Wednesday, August 11, 2010

Perimeter Fencing

It has been a while since I’ve actually addressed physical security measures for high-risk chemical facilities, so I guess that it is time to look at some of these important issues. I’ll start with one of my personal favorites, perimeter fencing. I’ll start this discussion off with a true story… True Story The chemical facility that I worked at was in an industrial park with the typical 6ft industrial chain link fence with an 18” barbwire outrigger. When the facility was not operating on weekends there was a single, elderly security guard patrolling the facility and manning the front gate. He actually spent most of his time in the break room in the office building; the air conditioning/heat was better there. I mentioned this to the Plant Manager one day, and he was interested in how I knew this since the gate was locked and could only be operated by the guard from inside the gate shack. I told him that I frequently entered the facility on weekends by climbing the fence since I couldn’t get the guard’s attention. He looked at me and my middle-aged chemist’s body and flatly stated that he didn’t believe me. I took him out to the front gate and showed him how easy it was to climb the fence. He stopped kidding me about the excess weight I carried. Purpose of Fencing The whole point of this story is that fences are not designed to stop determined intruders. Any fence can be breached. Some fences may delay the stealthy intruder who doesn’t want to be detected, but all fences can be breached by someone with just a small amount of training. Over, under, or through, at most a fence will delay someone determined to gain access. Without additional security measures in place a fence simply exists to mark a boundary beyond which it is illegal to precede without permission. Without such a clearly delineated border a casual intruder cannot typically be prosecuted for trespass. A simple fence is designed to keep honest people honest. Barrier Fencing To turn a fence into a barrier that will be a stronger deterrent to intruders requires a detection and response system. The detection portion of the system will be designed to determine when someone tries to breach the fence. The response portion will provide a reaction to the intruder that will impede the intruder from progressing further into the facility. There are a wide variety of detection systems that can be used in conjunction with a fence. Security guards can be stationed around the perimeter or be used to conduct roving patrols. A wide variety of intrusion detection systems (IDS) using any number of different types of sensors can be employed to detect someone approaching and then breaching the fence. Intrusion Response Systems Response systems have a two-fold purpose. First they may be used to investigate an alarm signal to determine if it is actually an intruder or some sort of system transient. The more sensitive an intrusion detection system is the more often they will typically have false alarms. Every alarm must be investigated or the whole purpose of the detection system is violated. Video surveillance systems can be used to perform this investigative function. A system operator would respond to an IDS alert by pointing the appropriate camera at the point of the reported intrusion and determining if someone had actually penetrated the fence line. The use of video systems has the added benefit of providing documentation of the intrusion for use in subsequent prosecution. The second purpose of the response system is to prevent the intruder from further penetration of the facility. This can either be done by intercepting and detaining the intruder so that they can be turned over to law enforcement personnel for subsequent prosecution. The alternative is to provide sufficient incentive for the intruder to stop and leave the facility. Typically security guards are used as the response system. One would expect that a response team (2 or more individuals) would move to the point of the suspected intrusion to determine if a penetration actually occurred. If intruders were detected they would either be chased from the facility or convinced to surrender to the security force. There are other automated systems being developed for the response function. These could include a variety of robotic systems. Other remote controlled or automated systems, up to and potentially including weapons, could conceivably be used. Armed Security Personnel One cannot talk about security response personnel without addressing the issue of whether or not to arm such personnel. Many high-risk chemical facilities are very reluctant to even discuss arming security personnel because of the safety considerations involved in discharging a conventional fire arm around potentially flammable environments. Such safety concerns are of course a legitimate consideration. There are also legal concerns that must be addressed. The other thing that must be taken into account is the possibility of security personnel encountering armed intruders. If there is a significant chance that intruders will be armed, then security personnel need to be armed if for no other reason than to defend themselves. Detailed Considerations This has been just a brief look at some of the general issues that must be considered when looking at the issue of perimeter fencing for high-risk chemical facilities. The details of how to select specific systems for a particular facility require a detailed analysis of the facility situation. Few facilities will have the in-house expertise necessary to determine the optimum system utilization for their particular situation. This is one of the many reasons that facilities will turn to security contractors to set up their systems.

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