or larger that is within 18 feet of the ground.
D. The extent of perimeter controls will be determined by the senior facility manager, based upon a comprehensive physical security survey (Appendix C). The survey report should recommend perimeter controls to the facility manager.
2. Physical Barriers. Physical barriers may be of two general types, natural and structural. Natural barriers include mountains, cliffs, canyons, rivers, or other terrain difficult to traverse. Structural barriers are man-made devices such as fences, walls, floors, roofs, grills, bars, or other structures that deter penetration. If a natural barrier forms one side or any part of the perimeter, it in itself should not automatically be considered an adequate perimeter barrier, since it may be overcome by a determined intruder. Structural barriers should be provided for that portion of the perimeter, if required.
3. Fencing. Fences are the most common perimeter barrier or control. Two types normally used are chain link and barbed wire. The choice is dependent primarily upon the degree of permanence of the facility and local ordinances. A perimeter fence should be continuous, be kept free of plant growth, and be maintained in good condition.
A. Chain Link. Chain link fencing should be laid out in straight lines to permit unhampered observation. It should be constructed of number 11 gauge or heavier wire mesh (two inch square) and should be not less than seven feet high and have a top guard. It should extend to within two inches of firm ground. It should be taunt and securely fastened to rigid metal posts set in concrete. Anti-erosion measures like surface priming may be necessary. Where the fence traverses culverts, troughs, or other openings larger than 96 square inches in area, the openings should be protected by fencing, iron grills, or other barriers to prevent passage of intruders. Chain link fencing is low in maintenance cost, a minimal safety hazard, and has openings small enough to discourage the passage of pilfered articles.
B. Barbed Wire. Standard barbed wire is twisted, double strand, number 12 gauge wire, with four-point barbs spaced four inches apart. Barbed wire fencing, including gates intended to prevent trespassing, should be no less than seven feet in height plus a top guard, tightly stretched, and should be firmly affixed to posts not more than six feet apart. Distances between strands should not exceed six inches.
C. Top Guard. A top guard is an overhang of barbed wire along the top of a fence, facing outward and upward at an angle of 45 degrees. Three or four strands of barbed wire spaced six inches apart are used, but the length of the supporting arms and the number of strands can be increased when required. The supporting arms should be affixed to the top of the fence posts and be of sufficient height to increase the overall height of the fence at least one foot. Where a building of less than three stories is used to form a part of the perimeter, a top guard should be used along the outside wall to deter access to the roof.
4. Gates.
A. The purpose of a gate is to provide a break in a perimeter fence or wall to allow entry. Gates are protected by locks, intermittent guard patrols, fixed guard posts, contact alarms, CCTV, or a combination of these. The number of gates and perimeter entrances should be limited to those absolutely necessary, but should be sufficient to accommodate the peak flow of pedestrian and vehicular traffic.
B. Gates should be adequately lighted. They should be locked when not manned and periodically inspected by a roving guard force. Utility openings in a fence that do not serve as gates should be locked, guarded, or otherwise protected.
C. Intrusion detection devices may be desirable when the gate is used intermittently or when a higher level of protection is desired. Alternatives to detection devices include coded card keys, push button combination locks, and CCTV.
5. Protective Lighting. Protective lighting is a valuable and inexpensive deterrent to crime. It improves visibility for checking badges and people at entrances, inspecting vehicles, preventing illegal entry, and detecting intruders both outside and inside buildings and grounds. Locate protective lighting where it will illuminate shadowed areas and be directed at probable routes of intrusion. Also, overlap lighting to prevent dark areas. If justified, include emergency power for lighting.
6. Doors.
A. A door is a vulnerable point of the security of any building. A door should be installed so the hinges are on the inside to preclude removal of the screws or the use of chisels or cutting devices. Pins in exterior hinges should be welded, flanged, or otherwise secured, or hinge dowels should be used to preclude the door's removal. The door should be metal or solid wood. Remember that locks, doors, doorframes, and accessory builder's hardware are inseparable when evaluating barrier value. Do not put a sturdy lock on a weak door. The best door is of little value if there are exposed removable hinge pins, breakable vision panels, or other weaknesses that would allow entry. Transoms should be sealed permanently or locked from the inside with a sturdy sliding bolt lock or other similar device or equipped with bars or grills.
B. Overhead roll doors not controlled or locked by electric power should be protected by slide bolts on the bottom bar. Chain link doors should be provided with an iron keeper and pin for securing the hand chain. The shaft on a crank operated door should be secured. A solid overhead, swinging, sliding, or accordion type garage door should be secured with a cylinder lock or padlock. Also, a metal slide bar, bolt, or crossbar should be provided on the inside. Metal accordion grate or grill-type doors should have a secured metal guide track at the top and bottom and be secured with a cylinder lock or padlock.
7. Windows.
A. Windows are another vulnerable point for gaining illegal access to a building. Windows should be secured on the inside using a lock, locking bolt, slide bar, or crossbar with a padlock. The window frame must be securely fastened to the building so that it cannot be pried loose. As with glass panels in a door, window glass can be broken or cut so the intruder can reach inside and release the lock.
B. Bars and steel grills can be used to protect a window. They should be at least one half inch in diameter, round, and spaced apart six inches on center. If a grill is used, the material should be number nine gauge two-inch square mesh. Outside hinges on a window should have non-removable pins. The hinge pins should be welded, flanged, or otherwise secured so they cannot be removed. Bars and grills must be securely fastened to the window frame so they cannot be pried loose.
8. Manholes, Grates, and Storm Drains. Many facilities have manholes and tunnels providing service entrance into buildings. Other manholes may provide entrance to tunnels containing pipes for heat, gas, water, and telephone. If a tunnel penetrates the interior of a building, the manhole cover should be secured. A chain or padlock can be used to secure a manhole. Steel grates and doors flush with the ground level may provide convenient access. These openings may be designed into the facility as they may provide light and ventilation to the basement levels. If the frame is properly secured, the grates or doors can be welded into place or they can be secured with a chain and padlock. Sewers or storm drains that might provide an entrance should be secured.
9. Roof Openings. Openings in elevators, penthouses, hatchways, or doors to the roof are often overlooked because of infrequent use. Access to a building’s roof can allow ingress to the building and access to air intakes and building Heating, Ventilating, and Air-Conditioning (HVAC) equipment (e.g., self-contained HVAC units, laboratory or bathroom exhausts) located on the roof. From a physical security perspective, roofs are like other entrances to the building and should be secured appropriately. Roofs with HVAC equipment should be treated like mechanical areas. Fencing or other barriers should restrict access from adjacent roofs. Access to roofs should be strictly controlled through keyed locks, keycards, or similar measures. Skylights are another source of entry from the roof. These openings can be protected like windows - with bars or mesh. Such protection should be installed inside the openings to make it more difficult to remove.
10. Mechanical Areas.
A. Prevent Public Access to Mechanical Areas. Mechanical areas may exist at one or more locations within a building. Some mechanical areas have access from the perimeter, other mechanical areas may only have access from the interior of a facility. These