Significance and Use
The success or failure of any attempt to forcefully penetrate a fence system is dependent upon three primary factors that collectively define the threat
Normally, a test procedure of this scope would be supported by years of laboratory testing intended to qualify and accurately reproduce the destructive effects of a variety of tools, implements, and devices. However, rapidly changing social conditions have created an immediate need for building components resistant to evolving forced entry techniques. Accordingly, the procedures presented herein are based more on field experience than laboratory analysis. They are more representative than inclusive, are intended to provide a basis for the comparative evaluation of different fence systems using forced penetration procedures, ballistic tests and impact testing, and are not primarily intended to be used to establish or confirm the absolute prevention of forced entries.
1.1 The forced entry resistance of fence systems is evaluated relative to three levels of forced entry threat using the limited hand tool inventory outlined in Table 1. It also establishes a system for rating the forced entry resistance of those systems (see Table 2). The tools specified to be used for testing at each threat level are those that are known to have a maximum destructive effect on structures and their sub-assemblies and are readily available to aggressors categorized as posing that level of threat.
1.1.1 Low Threat Level (L)—Specifically exempted from the inventory of available tools for the low (L) threat level category are power tools (gasoline, electric or hydraulic), and devices requiring more than one person to transport and operate.
1.1.2 Medium Threat Level (M)—Specifically exempted from the inventory of available tools for the medium (M) threat level category are power tools requiring an outside power source or self contained gasoline or battery driven tools and devices requiring more than two persons to transport and operate.
1.1.3 Aggressive Threat Level (A)—Specifically exempted from the inventory of available tools for the high (H) threat level category are devices requiring more than two persons to transport and operate.
1.2 The ability of a fence system to offer protection from bullets fired from a rifle or handgun would be beneficial particularly in Border Fence areas where security personnel can be targets during patrol activities. Accordingly, a limited test using a .38 Special handgun and a 7.62-mm rifle is performed to determine if any level of protection is provided by the fence system.
1.3 The ability of a fence system to provide impact resistance from a 4000 pound mass vehicle moving at a velocity of 20 MPH at a modest cost will provide relative guidance as to the strength of a security fence system in resisting low impact situations.