MIL_HDBK_1013_10.pdf

INCH-POUND

MIL-HDBK-1013/10

14 MAY 1993

SUPERSEDING

See para 1.2

MILITARY HANDBOOK

DESIGN GUIDELINES FOR SECURITY

FENCING, GATES, BARRIERS, AND GUARD FACILITIES

AMSC N/A AREA FACR

DISTRIBUTION STATEMENT A.

UNLIMITED.

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION IS

ABSTRACT

This military handbook, MIL-HDBK-1013/10, provides the latest state-of-the-art criteria for security fencing, gates, barriers, and guard facilities and is primarily intended for use by Naval Facilities Engineering Command (NAVFACENGCOM) design engineers and architectural and engineering firms. The contents cover specific criteria to be used during the selection, design, and construction of security fencing, gates, barriers, and guard facilities.

ii

FOREWORD

This military handbook has been developed from an evaluation of security requirements contained in Department of the Navy and DOD directives, surveys of new materials and construction methods, evaluation and selection of the best design practices of Naval Facilities Engineering Command (NAVFAC), other Government agencies, and the private sector. It uses national, professional, and other society, association, and institute standards to the maximum extent feasible. Any deviations from the criteria contained in this handbook for the planning, engineering, and design of physical security fencing, gates, barriers, and/or guard facilities for Navy shore facilities shall not be made without prior approval of NAVFACENGCOM headquarters (Code 04).

Design of security fencing, gates, barriers, and guard facilities does not remain static any more than the functions they serve or the technology they use. As such, recommendations for improvement of this handbook are encouraged from within the Navy, other Government agencies, and the private sector.

Recommendations should be furnished on DD Form 1426 (provided inside the back cover) to the Naval Civil Engineering Laboratory (NCEL), Code L30, 560 Laboratory Drive, Port Hueneme, CA 93043-4328, telephone DSN 551-5743, (805) 982-5743.

THIS HANDBOOK SHALL NOT BE USED AS A REFERENCE DOCUMENT FOR PROCUREMENT OF

FACILITIES CONSTRUCTION. IT IS TO BE USED IN THE PURCHASE OF FACILITIES

ENGINEERING STUDIES AND DESIGN (FINAL PLANS, SPECIFICATIONS, OR ESTIMATES).

DO NOT REFERENCE IT IN MILITARY OR FEDERAL SPECIFICATIONS OR OTHER PROCUREMENT

DOCUMENTS.

iii

Criteria Manuals

MIL-HDBK-1013/1

DM-13.02

MIL-HDBK-1013/4

MIL-HDBK-1013/5

MIL-HDBK-1013/7

MIL-HDBK-1013/8

MIL-HDBK-1013/10

PHYSICAL SECURITY CRITERIA MANUALS

Title

Design Guidelines for Physical Security of Fixed Land-Based Facilities

Commercial Intrusion Detection Systems (IDS)

Instruction for Design, Fabrication and Construction/Installation of Secure Enclosures

Steel-Ply Wall Hardening Selection and Installation Guide

Security Hardware Installation, Operation and Maintenance

Combination Locks

Design Guidelines for Security Fencing, Gates, Barriers, and Guard Facilities iv

Preparing Activity

NCEL

LANTDIV

NCEL

NCEL

NCEL

NCEL

NCEL

Section 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9

Section 2 2.1 2.2 2.2.1 2.3 2.3.1 2.3.2 2.3.3 2.3.4 2.3.5 2.3.5.1 2.3.5.2 2.3.5.3 2.3.5.4 2.3.5.5 2.3.6 2.3.6.1 2.3.6.2 2.3.6.3 2.3.6.4 2.3.6.5 2.3.6.6 2.3.7 2.3.8 2.3.9 2.4

2.4.1 2.4.2 2.4.3

MIL-HDBK-1013/10

DESIGN GUIDELINES FOR SECURITY FENCING, GATES,

BARRIERS, AND GUARD FACILITIES

CONTENTS

INTRODUCTION

Scope Cancellation Criteria Documentation Application Technical Approach for Fence Design NATO Criteria Preliminary Physical Security Considerations . . .

Fencing Modifications Cost of Security

FENCES

Application Related Criteria Initial Barrier Design Chain-Link Fences Posts and Bracing Chain-link Fence Fabric Outriggers Accessories Erection Requirements Fence Placement Posts, Top Rails, and Bracing Chain-Link Fence Fabric Mounting Outriggers Accessories Special Security Features Clear Zones Patrol Roads Signs Drainage Culverts and Utility Openings Drainage Crossings Tunneling Maintenance Considerations Erosion Control Grounding Special Requirements for Fences Equipped with Intrusion Detection Systems (IDS) Sensors Taut-Wire Fences Special Requirements IDS Funding

Page v

Page

Section 2.5 Penetration-Resistant Barriers

2.5.1 Reinforcement of Perimeter Chain-Link Fence . . .

2.5.2 Additional Barriers

Section 3 3.1 3.2 3.3 3.4 3.4.1 3.4.1.1 3.4.1.2 3.4.1.2.1 3.4.1.2.2 3.4.1.2.3 3.4.1.2.4 3.4.2 3.4.3 3.4.4 3.4.4.1 3.4.4.1.1 3.4.4.1.2 3.4.4.1.3 3.5 3.6 3.7 3.7.1 3.7.2

Section 4 4.1 4.2 4.3 4.3.1 4.3.2 4.3.2.1 4.3.2.2 4.3.2.3 4.3.2.4 4.3.2.5 4.3.2.6 4.3.2.7 4.3.2.8 4.3.3

GATES

Application Related Criteria Types of Gates Design Selection of Gate Type Personnel Gates Vehicle Gates Sliding Gates Overhead Gates Swing Gates Vertical Lift Gates Hinges Locking System Gate Power-Operators Gate Power-Operator Design Sliding Gate Power-Operators Swing Gate Power-Operators Gate Power-Operator Peripherals Number and Location of Gates Traffic Control Penetration-Resistant Barriers Reinforcement of Swing Gates Reinforcement of Sliding and Vertical Lift Gates .

GUARD FACILITIES

Application Related Criteria Sentry Booths and Gatehouses Location Site-Built Structures Structure Size Windows Floors Construction Environmental Control Lighting Grounding Fortification Prefabricated Structures vi

Section 4.4 4.4.1 4.4.2 4.4.2.1 4.4.2.2 4.4.2.3 4.4.2.4 4.4.2.5 4.4.2.6 4.4.2.7 4.4.2.8 4.4.3 4.4.4

APPENDIX A Manufacturers

Figure 1

Guard Towers Location and Height Site-Built Structures Structure Size Windows Construction Environmental Control Lighting Grounding Fortifications Stairs and Ladders Prefabricated Structures Ballistic-Resistant Materials Data

APPENDIX

FIGURES

Fabric and Wire Fastener, Power Driven Steel Culvert Grill Concrete Culvert Grill Removable Grating for Culverts Large Culvert with Short Honeycomb Pipes Swale Crossing With Ground Stakes Swale Crossing Embedded in Concrete Bar Grill embedded in Concrete Chain-Link Fence Embedded in Concrete Sill . . .

Steel Cable-Reinforced Chain-Link Fence Deadman Anchor Single Swing Gate Double Swing Gate Single Cantilevered Gate Double Cantilevered Gate Single Wheel-Supported (V-groove) Sliding Gate . .

Single Overhead Supported Gate Double Overhead Supported (Biparting) Gate Turnstile (Rotational) Gate Entry Control Point Layout Nuclear Weapons Storage Site Entry Control Facility

Chain and Wire Rope Reinforced Gate Wire Rope Interwoven at Gate Post Chain and Wire Rope Locking System Wire Rope Clamps vii

Figure 26

Table 1

REFERENCES

GLOSSARY

Hydraulically Swaged Wire Rope Fitting Cable Reinforcement for a Sliding Gate Cable Reinforcement of a Vertical Lift Gate Chain and Wire Rope Reinforcing Sliding Gate Chain and Wire Rope Reinforcing Sliding Gate - Continued Chain and Wire Rope Reinforcing a Vertical Lift Gate Site-Built Sentry Booth/Gatehouse Floor Plan . . .

Typical Prefabricated Sentry Booth Guard Tower Designed by Sandia National

Laboratories Basic Components of a Chain-Link Fence

TABLES

Gate Post Foundations viii

Section 1: INTRODUCTION

1.1 Scope. This military handbook provides guidance and detailed criteria for the design, selection, and installation of new security fencing, gates, barriers, and guard facilities for perimeter boundaries of Navy and Marine Corps installations or separate activities, and designated restricted areas. Primarily, the criteria herein is based on the following Chief of Naval Operations Instructions (OPNAVINSTs):

a) OPNAVINST 5530.13A, Department of the Navy Physical Security Instruction for Conventional Arms, Ammunition, and Explosives (AA&E).

b) OPNAVINST 5530.14B, Department of the Navy Physical Security and Loss Prevention.

c) OPNAVINST C8126.1, Navy Nuclear Weapon Security Manual.

1.2 Cancellation. This military handbook, MIL-HDBK-1013/10, supersedes the following portions of NAVFAC Design Manual (DM) 5.12, Fencing, Gates and Guard Towers, dated October 1979: Section 1, paragraph 3; Section 2, paragraphs 2c and 3a; Section 3, paragraphs 1(1) and 1(d); portions of Table 1, dealing with Applications-Security, Perimeter, Nuclear Weapons; and, Table 2 in its entirety.

1.3 Criteria Documentation. Where criteria documentation such as Federal Specifications, Military Specifications, Naval Facilities Engineering Command (NAVFACENGCOM) Guide Specifications, etc., are cited, the latest version should be used for design.

1.4 Application. Physical barriers will be established around all perimeter boundaries and designated restricted areas as defined in Chapter 3 of OPNAVINST 5530.14B, Chapter 5 of OPNAVINST 5530.13A, and Chapter 3 of

OPNAVINST C8126.1.

1.5 Technical Approach for Fence Design. This handbook was developed to lead the designer through the detailed criteria required to establish a physical barrier around any Navy and Marine Corps perimeter boundary and designated restricted area. Perimeter boundaries and restricted area fence and barrier criteria from OPNAVINST 5530.14B have been used in this handbook as a baseline to design security fences. Where different or special requirements for AA&E or nuclear restricted areas are specified in OPNAVINST 5530.13A or OPNAVINST C8126.1, they are contained herein under the appropriate subject title and section.

1.6 NATO Criteria. There are differences between the criteria contained in this handbook and the criteria authorized or directed by the North Atlantic Treaty Organization (NATO). While this handbook may be used as a baseline for design of security fencing, gates, barriers, and guard facilities in Europe, obtain and follow specific NATO criteria to assure that specified NATO security requirements are met when designing these security components.

1.7 Preliminary Physical Security Considerations. Security fences will not stop a determined intruder. To be effective, such barriers must be augmented by security force personnel and other means of protection, detection, delay, and assessment. Security fences are used primarily to:

a) define the perimeter of a restricted area.

b) provide a physical and psychological deterrent to entry while serving notice that entry is not freely permitted.

c) prevent accidental entry.

d) optimize security force operations.

e) enhance detection and apprehension of intruders.

f) channel and control the flow of personnel and vehicles through designated portals.

Keep these factors in mind while proceeding with the security fence design.

Prior to making decisions to employ security fencing, perform a thorough risk and threat analysis to determine the degree of physical security required. As indicated in Chapter 2 of Chief of Naval Operations Instruction (OPNAVINST) 5530.14B, extensive and costly security measures may be justified in certain cases to protect certain assets of security interest; however, ultimately the commanding officer of an activity is responsible for complying with established security requirements while at the same time working to achieve economy. To achieve this objective, higher echelon security requirements must be clearly understood. Additionally, evaluate the relative criticality and vulnerability of the security interest in relation to a ranking of potential threats, and calculate the specific level of security to ensure the best possible protection for that threat level in a cost-effective manner. Only after the above preliminary factors are addressed can a proper design be initiated. See MIL-HDBK-1013/1, Design Guidelines for Physical Security of Fixed Land-Based Facilities, for guidance and more detailed procedures which may be helpful in the decision process.

It is imperative that security fencing requirements for restricted areas be evaluated on a case-by-case basis. Installing large quantities of security fencing around an entire outer perimeter may not be practical or cost-effective, and may not improve security, particularly in remote and unpopulated areas. Consider the following:

a) If the outer perimeter of the installation has adequate security fencing, then fencing of inner zones may not be required.

b) If the outer perimeter of the installation has barbed wire or hog-wire fencing or no fencing, security fences for inner facilities or storage areas may be more practical and cost-effective.

c) If the outer perimeter of the installation is partially fenced with a security fence, it may be more cost-effective to provide security fencing for the remainder of the outer perimeter rather than install security fencing around inner restricted areas.

d) If natural barriers such as mountains, cliffs, rivers, seas, or other difficult-to-traverse terrain form portions of the perimeter, then security fencing of the inner restricted areas may be more practical and cost-effective than providing security fencing either along or through these difficult-to-traverse areas.

In some cases, a request for a permanent exception to fencing requirements submitted in accordance with OPNAVINST 5530.14B may be more appropriate than erecting costly security fencing.

1.8 Fencing Modifications. Existing serviceable 6-foot (1.8-meter (m)) chain link fences (without outriggers) and gates constructed under the old version of OPNAVINST 5530.13A requirements do not need to be modified or replaced to meet the new OPNAVINST 5530.13A, 7-foot (2.1-m) (without outrigger) requirement.

Increasing the height of chain-link fencing by 1 or 2 feet (0.30 or 0.61 m) may, at best, increase the time to penetrate by going over the fence by only a couple of seconds. However, it has no effect on the time to penetrate the fence by cutting.

1.9 Cost of Security. Generally, physical security cost expenditures should be based upon the cost of the item to be protected, possible damage that the loss of the item could inflict upon the civilian population, and the importance of the item to the overall security and readiness posture of the command. The cost of security is frequently greater than the dollar value of the property or material protected. Sensitive items that may be a threat to the civilian population or vital to national security will be provided additional protection commensurate with their sensitivity and the threat to their loss or destruction.

Section 2: FENCES

2.1 Application. Requirements for security fencing generally fall into three categories:

a) General security and loss prevention.

b) Category I and II conventional arms, ammunition, and explosives (AA&E). (Security fencing will not be provided for Category III and IV AA&E storage facilities unless it is determined necessary based on an assessment of local threats, vulnerabilities, and cost-effectiveness.)

c) Nuclear weapons.

General design requirements for these security categories are contained in associated OPNAVINSTs. OPNAVINST 5530.14B provides requirements for general physical security and loss prevention, OPNAVINST 5530.13A provides special requirements for the protection of conventional AA&E, and OPNAVINST C8126.1 and NAVFACINST 11012.134A cover special requirements for nuclear weapons.

2.2 Related Criteria. The perimeter boundaries of all Navy and Marine Corps installations or separate activities will be either fenced or walled, and posted to establish a legal boundary. This defines the perimeter, provides a buffer zone, facilitates control, and makes accidental intrusion unlikely. It is important that consultation be made with local authorities to ensure that posting of barriers in areas of concurrent or proprietary jurisdiction complies with local or state trespass laws.

Establish a protective perimeter around all designated restricted areas. The protective perimeter will be a chain-link fence, taut-wire fence, the exterior walls of a structure, or a combination thereof. OPNAVINSTs state that when walls are used as a barrier, they will provide penetration resistance equivalent to, or greater than, the fence. In general, even security fences provide only seconds of penetration resistance. Stud and girt walls are the least penetration resistant of normal wall construction and will provide at least 1 minute of penetration resistance against a low threat level attack using limited hand tools. Therefore, most structure walls will provide equivalent or greater penetration resistance to fences.

Determine the type of barrier to be used after a study of local conditions and applicable directives. The barrier or combination of barriers used must afford equal and continuous protection along the entire perimeter of the restricted area. When a section of natural or structural barriers (or lack thereof) provide a lesser degree of protection, other supplementary means to detect and assess intrusion attempts must be provided or a waiver or exception requested.

Mesh openings will not be covered, blocked, or laced with material which would prevent a clear view of personnel, vehicles, or material in outer perimeter zones or areas. In those instances where the commanding officer determines obscuration to be more advantageous for protecting assets within the fenced area, a request for waiver or exception must be submitted. See

OPNAVINST 5530.14B.

2.2.1 Initial Barrier Design. When developing the design of security fencing, gates, barriers, and guard facilities, begin with the general design requirements contained in the appropriate OPNAVINST for the type of restricted area involved. Make an on-site inspection of the facility and area involved in the design. During the on-site inspection and during subsequent review, consider:

a) What types of walls or fences are present, their condition, and their adequacy to meet the design requirements specified in this handbook.

b) Proximity of protected area to public property.

c) Location and isolation of storage facilities.

d) Sensitivity of protected materials, mission, and personnel.

e) How the newly designed security barrier will best integrate with the existing surroundings.

f) Operational requirements.

g) The desirability or requirement for Intrusion Detection System (IDS) sensors along the perimeter, or the need for Close Circuit Television (CCTV).

h) The extent of local criminal activity and the protected area's vulnerability to that activity.

i) What, if any, local building codes or ordinances regulate construction or upgrades of the perimeter barrier system contemplated.

j) Any legal requirement to define the boundary of the protected area.

k) The need to make an engineering analysis to determine the stability of the soil.

l) Environmental conditions.

m) Safety and fire protection regulations.

2.3 Chain-Link Fences. Chain-link fencing is the type of structural barrier most commonly used to enclose restricted areas where fencing is required. Fabricate new and replacement fencing enclosing designated restricted areas, exterior to structures, with chain-link components. While chain-link fences are expensive, they require very little maintenance and provide little concealment for intruders. In evaluating the requirements for a perimeter fence, the security planner should remember that many perimeter barriers provide less than 10 seconds of delay time. The construction of a chain-link fence will not only define the protected area and cause an intruder to make an overt action that will demonstrate his intent, but will also provide a structure for installing IDS fence sensors to detect intruders.

Another advantage of fence systems is that they provide some explosives and ballistics standoff protection for making the perpetrator breech the fence line to reduce the distance to his target.

Federal Specification RR-F-191 is the primary criteria document for security fence components; however, do not specify aluminum fabric, poles, or accessories for security fence components. Definitions for fence components are provided in American Society for Testing Materials (ASTM) F 552, Definitions of Terms Relating to Chain-Link Fencing, and in the glossary of this handbook.

Take particular attention in areas with harsh environments to determine if Type IV chain-link fabric (which provides a plastic coating over zinc-coated steel) material is desirable. ASTM A 90, Standard Test Method for Weight of Coating on Zinc-Coated Galvanized Iron or Steel Articles, or ASTM A 428, Standard Test Method for Weight of Coating on Aluminum-Coated Iron or Steel Articles may be used to assure adequate protection for chain-link fence components. Use ASTM standards where supplemental criteria is either required or desired.

2.3.1 Posts and Bracing. Ensure all posts for security fencing meet the requirements of Federal Specification RR-F-191/3 for one of the following classes:

a) Class 1 - Steel pipe.

b) Class 3 - Formed steel sections.

c) Class 4 - Steel H-sections.

d) Class 6 - Steel square sections.

Accomplish bracing with steel truss rods not less than 5/16-inch (7.9-millimeters (mm)) nominal diameter and a turnbuckle for tensioning, conforming to RR-F-191/4.

Use the following ASTM Standards to supplement RR-F-191/3 and RR- F-191/4:

a) ASTM A 120, Specification for Pipe, Steel, Black and Hot- Dipped Zinc-Coated (Galvanized) Welded and Seamless, for Ordinary Uses.

b) ASTM F 626, Standard Specification for Fence Fittings (particularly evaluation of corrosion resistance and material compatibility).

c) ASTM F 669, Specification for Strength Requirements of Metal Posts and Rails for Industrial Chain-Link Fence.

d) ASTM F 1083, Specification for Pipe, Steel, Hot-Dipped Zinc- Coated (Galvanized) Welded, for Fence Structures.

2.3.2 Chain-Link Fence Fabric. Ensure chain-link fence fabric meets the requirements of RR-F-191/1 for one of the following:

a) Type I - Zinc-coated steel.

b) Type II - Aluminum-coated steel.

c) Type IV - Polyvinyl Chloride (PVC) coated over zinc- or aluminum-coated steel.

Security fences will be fabricated with 9-gauge (3.9-mm) steel wire mesh material (before any coating) with mesh openings not larger than 2 inches (50.8 mm) per side. Ensure the fabric height is 7 feet (2.1 m) and has twisted and barbed selvage at the top and bottom.

The designer may use the following ASTM Standards to supplement RR-F-191/1 for chain-link fabric:

a) ASTM A 116, Specification for Zinc-Coated (Galvanized) Steel Woven Wire Fence Fabric.

b) ASTM A 392, Specification for Zinc-Coated Steel Chain-Link Fence Fabric.

c) ASTM A 491, Specification for Aluminum-Coated Steel Chain- Link Fence Fabric.

d) ASTM A 817, Standard Specification for Metallic-Coated Steel Wire for Chain-Link Fence Fabric.

f) ASTM F 668, Standard Specification for Poly Vinyl Chloride (PVC)-Coated Steel Chain-Link Fence Fabric.

2.3.3 Outriggers. Single arm steel barbed wire support arms

(outriggers) are required for all station perimeter fences. When specified by the local command, they also may be added to interior restricted area security fences for additional deterrence. Double arm steel barbed wire support arms are required for nuclear storage areas. Ensure outriggers and barbed wire conform to the requirements of RR-F-191/4. Use ASTM A 121, Standard Specification for Zinc-Coated (Galvanized) Steel Barbed Wire, or ASTM A 585, Standard Specification for Aluminum-Coated Steel Barbed Wire, to supplement

RR-F-191/4.

2.3.4 Accessories. Ensure accessories such as steel fittings and components used in the erection of chain-link fences meet the requirements of RR-F-191/4. Use ASTM F 626 to supplement RR-F-191/4. Provide fittings electrolytically compatible with connecting fittings, components, and the fence fabric to inhibit corrosion.

2.3.5 Erection Requirements. The design of security fencing, using the above specified components, will include the following provisions. ASTM F 567, Standard Practice for Installation of Chain-Link Fence, may be used as installation guidance to supplement RR-F-191/GEN.

2.3.5.1 Fence Placement. Security fencing for restricted areas will consist of a single-line fence surrounding the restricted area. When specified by the local commander, two single-line fences may be used to provide additional deterrence. The two fences should be separated by a minimum of 30 feet (9.1 m) and a maximum of not more than 150 feet (45.7 m).

Buildings, structures, waterfronts, and other barriers can be used as a part of a security fence line as long as they provide equivalent protection to the fencing enclosing the restricted area. Since security fencing provides less than 10 seconds of penetration resistance, normal stud and girt walls will provide at least 1 minute of penetration resistance against a low threat level attack using limited hand tools. The designer should be primarily concerned with the windows and doorways in any wall or structure that is, or will become, a portion of the security barrier. Windows and doors that are a part of the security barrier must provide penetration resistance equal to the fence (as a minimum). MIL-HDBK 1013/1 should be consulted to determine the criteria required for windows and doors to provide penetration resistance against a low threat level.

Where portions of structures are a part of the security barrier, they must be capable of being easily observed by security personnel, i.e., guard facilities, CCTV, etc. Structures and land topography (including utility poles, trees, vines, steam pipes, etc.) will not be located so they assist passage over, around, or under a fence.

Security fencing for nuclear weapons restricted areas will consist of two single-line physical boundary fences separated by not less than 30 feet (9.1 m) or not more than 150 feet (45.7 m). Do not use walls of structures housing nuclear weapons or alert nuclear weapons systems as a part of a security fence line.

2.3.5.2 Posts, Top Rails, and Bracing. Top rails will not be specified or allowed for fabrication of security fences. Required bracing for posts will be accomplished with diagonal truss rods and tubular horizontal or diagonal bracing.

All posts and structural supports will be located on the inner side of the fencing. Posts will be installed in concrete in accordance with ASTM F 567. Posts must be vertical within plus or minus 2 degrees in two planes. Each gate, terminal, and end post will be braced with truss rods.

Truss rods will be installed diagonally, from near ground level of a gate, terminal, or end post to the top of the adjacent line post, no higher than 6 inches (152.4 mm) down from the top of the fabric. There will be no more than a 50-degree angle between the truss rod and the ground.

2.3.5.3 Chain-Link Fence Fabric Mounting. Fence fabric will be mounted on steel posts. Tension wires will either be interwoven or clipped along the top and bottom row of fabric diamonds. The wire fabric will be secured to posts and tension wires as specified in RR-F-191/4. When a more secure manner of attaching the fabric to posts is desired, a power driven fabric and wire fastener, depicted in Figure 1, may be used (see Appendix A). If the ties or fasteners are coated or plated, the coating or plating must be electrolytically compatible with the fence fabric to inhibit corrosion. Where security fencing adjoins structures, the height of the fencing should be 12 feet (3.7 m) high from the connection point with a building to a point 12 feet (3.7 m) away from the structure if required.

Figure 1.

Fabric and Wire Fastener, Power Driven.

The bottom of the fabric will extend to within 2 inches (50.8 mm) of firm soil. Where stabilization of the soil cannot be accomplished, a soil engineer should be consulted and involved in developing the fence specifi-cation. In unstable or shifting soil such as sand, the fabric should either be buried to compensate for the shifting soil or a minimum of 2 inches (50.8

mm) of the bottom selvage of the fence anchored in concrete curbs, sills, hooked steel bars, or similar types of anchoring devices extending below ground level as recommended by the soil engineer. (Frost levels should also be considered when placing curbs, sills, etc.) Even in unstable and shifting soil, the height of fabric and posts must be designed to assure that the top of the fence fabric will be maintained at 7 feet (2.1 m) above existing or anticipated ground level. This often may require that the fabric be 8 feet (2.4 m) or greater, so that sufficient material is buried below the surface or embedded in concrete sills.

At nuclear weapons storage facilities, the bottom 2 inches (50.8

mm) of the fabric will be encased in a 6-inch (152.4-mm) wide concrete sill extending approximately 12 inches (304.8 mm) into the soil around the entire perimeter. In areas where freezing is experienced, the curb must extend below the local frost level for the facility.

2.3.5.4 Outriggers. Steel outriggers will be installed to conform with RR-F-191/4 with their overhang facing outward (away from the protected site), except where the fence must be mounted directly on the property line (instead of at least 18 inches (457.2 mm) back), in which case outriggers can be modified (with exception approval) to be vertical or angle into the site. As a minimum, the outriggers will provide an additional 12 inches (304.8 mm) to the fence height. The top guard fencing adjoining gates may range from a vertical height of 18 inches (457.2 mm) to the normal 45-degree outward protection, but only for sufficient distance along the fence line to open the gates adequately. Outriggers will be permanently affixed to the fence posts with screws or by spot welding.

Nuclear weapons storage facilities will have two steel outriggers installed at opposing 45-degree angles along the top of the fence to form a "V" or a "Y" configuration.

2.3.5.5 Accessories. Secure all fastening and hinge hardware in place by peening or welding. This allows proper operation of components, while preventing disassembly of fencing components or removal of gates.

2.3.6 Special Security Features.

2.3.6.1 Clear Zones. Maintain unobstructed areas or clear zones on both sides of, and between, physical barriers surrounding restricted and non-restricted areas. These areas must be cleared of all vegetation and man-made or natural obstructions that exceed 8 inches (203.2 mm) in height. All clear zones will be clear of visual obstructions such as vines, shrubs, tree limbs, electrical and telephone poles or junction boxes, steam pipes, fire hydrants, etc., which could provide concealment for an intruder. In addition to security, interior and exterior clear zones provide a 50-foot (15.2-m) wide fire break along the security fence line.

As a minimum, a 30-foot (9-m) interior clear zone will be established inside of the fence line. When possible, a larger interior clear zone should be provided to preclude or minimize damage from thrown objects such as incendiaries or bombs.

An exterior clear zone of at least 20 feet (6.1 m) or greater will be established outside of the fence line. To accomplish this, the fence must be placed a minimum of 20 feet (6.1 m) inside the facility property line. As an exception for perimeter barriers along station property lines, OPNAVINST 5530.14B allows utility poles, signboards, and trees limbs to be in a perimeter clear area as long as these elements are greater than 14 feet (4.3

m) from the perimeter barrier and provided these elements do not obstruct the visibility of the guards. The designer may be required to stagger the perimeter barrier so that the minimum distance between these elements and the security fence is 14 feet (4.3 m) or more. Otherwise these elements must be removed.

At some activities it may not be feasible, practical, or even possible to provide the required minimal clear zones due to various reasons such as lack of Government controlled property, previous construction encroaching the required clear area, etc. In these cases, OPNAVINST 5530.14B requires that compensatory measures and procedures be employed. Construction of any security or perimeter fence that does not provide the minimum clear zones cited above must receive prior approval by an exception as set forth in OPNAVINST 5530.14B. As an alternative when the exterior 20-foot (6.1-m) clear zone cannot be established on Government controlled property, local property owners should be approached to obtain permission to clear and maintain the clear zone outside of the fence.

At nuclear sites, clear areas will extend 30 feet (9.1 m) outside the outer fence line, the entire area between the fences, and 30 feet (9.1 m) inside the inner fence line. These clear areas will be free of all obstacles, topographical features, and visual obstructions including trees, electrical and telephone poles or junction boxes, steam pipes, fire hydrants, etc., exceeding 8 inches (203.2 mm) high.

2.3.6.2 Patrol Roads. When the patrolled perimeter barrier encloses an area generally greater than 1 square mile (2.6 square kilometers (km)), an interior perimeter road in all areas not affected by impassable terrain features must be provided for use by security patrols. Patrol roads that pass through clear areas must be designed to preclude concealment for intruders.

Drainage culverts passing under the road in clear zones must be secured at all openings as described herein for drainage and culverts under fences. Drainage ditches along the side of patrol roads shall be designed utilizing shallow or low angle side slopes which shall not obscure observation from a 4-foot (1.2-

m) high line of sight above grade of roadway.

2.3.6.3 Signs. Perimeter security fences for restricted areas will be posted with signs. See OPNAVINST 5530.14B. Signs will be posted on security fences at no less than 200-foot (60.9-m) intervals along the entire perimeter.

If the perimeter is the exterior wall of a building or structure, it will be posted at the point of ingress. Where a language other than English is prevalent, warning signs will be posted in both languages.

For nuclear sites, signs will be provided as prescribed in paragraph 3-701, Warning Signs, of OPNAVINST C8126.1. When military working dogs will be used with security forces, appropriate warning signs will be provided as prescribed in Appendix A of OPNAVINST C8126.1.

2.3.6.4 Drainage Culverts and Utility Openings. Special protective measures must be designed for culverts, storm drains, sewers, air intakes, exhaust tunnels, and utility openings, that:

a) Pass through cleared areas.

b) Traverse under or through security fences.

c) Have a cross-section area of 96 square inches (61,939 square

mm) or greater, with the smallest dimension being more than 6 inches (152.4 mm).

Such openings and barrier penetrations will be protected by securely fastened grills, locked manhole covers, or other equivalent means that prevent entry or provide security penetration resistance of approximately 10 seconds. When grills are fabricated for this purpose, they may be made by cross-hatching 3/8-inch (9.5-mm) steel bars 9 inches (228.6 mm) on center.

The bars will be welded at their intersections. Grills used for culverts will always be placed outside the secure area. For steel pipe, the grill ends will be welded to the pipe as shown in Figure 2. For concrete pipe, the grill ends will be welded to a steel rim that fits snugly over the concrete pipe. The rim and grillwork will be fastened over the concrete pipe and bolted or pinned to the rim of the concrete pipe as shown in Figure 3. As an alternative, the grill ends can be embedded in a concrete headwall that encapsulates the concrete pipe. Care must be taken during design to assure that bars and grills across culverts, sewers, storm drains, etc., are not susceptible to clogging. This must be considered early during the security fence planning phase. Culverts, storm drains, and sewers must be designed with a debris catcher to permit either rapid clearing or removal of grating for cleaning when required. If the inlet is outside the fence line, the debris catcher and grating will be incorporated into the same structure. If the outlet is outside the fence line, the debris catcher will be on the inlet side inside the fence line and the grating on the outlet side. A solution is shown in

Figure 4 (note that the removable grate is locked in place as an added security measure).

Figure 2.

Steel Culvert Grill.

Figure 3.

Concrete Culvert Grill.

Figure 4.

Removable Grating for Culverts.

As an alternative, drainage structures may be constructed of multiple pipes, each pipe having a diameter of 10 inches (254 mm) or less, joined to each other and to the drainage crossing. An economical solution to secure metal drainage structures is to weld short (approximately 6-inch (152.4-mm) long) multiple pipes, with diameters less than 10 inches (254 mm), in the "in-flow" end of the drainage culvert as shown in Figure 5.

2.3.6.5 Drainage Crossings. Where security fences must cross drainage ditches or swales, the designer must assure that the intruders are prevented from passing under the fence. Where water flow is minor and generally not a problem, the main fence may be carried across a ditch or swale with additional fence added below. The fence added below must be attached every 2 inches (50.8 mm) along the intersection of the two fence sections and either attached to a series of ground stakes secured to the sides and bottom of the ditch, or embedded in a concrete sill in the ditch or swale (see Figures 6 and 7).

Where heavier flows of water are anticipated, a cross-hatched screen type arrangement must be provided below the fence using vertical and horizontal bars similar to those described in the above paragraph. The flow capacity must first be analyzed to determine the size grillwork that will accommodate the maximum amount of water that may be experienced. Rainy seasons and possible debris that can be carried by the flow must be taken into consideration. In any case, not more than 9 inches (228.6 mm) will be allowed between either vertical or horizontal bars, and bars will be welded at each intersection (Figure 8).

Figure 5.

Large Culvert with Short Honeycomb Pipes.

Figure 6.

Swale Crossing with Ground Stakes.

Figure 7.

Swale Crossing Embedded in Concrete.

Figure 8.

Bar Grill Embedded in Concrete.

MIL-HDBK-1005/3, Drainage Systems, provides considerable information concerning design criteria and planning guidelines for drainage systems. While this guidance should be utilized to design drainage for the restricted area, the designer must assure the security aspects of the design take precedence over the drainage guidance contained in the MIL-HDBK.

2.3.6.6 Tunneling. A soils engineering analysis should be made where soft or shifting soil, such as sand, is encountered. Since the penetration resistance of a security fence approaches 15 seconds, the year-round soil condition at the facility must also provide 15 seconds as a minimum of tunneling resistance. Where the soil analysis indicates tunneling can be accomplished in less than 15 seconds, the fence will be embedded in a continuous concrete curb. The recommended depth of the curb will be determined from the soil analysis and the frost line at the facility.

Since the entire fence line at nuclear sites is embedded in a continuous concrete curb, as shown in Figure 9, tunneling should be prevented except in the most severe cases of shifting sand. At nuclear sites with very sandy terrain, a soils engineering analysis should also be made to determine the recommended depth of the concrete curb. When specifying the depth of the concrete curb and concrete embedded fence poles, the designer should also consider the frost-line for the subject area to assure that heaving of the posts and curb cannot occur during the winter.

Figure 9.

Chain-Link Fence Embedded in Concrete Sill.

2.3.7 Maintenance Considerations. Consider the following when designing chain-link fencing:

a) Fence components may require additional protective coatings in salt-laden and highly corrosive areas, e.g., plastic coating over galvanized steel fabric.

b) Rapid growth of vegetation in fertile areas and rainy climates may justify paving the area under the fence and a portion or all of the clear zones.

c) Consideration should be given for equipment, i.e., mowers, tractors, etc., required to maintain vegetation below 8 inches (203.2 mm) and to broadcast defoliants or sterilants.

2.3.8 Erosion Control. For erosion control, refer to MIL-HDBK-1005/3, Drainage Systems and NAVFAC DM-5.14, Groundwater Pollution Control. Where erosion control measures advised in either MIL-HDBK-1005/3 or DM-5.14 violate the security requirements contained herein, the security requirements take precedence.

2.3.9 Grounding. Generally, grounding is not required for chain-link fences mounted on metal posts. However, fences shall be grounded on each side of every gate, at points 150 feet (45.7 m) on each side of high-tension line crossings, and at 150-foot (45.7-m) intervals along the fence where high-tension lines (as defined by ANSI C2) are directly overhead and run parallel to the fence. Fences shall be grounded every 1,000 feet to 1,500 feet (304.8 m to 457.2 m) of length when fences are in isolated places and at lesser distances depending upon proximity of fence to public roads, highways, and buildings. Grounding will also be provided for fenced conventional AA&E and nuclear weapons storage areas. The ground shall be made with a bolted connection at a fence post by the use of No. 2/0 AWG (67.4 sq mm) copper cable. Where plastic coated fabric is used, the post shall be bolted, and each strand of the fence shall be brazed to the metallic bare conductor. The conductor shall then be grounded. For additional information, see MIL-HDBK- 1004/6, Lightning Protection.

2.4 Special Requirements for Fences Equipped with Intrusion Detection Systems (IDS) Sensors. IDS sensors are often placed on security fences and clear zones to detect aggressors attempting to gain access to an asset.

Exterior sensors consist of four major types of field sensors: beam sensors, fence disturbance sensors, seismic sensors, and video motion detectors. If exterior IDS sensors are to be included in the fabrication and installation of security fences, the criteria presented in DM-13.02, Commercial Intrusion Detection System (IDS) should be used.

2.4.1 Taut-Wire Fences. Taut-wire sensored fences may be installed around designated restricted areas, except for AA&E and nuclear restricted areas, when IDS sensors are desired to increase the detection capability of the security force.

Taut-wire sensored fences will be 7 feet (2.1 m) high and have a 31-inch (787.4-mm) double outrigger equipped with sensor devices. The sensor system shall consist of horizontal barbed wire spaced approximately 4 inches (101.6 mm) apart and connected to a central detection device tensioned between two anchor devices. Before designing taut-wire sensored fences, Naval Electronic Systems Engineering Center (NAVELEXCEN) should be contacted for the latest installation specifications.

2.4.2 Special Requirements. In order to maintain optimal performance for electromechanical fence sensors, it is imperative that the chain-link fence be well constructed with tight tensioning maintained throughout the fence line. The fence construction must be adequate to support the added weight of the IDS. This type of sensor requires frequent fence maintenance.

For additional details and information concerning fence design requirements for specific fence IDS systems, contact NAVELEXCEN, Code 33, at DSN 563-2030, commercial 803-745-4600 or write:

Naval Electronic Systems Engineering Center Code 33

4600 Mariott Drive Charleston, SC 29418-6504

2.4.3 IDS Funding. MILCON funds cannot be used for design or

construction of IDS. MILCON projects may include fence IDS systems funded by the customer.

2.5 Penetration-Resistant Barriers. Recent terrorist incidents involving the use of suicide-type crash entry forces the consideration of vehicle barriers capable of stopping large vehicles traveling at high speed.

Crash tests of chain-link fences, similar to the chain-link fence required by this handbook, allowed full penetration with no personnel injuries of both a 1-1/2-ton (1360.7-kg) and 2-ton (1814.4-kg) vehicle traveling at 50 miles per hour (80.5 km per hour). An analysis of crash test data indicates that, unless enhanced by the addition of cables, fences offer little protection against penetration. Consequently, to meet a vehicle threat, fence reinforcement measures may be required to maintain security of a restricted area. Crash tests performed on a chain-link fence reinforced with a 3/4-inch (19.1-mm) aircraft cable restricted penetration of a 2-ton (1814.4-kg) vehicle traveling at 50 mph (80.5 km/h) to 26 feet (7.9 m).

When selecting barriers for penetration resistance, the designer should choose active or passive barriers based on their capacity to stop the threat vehicle at the maximum speed it could attain in its approach.

a) Passive Barriers. Use passive barriers where unmovable barriers are needed, such as along a perimeter chain-link fence.

b) Active Barriers. Use active barriers where vehicles must be allowed passage, but the capacity to stop them must also be maintained.

2.5.1 Reinforcement of Perimeter Chain-Link Fence. A reasonable approach to reinforce a standard chain-link perimeter fence to resist a vehicle attack is both simple and aesthetic. Place a 3/4-inch (19.1-mm) diameter aircraft cable, conforming to MIL-W-83420, along the fence line, between the fence posts and the chain-link fabric as shown in Figure 10.

Fasten the cable with 1/2-inch (12.7-mm) U-clamps (SAE Grade 3 or better) at a height of approximately 30 inches (762 mm) from ground level. Terminate each cable end with either three wire rope clamps (MS16842) or a wire rope hydraulically swaged press fitting (MIL-P-80104). The cable end will be attached to one end of a 3/4-inch (19.1-mm) round turnbuckle (MS51561) with double eye ends which in turn will be attached to the deadman eyebolt (MIL-B- 45908) by a 3/4-inch (19.1-mm) anchor shackle (SAE Grade 8 or ASTM A 490).

The deadman anchor will be a concrete cube, approximately 3 by 3 by 3 feet (1 by 1 by 1 m). Eyebolts captured in the deadman anchors will have either a welded "T" or "L" end embedded in the concrete as shown in Figure 11.

As a minimum, 2 feet (0.610 mm) of the eyebolt and its welded extension will be captured within the concrete of the deadman. The shaft of the eyebolt will be either in-line with the attached cable or the eye of the eyebolt will be flush with the surface of the deadman. Anchors shall be placed at a minimum of 200-foot (60.9-m) intervals and a maximum of 1,000-foot (304.8-m) intervals on the inside of the perimeter fence with the front edge of the deadman flush with the fence fabric. The top of the deadman will be either flush or buried below the surface as long as the eye of the eyebolt is above ground level.

Cables must overlap as shown in Figure 10 before terminating at a deadman so that no voids in the cable occur along the perimeter. If additional hardening is desired, a second cable should be placed about 5 inches (127 mm) above the first cable and attached as described above. It may be anchored to the same deadmen used by the first cable system.

When gates form a portion of the fence line being protected by a vehicle restraint cable system, then the gate cable system described in Section 3 must be interconnected to the fence cable system to ensure continuity of the cable system. Often, natural barriers such as mountains, cliffs, rivers, seas, trees, vegetation, or other terrain protect the fence from vehicle attack. The vehicle restraint cable system should not be used along portions of the fence line that are otherwise protected by natural barriers, such as large boulders, trees, natural ravines, and ditches.

Figure 10.

Steel Cable-Reinforced Chain-Link Fence.

Figure 11.

Deadman Anchor.

2.5.2 Additional Barriers. Alternatives to the barriers listed above, along with a decision tree for vehicle barrier selection and design criteria, can be found in the NCEL Terrorist Vehicle Bomb Survivability Manual, July 1988. Many of the passive barriers contained in the manual may be more convenient, suitable, or economical to install than the fence cable vehicle restraint system. The fence location should drive the actual selection of a barrier or barrier system. Some examples of active and passive vehicle barriers are:

a) b) c) d)

e) median barriers.

f) g) h) i)

Active (pop-up) type vehicle barriers.

Both active ("pop-up") and passive bollards.

Across-the-road bar-type barriers.

Dragnet systems.

Concrete planter boxes, jersey bounces, anchored concrete

Buried heavy equipment tires.

Concrete and concrete block walls.

Sand filled 55-gallon (208.2-liter) drums.

Highway-type guard rails and cable systems.

Section 3: GATES

3.1 Application. Gates facilitate control of authorized traffic and its flow. They establish specific points of entrance and exit to an area defined by fences. They also function to limit or prohibit free flow of pedestrian or vehicular traffic, while establishing a traffic pattern for restricted areas.

3.2 Related Criteria. Gates, as a part of perimeter fences, must be as effective as their associated fence to provide an equivalent deterrent.

Gates will normally require additional hardening features due to their location across entrance roads and the inherent vulnerability of their hinges and latches. Gates are known to be the weakest point in the perimeter security fence and as such, you must pay attention to their requirements when designing security fencing.

Materials used in fabricating and erecting chain-link gates must be the same as the materials used for the associated chain-link fence. As for security fences, aluminum pipe, poles, fabric, or accessories will not be used or specified for security gate components. Use American Society for Testing and Materials (ASTM) standards to supplement Federal specifications when further detail or criteria is desired.

3.3 Types of Gates. Federal Specification RR-F-191/2 is the basic criteria document for security fence gate design. It provides specifications for the following eight types of chain-link fence gates:

a) Type I - Single Swing Gates.

b) Type II - Double Swing Gates.

Gates.

c) Type III - Single Cantilever Sliding Gates, Wheel Sliding

d) Type IV - Double Cantilever Sliding Gates.

e) Type V - Single Overhead Sliding Gates.

f) Type VI - Double Overhead Sliding Gates.

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