In city centres with pedestrianised areas, narrow alleyways or busy roads, perimeter security differs fundamentally from that of a traditional industrial site. The area to be secured is simultaneously a living environment, a place to spend time, a business hub and a traffic area. Delivery traffic, emergency services, cleaning, markets and events must still be possible. “A security concept that fails to take these processes into account will quickly be circumvented in everyday life or left permanently open,” warns Francis Seijas, Managing Director of Consel Group / Consel Deutschland GmbH, specialists in access control. “It then loses its effectiveness – regardless of how effective the barriers used are.”
At the same time, consideration must be given to accessibility, tactile guidance, pedestrian and cycle traffic, escape and rescue routes, sightlines, lighting, cleaning and winter maintenance, drainage, and the avoidance of trip hazards. “The safety barrier should, as far as possible, be a natural part of the open space and not appear to be a safety installation that has been added as an afterthought,” emphasises Seijas.
That is why planning in urban areas does not begin with the selection of a specific safety installation. Rather, the process starts with the safety objective, the risk assessment and a careful site analysis.
Integrating collision protection into urban design
If, for example, the aim is to prevent attacks or intrusions involving vehicles, several factors must be assessed for each relevant access route. These include the type and mass of the vehicle, the achievable speed, the angle of impact and the maximum permissible penetration depth.
On this basis, the protective function can then be incorporated into the urban design. “Green, stone-filled wire baskets or benches with concrete bases and wooden seats do not look much like vehicle impact protection,” explains Frank Sperling, security consultant at VZM (Von Zur Mühlen’sche GmbH). According to him, even solid litter bins firmly anchored to the ground can be considered as discreetly designed protective elements. As an example, he cites the 50Hertz headquarters at Berlin Central Station, where the safety measures blend almost imperceptibly into the surroundings.
The geometry of the site also plays an important role here. Tight bends, changes in level or short acceleration distances can reduce the speed that can be reached and thus the impact energy. “Access roads should be designed in such a way that vehicles cannot travel in a straight line towards buildings, but are forced to slow down by changes in direction,” says Sperling.
When heritage protection is factored into the planning
In new-build areas and greenfield projects, perimeter protection can usually be incorporated into the overall concept at an early stage. Planning is considerably more challenging in established city centres and historic quarters with listed buildings. Old courthouses, banks housed in historic buildings or centuries-old town halls characterise the cityscape and continue to fulfil important functions. Their protection must therefore meet both modern security requirements and the need to preserve their historic character. Nuremberg provides an excellent example of how perimeter security and heritage protection can be planned together.
“It is precisely the historic parts of the city that generally have a higher concentration of buildings of supra-regional significance. These buildings are therefore the focus of public interest, but at the same time this also means they face a greater risk of damage,” says Dr Marco Popp, Head of the Local Heritage Protection Authority in Nuremberg. At the same time, Nuremberg’s historic old town as a whole constitutes a valuable cultural heritage in need of protection. It is essential to preserve this and safeguard it from negative influences.
This gives rise to different solutions depending on the use of the space.
According to Dr Popp, temporary installations are often sufficient for open spaces where events requiring security measures take place only occasionally. Sensitive properties, on the other hand, can usually be secured through discreet modifications that are coordinated in terms of both building design and heritage conservation. These can be carried out on façades as well as indoors. “Examples include burglar-proof windows and doors, right through to surveillance systems in and around particularly sensitive areas,” says Popp. The aim is to integrate security-related technology and equipment as discreetly as possible, so as to impair the building’s appearance as little as possible.
Discreetly securing historic façades
Particularly in the case of historic façades, this unobtrusive integration can require more complex technology, as Frank Sperling of VZM explains: “Although conspicuous cameras for façade surveillance are cheaper, they often cannot be installed for aesthetic or heritage conservation reasons.” One alternative is concealed systems that use laser grids, although these incur higher costs.
Similar requirements apply to historic windows and doors. Preserving them can make it more difficult to implement burglary protection. “This limits the resistance class that can be achieved, meaning that additional, costly protective measures may be required,” says Sperling. He therefore recommends incorporating security requirements into architectural and outdoor space planning at an early stage. “Security by Design means thinking about security right from the start. Even façades with resistance class RC3 can be designed to be architecturally appealing.”
A jewellery shop on Nuremberg’s Kaiserstrasse demonstrates how this can be achieved. During the shop’s refurbishment, special glazing and façade elements were installed to prevent motor vehicles from crashing through the shop front. “Despite the heightened security requirements, the design is attractive and in keeping with the surrounding area. The façade’s enhanced protective function is not immediately apparent,” emphasises Dr Popp.
Adapting security concepts to the existing building fabric
Where structural or technical measures require intervention in the historic fabric, staffing solutions may be more appropriate. “A historic gate leading to a city palace cannot simply be drilled into to lay cabling. An alternative could be a combination of CCTV surveillance and a security service,” says Sperling.
This is precisely why Francis Seijas emphasises the importance of early collaboration between all relevant disciplines – from heritage conservation and architecture, through landscape architecture and civil engineering, to safety planning. “Sampling in real-world lighting and material contexts also helps with coordination. Reversible interventions can offer advantages in this regard, but they are no substitute for project-specific heritage conservation and safety assessments,” says Seijas.
According to Dr Popp, the Nazi Party Rally Grounds in Nuremberg demonstrate what reversible solutions look like in practice. Due to the historical background and the monumental nature of the buildings, mobile standard concrete barriers are used in some areas there as vehicle impact protection. Mobile protective barriers are also used at inner-city events such as the Bardentreffen. As they are only erected for a short period, they do not require any special consultation with heritage conservation experts. In some cases, they are deliberately designed in understated colours.
Reversible systems are also advantageous in situations where underground work would be problematic, such as near archaeological monuments or sites suspected of containing archaeological remains. In Nuremberg, such measures are stipulated as conditions in the planning permission process under heritage protection legislation. Archaeological supervision is required during excavation work. “If archaeological features are uncovered in the process, these must be documented and the finds recovered,” explains Dr Popp.
The subsoil determines the planning process
It is not only in historic areas, but also in more modern urban neighbourhoods that the subsoil determines the planning process. Beneath roads and squares lie underground car parks, sewers, cellars and utility pipes. Consel therefore begins by analysing utility plans, locating existing pipes and, where necessary, investigating the ground using ground-penetrating radar or test trenches. In addition, tests are carried out on the building ground, groundwater, drainage and frost depth. “In the case of underground car park ceilings, underpasses or historic vaults, it is also necessary to assess at an early stage just how load-bearing the existing structure actually is,” explains Seijas. A common planning error, he says, is to select a product first and only then investigate the subsoil. Consel takes the opposite approach: first, the local conditions are clarified, and then the appropriate protection system is determined.
This approach is particularly evident in the case of underground car park ceilings. Here, it is necessary to assess whether the existing structure can withstand dynamic impact loads. Possible solutions include load-distributing frames, anchoring to load-bearing structural elements, localised reinforcements or repositioning the protection line. Waterproofing, drainage, corrosion protection and access for maintenance must also be taken into account at the detailed design stage.
Effective perimeter protection in city centres begins with a comprehensive understanding of the location – from everyday uses and the historic built environment to the subsoil. If these factors are taken into account at an early stage, the result is solutions that work in everyday life, provide reliable protection and, at the same time, preserve the character of the city.
