The events of September 11, 2001 changed the way business thought about perimeter security and access control. Rather than just a barrier to keep intruders out, fences and gates are installed with protection against potential terrorist attacks in mind. Perimeter security is now being looked at to determine the best ways to stay safe.

Of course, the heightened sense of alert that followed 9-11 is only one of dozens of reasons why organizations or private residents choose to install some sort of access control. For example, Charlie Weston, president of Guardian Fence in Columbia, S.C., points out that construction sites and utilities companies have problems with people sneaking on to the property to steal copper. Prisons need good security around the property. Or it might simply be a way to monitor that the properly credentialed people are coming into a facility, like at a baseball stadium.

When deciding on the right type of perimeter and access security, the primary consideration is to understand what the fence or other barrier is meant to do. Is the fence keeping something out of an area or is it keeping something in?

Once that’s determined, says Chris Herold with Ameristar Fence Products of Tulsa, Okla., the next step is to determine what the threat is because that will determine the type of products needed. Someone whose biggest concern is neighborhood kids climbing the fence will look into a very different type of barrier system than someone who operates a chemical company and wants to keep trucks from crashing into the building.

Other questions that Herold recommends asking before installing any type of fencing include the following:

•  Can the fence be integrated with other physical security technologies and access control devices?

•  What image do you want the fencing to portray?  Do you want the facility to look like prison grounds or should the fencing blend into the neighborhood?

•  What is the reputation of the manufacturer?

•  What are the results of industry testing for the product you are considering?

These were among the issues that Mark Kennaugh, operations manager at CAPSTAR Commercial Real Estate Services, considered for the perimeter security of a data center in the Dallas, Tex. area. Data centers control network infrastructures and hold millions of pieces of sensitive information. Access to the center needs to be tightly controlled.

“Security was our first concern,” he says. “We wanted to create a barrier around the perimeter around the building, with the fence 75 feet off the road. That allows people to walk around the building on sidewalks but not get close to the building.”

The fence Kennaugh used has three areas of security: the exterior of the fence, which is public; the first interior, which is the zone for visitors to the facility; and the second security zone, which is for employees who then need special access into the building.

This more secure fence was installed to replace a chain-link fence that once surrounded the data center. The current fence, installed in 2005, is strong enough to keep people from getting through it. The security bolts that connect the fence can’t be unfastened to break through the fence.

“We wanted something strong, but was also appealing to the neighborhood and durable,” says Kennaugh.

Fences are made from a variety of different materials, ranging from wood to plastic, but for the highest security fences, steel is the material of choice. Chain link remains a popular option; a mini-mesh design with a smaller than usual diameter can deter those who want to climb the fence. The smaller weaving prevents a potential trespasser from getting a foothold.

One of the greatest challenges in fence installation today is retrofitting the fence structures for the current environment. For example, the anti-ram fencing has certain requirements for footings, but the fences are being installed at facilities that have been in operation for decades with fencing that no longer meets security standards. The old system posts and footings may not work with the new system, and soil conditions around the old system may have deteriorated, making new installation more difficult.

Gates are the weakest part of the fence because that’s the point of access. When deciding on the type of gate to be used, such as a sliding gate versus a rolling gate, the main consideration is how the gate will be used. Will it be opened several thousand times a day or just a few times a month? Environmental conditions of the area also need to be considered. Too much snow and ice can make a roll gate less effective, so a slide gate would be the better consideration.

The complexity of the gate system really depends on the level of security desired, Herold points out. A pedestrian gate used infrequently may be locked with padlocks and chains; whereas, a sliding gate that uses a motorized gate operator locks automatically. Those installing the fence and gate have a lot of control over how people can gain access. Electronic card readers are common to allow easy access for people in vehicles.

When budgets are tight, a good perimeter system can provide 24/7 security and cut down on the need for staff monitoring the property. However, there are situations when even the best barriers need some extra help, like alarm systems, cameras, or sensors.

Greg Briggs, project manager with O’Connell Electric in Victor, N.Y., installs a lot of jail security systems, including a recent fence project around a county jail. He usually uses a perimeter fence detection system, in this case by Senstar. “Usually they are ground-mounted sensors, with different technologies for different levels of securities,” Briggs explains. “The county jail we just did had a cable system installed in razor wire work that was mounted across the roof.”

When recommending a fencing system to his clients, Briggs says his main concern is reliability of the product. “When we turned on the system at the county jail, we were being hit with 30-mile-per-hour winds. The system was not false alarming like the old system.”

The sensor system from Senstar incorporates different styles of sensors that warn you when someone is trying to enter or leave the property without permission. Depending on the style, the sensors can be placed on the fence or underground as an invisible barrier. The sensors can be added to any existing fence, of any material.

What sensors bring to the perimeter protection arena is notification that something is amiss on the property, which is vital at a prison, for example. Are sensors or other security monitoring systems necessary on fences? Again, it all depends on what the fence is meant to do and the level of security required. There is no one-size-fits-all solution for outdoor perimeter security, and it may be good to consider a combination of systems.

While the barriers are meant to keep trespassers out (or criminals in), there are times when an added level of access control is required, most frequently with turnstiles. Anyone who has ever gone to an amusement park or to a sports stadium has experienced the most familiar type of turnstile – three armed, waist high – which is meant to ensure that persons with the right credentials (a ticket, say) are able to enter. This type of turnstile is also popular inside lobbies to control the access into certain areas of a building.

Other options of turnstiles are optical (a cabinet with infrared sensors; if the beams are broken without authorization, an alarm sounds) and full-height that allows only one person at a time to enter. Full-height turnstiles are usually used in exterior situations.

The most effective turnstiles prevent tailgating – two people going through the barrier at the same time on one authorization. The locked entrance, says Mark Borto, CEO and president of Boone Edam, is really the last stand in access control. Even in the most sophisticated barrier and access system, once an entrance is unlocked, the only thing preventing a second person from coming in – with or without authorization – is the first person.

Turnstiles fit into the concept of access control in two ways: they remain locked in the same way a regular door is locked and they eliminate the second person coming in without a struggle. Deciding on the type of turnstile to use follows the same line of thinking for fences – think about the application of the turnstile and what type of access is to be controlled.

All in all, the amount of security is determined by the amount of time one has to react to a breach. The perimeter barriers and access controls onto a property should, then, reflect the level of security desired.