In the 1990s, in the United Kingdom, Irish Republican terrorists planned to attack the electricity supply system of London. In February 2006 and June 2007 Islamic terrorists attacked the Golden Mosque at Samarra in Iraq. The primary objective of these attacks was not to kill and maim, but in the first case to damage and disrupt the economy of London and the comfort of its citizens, and in the second case to outrage the Shia citizens of Iraq and thus to provoke sectarian violence.
Effective Homeland Security requires a number of quite different, but interdependent, approaches. The first is to reduce or remove support for terrorism through political and moral means. The second is to make life difficult for potential terrorists through legal and administrative means, for example controls on the supply of explosives and border controls. The third is to catch or thwart the terrorists, if possible before they can act; this is the function of the police and intelligence services. The fourth is to limit the effect of any terrorist attack through protection and mitigation measures, which include both active and passive measures.
All these approaches are needed, no one of them alone is sufficient, but any measure that interferes with the comfort or freedoms of the general public or any innocent section of the public can have serious disadvantages, at best people may lose sympathy with the authorities, at worst alien and totalitarian controls may subvert the very freedoms that they were introduced to maintain.
Passive protection and mitigation measures, although they can never provide a complete solution, are among the most useful that are available. Provided that they are correctly designed and installed, they can provide long term and cheap protection, which does not require any human intervention to be effective, and they do not affect the freedoms of the general public. One may compare road safety measures, the design of crash-worthy cars, safety barriers and the like probably does as much to save lives as the most aggressive policing measures.
In all passive protection, the ideal is to design in the protective measures from the start. Unfortunately terrorist threats were not often foreseen when our predecessors built our national monuments, the buildings we live in, and the infrastructure of services that support our modern economy. In the face of a terrorist threat it is not a sufficient response merely to change the design codes, or to design long term protective measures, which, by their nature will take a long time to implement.
It may be necessary to install protective measures at once. There are two prime requirements: the measures must provide protection or mitigation against the current threat, and they must not make things worse in the event of an even more severe attack. Unfortunately terrorists do not always follow official policy, or even the orders of their own leaders, so the careful planner designs against the current threat, but considers the consequences of worse threats.
Traditionally the quick and straightforward response to an explosive threat was a lot of sandbags. Sandbags are undoubtedly effective, they can be placed quickly, and they do not cause dangerous secondary fragments if they are blown-up. But they are labour intensive, very hard work, and require constant maintenance. In most cases they look temporary, and sometimes they look a mess.
The modern alternative is the Concertainer® unit made by Hesco Bastion. This product is probably already familiar to many readers from news pictures from Iraq or Afghanistan or the Balkans, but it may not be as generally known that the first application of the concept was purely civilian.
The Concertainer units are essentially multi-cellular gabions; the protection they provide comes from the sand or other material that they hold. The beauty of their design is the way in which they unfold from convenient flat packs to form a gabion wall, which can then be filled by machine or by hand. The details have been carefully designed to make construction easy, even with an unfamiliar and untrained workforce.
Since 1993, when Concertainer units were first widely used in the Balkans, the system has been very extensively tested against explosive and ballistic attack, including trials by government organisations in the UK, USA, Canada, and The Netherlands. These trials and associated research were used to quantify the level of protection provided by various configurations protective walls, and the resulting technical information allows engineers and planners to design effective protection quickly and easily.
More recently Concertainer units have been tested against direct vehicle attack, in the UK by the Transport Research Laboratory, and Motor Industry Research Association, and in the USA by the Force Protection Battle Lab of US Air Force and by the Texas Transportation Institute. It is perhaps not surprising that a system capable of protecting against a nearby car or truck-bomb should have good resistance against a ramming vehicle.
The prime roles for Concertainer units in Homeland Security are firstly as a quick and effective protective measure, and secondly in the longer-term protection of infrastructure targets. Concertainer units are particularly suitable for rapid installation because of their simplicity, speed of construction, and very low logistic requirements. No specially skilled tradesmen are needed and no unusual or scarce tools or materials are needed.
Although only an enthusiast would claim that a gabion wall is a thing of beauty, its solid and professional appearance warns the potential terrorist that effective protective measures are in place, this may be sufficient to deter the half-hearted terrorist. When the gabion wall is no longer needed, either because the threat no longer exists, or because longer term protection has been provided, then removal of the units is fairly straightforward, the main bulk is in the gabion filling which can be removed and recycled almost as easily as it was placed.
Any well developed infrastructure contains innumerable vulnerable points, that are potential terrorist targets. Electrical supply systems contain transformers and switchgear, water supply systems contain pumps and valves. In many cases protection is not a practical proposition, and it is the redundancy designed into the systems that is their main protection against an isolated attack.
But some vulnerable points are obvious terrorist targets, perhaps because their location close to a road would make an attack easy. In such cases simple physical protection may make what would have been an easy attack impractical. A protective gabion wall may be the solution. In such cases there may be no reason to seek a more permanent design.
It is cheap and easy to extend the life of a gabion wall almost indefinitely by applying a cement slurry or other suitable coating. In many situations the thought of vegetation growing over and out of a protective wall might be unwelcome, but in some circumstances it might be appropriate to encourage this. On remote sites the protective wall might, in time, be swallowed up in a protective hedge. The main advantages of using Concertainer gabions in Homeland Security are found in the ease, and speed with which protection can be put in place.
No highly specialist engineering knowledge or construction skills are needed. Although no permanent protective scheme should be designed without experienced professional advice, nevertheless, in an emergency, any intelligent person can, with the help of the technical information provided by HESCO Bastion can plan an effective, if not optimum, gabion protective wall, and get it built with a workforce without prior training or experience. In the author's experience it is not even essential for the workers and the engineer to have a common language (but it helps).
Obviously a workforce with some training and experience are likely to produce a better result, and to produce it much more quickly. It is not suggested that Concertainer structures should be designed and built by completely inexperienced staff. However, in an emergency, it is a very great advantage to have a system that can be constructed successfully by completely inexperienced staff. This advantage is shared by sandbags - but they are labour intensive, less effective, and hard work.
Passive physical protection is an essential part of most security plans, but it is very seldom the only protection that is needed. The planning and designing of protective measures must not be done in isolation, but should be coordinated.
The size of protective wall needed to protect against a vehicle bomb will depend, among other things, on how close the vehicle can get to the wall, thus it is not just the size of the bomb that is important, but the physical traffic control measures that keep the vehicle away from its target.