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Chapter 14

Fence Standards

Chain-Link Fence

Manufacturers Institute

Recommendations

Chain-link fencing has been the product of choice for security fencing for over 60 years because of its

strength, corrosion resistance, “see-through capabilities,” ease of installation, versatility, variety of

product selection, and value. A chain-link fence is one of the primary building blocks for a facility’s

perimeter security system.

The physical security barrier provided by a chain-link fence provides one or more of the following

functions:

• Gives notice of a legal boundary of the outermost limits of a facility.

• Assists in controlling and screening authorized entries into a secured area by deterring entry

elsewhere along the boundary.

• Supports surveillance, detection, assessment, and other security functions by providing a zone for

installing intrusion detection equipment and closed-circuit television (CCTV).

• Deters casual intruders from penetrating a secured area by presenting a barrier that requires an overt

action to enter.

• Demonstrates the intent of an intruder by their overt action of gaining entry.

• Causes a delay to obtain access to a facility, increasing the possibility of detection.

• Creates a psychological deterrent.

• Reduces the number of security guards required and frequency of use for each post.

• Optimizes the use of security personnel while enhancing the capabilities for detection and

apprehension of unauthorized individuals.

• Demonstrates a corporate concern for facility security.

• Provides a cost-effective method of protecting facilities.

Security Planning

Chain-link fence enhances the goals of good security planning. In-depth security planning takes into

consideration the mission and function, environmental concerns, threats, and the local area of the

facility to be secured. This can be translated into an A-B-C-D method that points out the values of

chain-link fencing to a security program.

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A. AIDS to security. Chain-link fencing assists in the use of other security equipment, such as the use

of intrusion detectors, access controls, cameras, and so forth. Chain-link fences can be employed as

aids to protection in an exterior mode or an internal protected property, as a point protection, and

for general protection as required.

B. BARRIERS for security. These can be buildings, chain-link fences, walls, temporary checkpoints,

and so on.

C. CONTROLS support the physical security chain-link fences and barriers, such as an access control

system tied into vehicle gates and pedestrian portals, various level identification badges and

temporary badges, security escorts, and internal procedures.

D. DETERRENTS such as a chain-link fence, guards, lighting, signage, and checkpoint control

procedures are a few of the deterrents that ensure intruders will consider it difficult to successfully

gain access.

When properly used, the aspects of the A-B-C-D method reinforce and support each other. Thus a

chain-link fence is also a deterrent, and a barrier, if need be. By combining A-B-C-D, sufficient

obstacles are created to prevent an intruder from obtaining information that is being worked on during

the day in the controlled access area and then is protected at night, on weekends, and on holidays

through the implementation of the security in-depth concept.

More important, keep in mind that a chain-link fence is the common denominator of the A-B-C-D

system and will reduce overall risk, secure the environment, and reduce security costs if designed and

installed properly. However, believing that a fence will eliminate all illegal access is not prudent. A

fence system will only delay or reduce intrusion.

To ensure the effectiveness of the facility security fence program, it is recommended that a

maintenance program be developed for the proper maintenance of the fence system, gates, gate

operators, and related access controls.

Material Specifications

Material specifications for chain-link fence are listed in the following:

• (CLFMI)Chain-Link Fence Manufacturers Institute Product Manual

• American Society of Testing Materials (ASTM), volume 01.06

• Federal Specification RR-F-191 K/GEN, May 14, 1990

• ASTM F 1553, “The Standard Guide for Specifying Chain-Link Fence,” provides the appropriate

information to develop a specification document

Framework

The framework for a chain-link fence consists of the line posts, end posts, corner posts, gateposts,

and, if required, a top, mid, bottom, or brace rail. The Federal Specification and the CLFMI “Wind

Load Guide for the Selection of Line Post Spacing and Size” provide recommended post sizes for theCo py ri gh t @ 20 12 . Bu tt er wo rt h- He in em an n.

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various fence heights. However, the latter document also provides choices of line post types, sizes,

and spacings to accommodate selected fence heights and fabric sizes for wind loads at various

geographical project locations. The , ASTM F1043, and ASTM F1083, asCLFMI Product Manual

well as the Federal Specification, list the material specifications for the framework.

Chain-Link Fabric

The material specifications for chain-link fabric are thoroughly spelled out in the CLFMI Product

, ASTM, and Federal Specifications. The choice of chain-link fabric will govern the desiredManual

security level, and the various fabric-coating choices will govern the corrosion resistance.

Light-gauge residential chain-link fabric will not be considered in this document. Provided are only

those chain-link fabrics that offer a level of security, thus the gauge of wire and mesh size has been

narrowed down to the following:

minimum break strength of 850 lbf11 gauge (0.120 inches diameter)—

minimum break strength of 1,290 lbf9 gauge (0.148 inches diameter)—

minimum break strength of 2,170 lbf6 gauge (0.192 inches diameter)—

Mesh sizes to consider (mesh size is the minimum clear distance between the wires forming the

parallel sides of the mesh) are 2-inch mesh, 1-inch mesh, and -inch mesh. Consider the following

regarding mesh size:

• The smaller the mesh size, the more difficult it is to climb or cut.

• The heavier the gauge wire, the more difficult it is to cut.

The various mesh sizes available in the three previously discussed gauges are listed in the order of

their penetration resistance/security:

1. Extremely high security: -inch mesh 11 gauge

2. Very high security: 1-inch mesh 9 gauge

3. High security: 1-inch mesh 11 gauge

4. Greater security: 2-inch mesh 6 gauge

5. Normal industrial security: 2-inch mesh 9 gauge

Gates

Gates are the only moveable part of a fence and therefore should be properly constructed with

appropriate fittings. Chain-link gate specifications are listed in the , ASTM,CLFMI Product Manual

and Federal Specifications.

Limiting the size of the opening increases vehicular security and reduces the possibility of one

vehicle passing another, and the smaller opening reduces the open close cycle time. The cantilever

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slide gate is the most effective for vehicle security, especially one that is electrically operated and tied

into an access control system. High-speed cantilever slide gate operators are available for certain

applications.

Pedestrian/personnel gates can be constructed using a basic padlock or designed with an electrical

or mechanical lock or a keypad/card key system tied into an access control system. Pre-hung

pedestrian gates/portals installed independent of the fence line are available to isolate the gate from

fence lines containing sensor systems thus reducing possible false alarms.

Design Features and Considerations

Some basic design features to consider that enhance security:

• The higher the barrier the more difficult and time-consuming it is to broach.Height.

• Omission of a rail at the top of the fence eliminates a handhold, thus makingEliminating top rail.

the fence more difficult to climb. A 7-gauge coil spring wire can be installed in place of the top rail.

• Addition of three or six strands at the top of the fence increases the level ofAdding barbwire.

difficulty and time to broach. When using the three-strand 45-degree arm it is recommended to

angle the arm out from the secured area.

• Barbwire arms are normally held to the post by the topBolt or rivet barbwire arms to post.

tension wire or top rail. For added security they can be bolted or riveted to the post.

• Stainless steel barbed tape added to the top and in some cases the bottom ofAdding barbed tape.

the fence greatly increases the difficulty and time to broach.

• Addition of a bottom rail that is secured in the center of the two line postsAdding bottom rail.

using a 3/8-inch diameter eye hook anchored into a concrete footing basically eliminates the

possibility of forcing the mesh up to crawl under the fence. The bottom of the fence, with or without

a bottom rail, should be installed no greater than 2 inches above grade.

• Burying the fabric 12 inches or more will also eliminate the possibilityBury the chain-link fabric.

of forcing the mesh up.

• One of the security features of a chain-link fence is visibility, allowingColored chain-link fabric.

one to monitor what is taking place inside or outside of the fence line more efficiently. Color

polymer-coated chain-link fabric enhances visibility, especially at night. Complete polymer-coated

systems including coated fabric, fittings, framework, and gates, increase visibility and provide

greater corrosion resistance, especially for use in areas adjacent to the seacoast.

• It is not uncommon to add an additional line of internal securityDouble row of security fencing.

fencing 10–20 feet inside the perimeter fence. In many cases double rows of fencing are used with

sensors and detectors, or with a perimeter patrol road in the area between the fences.

• In wooded or high grass areas it is advisable to clear and grub a clear zone on eitherClear zone.

side of the fence to aid surveillance.

• Many situations require the need of a separate interior fence to addInternal security fencing.

another level of security for a particular building, piece of equipment, or location.C op yr ig ht @ 2 01 2. B ut te rw or th -H ei ne ma nn .

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• This eliminates the removal of the bolt nut.Peen all bolts.

• This adds another level of security to the fence system.Addition of a sensor system.

• Increases visibility as well as raises the level of psychological deterrent.Addition of lighting.

• Installed along the fence line, signs are important to indicate private secured areasSignage.

(violators may be subject to arrest), and possibly note the presence of alarms and monitoring

systems.

Typical Design Example

We have chosen for our example to list the referenced specifications separately to help identify the

various items that need to be specified. The specification writer may use this format or the standard

construction specifications institute (CSI) format in developing their document.

In developing specifications for a typical chain-link fence, the design could be described as

follows:

80 high chain-link fence plus 10, three strands of barbwire at top for a total height of 90, consisting of

2 inches mesh 6-gauge chain-link fabric, _____ o.d. or _____ “C” line posts spaced a maximum of

100 o.c., 7-gauge coil spring wire at top, secured to the chain-link fabric with 9-gauge hog rings

spaced not greater than 12 inches, -inch o.d. bottom rail secured in the center with a -inch diameter

galvanized steel eye hook anchored into a concrete footing, chain-link fabric secured to line post and

rail at a maximum of 12 inches o.c. using 9-gauge tie wire.

_____ o.d. end and corner posts complete with -inch o.d. brace rail, -inch truss assembly,

12-gauge tension bands secured at a maximum of 12-inch o.c., tension bar, necessary, fittings, nuts,

and bolts.

Chain-link fabric shall comply with ASTM ____.

Post and brace rail shall comply with ASTM ____.

Barbwire shall comply with ASTM ____.

Fittings, ties, nuts, and bolts shall comply with ASTM ____.

Coil spring wire shall comply with ASTM ____.

Reference is made to ASTM as an example. All chain-link specifications, fabric, posts, fittings gates,

and so forth are referenced in ASTM F 1553, Standard Guide for Specifying Chain-Link Fence.

A typical design/specification for gates would be listed as follows:

Pedestrian/personnel swing gates shall have a 40 opening by 80 high plus 10, and three strands of

barbwire on top. Gate frames shall be fabricated from 2-inch o.d. or 2-inch square members, welded

at all corners. Chain-link fabric shall be installed to match the fence line unless otherwise specified.

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Gateposts shall be _____ o.d. complete with 1-inch o.d. brace rail, -inch diameter truss assembly,

12-gauge tension bands secured a minimum of 12 inches apart, necessary tension bar, fittings, and

nuts and bolts.

Chain-link fabric shall comply with ASTM ____.

Swing gates shall comply with ASTM ____.

Gateposts size, o.d., shall comply with ASTM ____.

Gateposts shall comply with ASTM ____.

Fittings shall comply with ASTM ____.

Cantilever slide gates shall be of the opening sizes as indicated on the drawings, having a height of

80 plus 10, and three strands of barbwire. (The construction and design of cantilever slide gates vary;

therefore it is best to list the specific specification.) Cantilever slide gates shall be constructed per

ASTM F 1184, Class ____. Chain-link fabric shall match the fence line unless otherwise specified.

(Cantilever slide gates require 4-inch o.d. gateposts; larger or smaller posts are not recommended.)

The 4-inch o.d. gate-posts shall be complete with 1-inch o.d. brace rail, -inch diameter truss assembly,

12-gauge tension bands secured a minimum of 12 inches apart, necessary tension bar, fittings, and

nuts and bolts.

4-inch o.d. gatepost and 1-inch o.d brace rail shall comply with ASTM ____.

Fittings shall comply with ASTM ____.

Chain-link fabric shall comply with ASTM ____.

Installation

Installation for the fence line, terminal posts, and gates varies depending on the security level

required, site conditions, geographical location, and soil and weather conditions. The best documents

to assist you in this process are ASTM F 567, “Standard Practice for Installation of Chain-Link

Fence,” and the CLFMI “Wind Load Guide for the Selection of Line Post Spacing and Size.”

Project Inspection

Improper material or installation can have a dramatic effect on the required security. It is important to

verify that the project materials are in compliance with the contract specifications and that the fence

has been installed properly. Procurement or facility managers may want to consider a mandatory

requirement of their reviewing material certifications and shop drawings prior to the start of the

project. This will ensure that proper products will be installed and that specific installation guidelines

have been provided. CLFMI offers a document to assist in this process.Field Inspection Guide

Reference is made to various fence specifications; complete information can be obtained by

contacting the following:

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10015 Old Columbia Road, Suite B-215, Columbia, MDChain-Link Manufacturers Institute

21046; Phone: 301-596-2583; http://www.chainlinkinfo.org/

Federal Specification RR-191K/GEN Bldg. 4D, RobbinsStandardization Documents Order Desk

Ave., Philadelphia, PA 19120-5094

100 Barr Harbor Drive West, Conshohocken, PA, 19428; Phone: 610-832-9500; ASTM http://www

.astm.org/

99 Canal Center Plaza, Suite 300, Alexandria, VA 22314;Construction Specifications Institute

Phone: 800-689-2900; [email protected]

In addition to information available from the above-listed organizations, design and engineering

assistance is available through a number of CLFMI member firms. To find these firms, click on

“Product/Services Locator” and select “All United States” and “Security Chain-Link Fence Systems”

from the product listing. Then click “GO” and the firms who can assist you will be listed.

FIGURE 14-1

FIGURE 14-2

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http://www.chainlinkinfo.org/

http://www.astm.org/

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FIGURE 14-3

FIGURE 14-4

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FIGURE 14-5 Typical detail of an 8-foot-high fence with 1-foot, three-strand barbed wire security.

Note: The information in this chapter has been provided as a public service to assist in the design of appropriate security fencing. The

Chain-Link Fence Manufacturers Institute disclaims any responsibility for the design and operation of specific security fence systems.

Permission obtained to be reproduced in 2012.

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Chapter 15

Stages of Fire

Inge Sebyan Black, CPP

Stages Of Fire

1. Fuel, oxygen and heat join together in a sustained chemical reaction. At this stage, a fireIgnition.

extinguisher can control the fire.

2. With the initial flame as a heat source, additional fuel ignites. Convection and radiationGrowth.

ignite more surfaces. The size of the fire increases and the plume reaches the ceiling. Hot gases

collecting at the ceiling transfer heat, allowing all fuels in a room to come closer to their ignition

temperature at the same time.

3. Fire has spread over much if not all the available fuel; temperatures reach theirFully developed.

peak, resulting in heat damage. Oxygen is consumed rapidly.

4. The fire consumes available fuel, temperatures decrease, and the fire gets lessDecay (burnout).

intense.

How Fire Spreads

Fire spreads by transferring the heat energy from the flames in three different ways.

• The passage of heat energy through or within a material because of direct contact,Conduction.

such as a burning wastebasket heating a nearby couch, which ignites and heats the drapes hanging

behind, until they too burst into flames.

• The flow of fluid or gas from hot areas to cooler areas. The heated air is less dense andConvection.

rises, while cooler air descends. A large fire in an open area produces a plume or column of hot gas

and smoke high into the air. But inside a room, those rising gases encounter the ceiling. They travel

horizontally along the ceiling forming a thick layer of heated air, which then moves downward.

• Heat traveling via electromagnetic waves, without objects or gases carrying it along.Radiation.

Radiated heat goes out in all directions, unnoticed until it strikes an object. Burning buildings can

radiate heat to surrounding structures, sometimes even passing through glass windows and igniting

objects inside.

Four Ways to Put Out a Fire

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