EXCLUSIVE: Perimeter security in urban environments

Urban environment - perimeter security

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Thomas Vonier, CPP, Architect and Senior Partner at Chesapeake Strategies Ltd explores how to reinforce boundaries in towns and cities.

Perimeter security

As key elements in any comprehensive approach to security, perimeter controls can pose a dilemma; typically, they are the first thing encountered by visitors to a building, leading owners to say: “Make them attractive and friendly-looking… but make sure they work.”

Facility managers and security professionals naturally tend to concentrate on perimeter barriers and access controls for a sole property or building, which have relatively small peripheries.

We’ve all experienced these secure enclaves – government offices, police stations, court buildings – where people seeking entry are subject to physical search and inspection of credentials.

Usually there is just one public entrance, staffed by uniformed guards and equipped with X-ray machines and magnetometers – the checkpoint approach.

Less common but growing in favor are urban control zones, where the realm of surveillance and control is much wider, often encompassing multiple buildings, streets, sidewalks and public spaces.

These zones are being implemented in museum precincts, business districts, government centers and major urban tourist areas.

Marking the boundaries

An early example is the City of London’s “Ring of Steel”, a secure perimeter around one of the world’s most important financial districts, which was hit by a massive truck bomb in 1993.

Access to this large urban area is limited by an extensive, mostly unobtrusive set of controls around its periphery.

Its objective is to minimize the number of authorized entry points, to provide strong barriers and reliable alarms against breach and to ease the work of those who must examine the people and vehicles entering the area.

Another example is the grounds surrounding the White House in Washington DC.

An important national symbol with distinctive architecture, the White House is a prime target for demonstrators, violent extremists and individuals seeking to cause disruption.

Its surrounding security features are compatible with its historic character yet provide a perimeter capable of thwarting modern threats.

The executive mansion security perimeter includes Lafayette Square to the north and the Ellipse to the south. Vehicle barriers (some retractable) have long been a part of the landscape and are all guarded by well-armed officers of the uniformed division of the US Secret Service.

Bollards, barriers and operable gates to the White House lawns are designed to the highest standards of vehicle-stopping power.

Private motor vehicles and trucks cannot approach the grounds and Pennsylvania Avenue itself has been closed to traffic for decades.

A tall cast-iron fence (and more recently, a ten-foot “no-go zone” adjacent to the public side of that fence) controls access to the north and south lawns.

These are obvious, visible measures, clearly delineating the boundary between “inside” and “outside”.

In contrast, however, the large open square and parklands around the White House are open to the public and accessible without search or challenge.

These areas have subtle physical design and planning features that are much less apparent than vehicle-stopping and anti-breach measures.

These less visible steps enhance natural surveillance, ease foot and bicycle patrol duties and increase the visibility of pedestrians in the area.

Every entry point to Lafayette Square is watched; officers stationed at fixed posts can assess an individual’s comportment, the appropriateness of a person’s clothing (which can be used to conceal weapons) and the nature of any parcels or objects being carried.

The area is also patrolled by officers on foot and bicycle. Landscaping designs ensure that there are no places to hide or evade detection.

To the south, stone seating ledges and benches are being installed along the edge of the Ellipse, thus preventing breaches from automobiles simply using landscape features, as has been done around the Washington Monument.

The dynamics of perimeters

Our urban infrastructure – streets, squares, sidewalks, footpaths, bridges, parks, alleys and transit hubs, the gathering spots we use every day – is now the front line in the fight against violent extremism and crime.

The urban control zones in London and Washington DC show how architecture and design can make it easier – and even natural – for the responsible authorities to monitor comings and goings, to assess behavior and intentions, to challenge intruders and to sound alerts.

Similar control zone measures are being proposed for the Wall Street district in New York City and for areas in other cities.

However, some areas are more easily secured than others. Significant differences exist between a medieval European city, laid out for the very purpose of security and a Midwestern US town, plotted in the late 20th century to facilitate movement and commerce.

That is one reason US cities have been slower than their European counterparts to implement control zones.

The objectives for perimeter security in urban settings are simple: limit pedestrian and vehicle access to natural portals, where trained personnel can scrutinize them; use all available means to monitor the environment, including “smart” video surveillance systems; and poise trained forces nearby, ready to intervene when needed.

Security dynamics can change quickly, favoring equipment and systems that are lightweight and flexible – adaptability and quick response are especially important for crowd control in episodes of civil unrest and during major public events.

Although metal barricades and other light obstacles may work as boundary markers and crowd-stoppers, they are not effective vehicle barriers.

Substantial installations are needed to stop moving motor vehicles. As acceleration and mass increase, so does force. The need is to slow all vehicles and to prevent the heaviest ones from gaining access.

Barriers that stop cars will not necessarily stop trucks. Arresting a speeding truck requires much heavier obstacles. 

We know how to counter such threats for military installations and other facilities that face risks of vehicle attack, but as we deploy such countermeasures in the civilian realm, they need to be made unobtrusive and attractive.

Security oriented street furnishings present a good opportunity to channel movements and prevent breaches.

Outdoor furnishing manufacturers all over the world now offer flexible “hardened” products and landmark projects and studies have shown creative ways to use typical streetscape elements in perimeter security plans.

Augmented security

People seeking to enter many establishments today are asked to state their business, present identification, show evidence of a reason to enter and submit to a physical search of person and belongings.

Extending perimeter security screening and monitoring to larger urban areas offers a way to make security faster, less costly and less intrusive.

At times it is desirable to have highly visible security provisions; evidence that a given area or facility is closely watched and carefully guarded may deter and deflect.

Such steps will not defeat determined attackers, but they can facilitate pre-event security preparations and ongoing monitoring to spot suspicious or alerting behaviors.

Architecture and urban design won’t thwart well-armed attackers who are willing to die while harming others, but design can control access, create natural opportunities for surveillance and ease (or even augment) the role of security personnel.

As we invest in measures to anticipate threats and reduce vulnerabilities, we must also try to make them beautiful.

About the author

Architect Thomas Vonier, FAIA RIBA, CPP is a Senior Partner in Chesapeake Strategies Ltd, based in Paris and Washington DC.

He leads the firm’s work to improve security in cities and for organizations operating in high-threat regions.

He led landmark reforms in embassy design implemented by the US Secretary of State and was the foreign operations security advisor for Halliburton.

Thomas was elected President of the International Union of Architects (UIA), representing the world’s 3.2 million architects and National President of the 96,000-member American Institute of Architects (AIA).

He belongs to ASIS International and holds board certification as a security professional.

This article was originally published in the November edition of Security Journal Americas. To read your FREE digital edition, click here.

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