DIN VDE V 0826-20 focuses on the security performance of the overall system and establishes a practical framework for the planning, installation, operation and evaluation of perimeter security systems

Fence sensors, video technology, radar and other detection systems can detect intrusion attempts at an early stage. However, a high-performance individual component does not in itself constitute a functioning perimeter security system. The decisive factors are which threats are to be detected in the first place, how reliably this can be achieved under real-world conditions, how an incident is assessed – and what response follows.

This is precisely where DIN VDE V 0826-20 “Surveillance systems – Part 20: External Perimeter Security Systems – Rules of Application’. Published in September 2023, this draft standard supplements the European Technical Specification CLC/TS 50661-1 and translates its fundamental system concepts into concrete rules for planning, design, installation, commissioning, operation and maintenance.

This simultaneously shifts the perspective on perimeter security: the question of which product is to be installed is no longer the starting point of a project. The decisive factor is, first and foremost, the level of protection a system is intended to achieve under the relevant spatial, operational and security-related conditions.

The underlying CLC/TS 50661-1 sets out general requirements for perimeter security systems, irrespective of the specific field of application – ranging from critical infrastructure and industrial facilities to other commercial or private properties. The aim is to detect attempts at tampering and intrusion in the external areas of buildings or properties. The specification utilises, amongst other things, four levels of self-protection, four environmental classes and four performance categories.

The crucial question is: what is the system expected to achieve?

In practice, perimeter security often begins with a technical question: which sensors are suitable for a fence? Where should cameras be positioned? What range does a detection system require?

Strictly speaking, the order should be the other way round.

First, it must be clarified what the risk is and which scenario needs to be managed. Is the aim to detect unauthorised access at an early stage? Does tampering at the property boundary need to be detected? How quickly must an alarm be processed? Which areas have different security requirements? And what should happen if a security-related incident is actually detected?

Only then can one determine which technical solution is appropriate.

CLC/TS 50661-1 provides a systematic framework for this. Among other things, it regulates and specifies the classification of a perimeter security system according to its inherent security level and performance category, types of power supply, as well as area and shift models. Added to this are protection levels, operating modes and alarm levels. Of particular importance here is the functional description of the overall system, rather than defining security performance solely in terms of separate system components.

Whilst this may initially appear to be a technical and normative matter, it has direct practical implications.

This is because a system can function flawlessly from a technical perspective and yet still fail to achieve the actual security objective. A detector may correctly register movement – but if this regularly results in irrelevant alarms, if a control centre cannot unambiguously classify the event, or if no defined intervention follows, the security benefit remains limited.

Perimeter security is therefore not merely a collection of individual devices. It is a process chain.

Detection alone does not guarantee security

The logical structure of a perimeter security system, as outlined in the BHE information, demonstrates how consistently this family of standards pursues this concept.

Detectors supply events and metadata to a central processing function. Manual inputs can also be incorporated. Within the processing stage, factors such as the configured system structure, acknowledgement rules, security levels and an event log play a role. The processed information, in turn, gives rise to defined alarm levels. These can be forwarded to external interfaces, internal monitoring stations or actuators and signal transmitters.

The model highlights an important distinction between detection and the actual security effect.

An intrusion attempt must first be detected. The system must then assess whether a security-relevant event has actually occurred. Subsequently, the information must reach the correct destination. And finally, an appropriate response is required.

If any one of these links fails, even the best sensor technology loses some of its effectiveness.

This is precisely why interfaces are becoming a central component of perimeter security. In modern security architectures, fence sensors, video technology, access control, hazard management systems and control centre technology are increasingly interconnected. For example, an event detected at the perimeter can activate a camera, trigger additional verification or automatically forward information to a control centre.

The quality of a system is therefore increasingly determined by how well these functions work together.

DIN VDE V 0826-20 puts system requirements into practice

CLC/TS 50661-1 forms the overarching framework. For specific projects, however, a system standard alone is not sufficient. Installers, planners and operators must develop a functioning security solution for a specific site based on abstract requirements.

DIN VDE V 0826-20 arose from this need. According to the BHE, it was developed within the DKE with the involvement of delegates from the BHE’s Perimeter Technical Committee. It is intended to supplement the existing system standard with specific application rules.

In doing so, it pursues three key objectives.

Firstly, installers and users are to be provided with a framework enabling them to clearly define their requirements for a perimeter security system in the first place. Planners and operators should then be able to select suitable solutions for specific scenarios and the associated risks. Finally, the standard is also intended to support the use of the system during operation in such a way that the specified requirements continue to be met on a permanent basis.

The first point in particular is crucial.

This is because even high-quality technology cannot compensate for unclear requirements. What is meant by ‘reliable perimeter surveillance’, for example, can vary considerably between operators, planners and installers. One may expect comprehensive detection of every approach, whilst another may only expect an alarm to be triggered when a property boundary is actually breached.

The earlier such requirements are defined in a measurable and transparent manner, the lower the risk that a completed system will function technically but fail to meet the operator’s expectations.

Risk assessment must precede product selection

This approach becomes particularly clear when dealing with different types of protected sites.

A logistics centre on the edge of an industrial estate places different demands on perimeter security than a power station, a data centre or a sprawling industrial site. The terrain, vegetation, access routes, lighting, operational movements and adjacent public areas all influence the planning, as does the nature of potential attacks.

Environmental conditions must also be taken into account. Rain, snow, wind, animals or vegetation can affect detection systems and must be factored in at the planning stage.

The key question cannot therefore be: Which technology is the best?

It must be: Which technology delivers the required performance in this specific scenario?

This also gives the issue of false alarms a different significance. In theory, a system can be set to be particularly sensitive and detect almost any change. However, if this results in the control centre being constantly bombarded with irrelevant events, the technical sensitivity can actually have a negative impact on the entire security organisation.

Performance therefore does not mean maximum detection at any cost, but rather a security performance that is appropriate to the risk, manageable and reliable.

Critical infrastructure raises the bar

This concept is particularly relevant in the case of critical infrastructure and other highly sensitive sites.

Here, an intrusion can have far-reaching consequences beyond immediate property damage. If key technical facilities are tampered with or operational processes disrupted, this can affect production, supply or other critical functions.

In such security concepts, the perimeter often forms one of the first lines of defence.

Its role is not necessarily to stop an attacker solely by technical means. It is at least as important to detect an incident as early as possible, thereby gaining time for verification, situation assessment and intervention.

It is precisely at this point that the importance of a coordinated layered model becomes apparent. The earlier a security-related incident is detected, the greater the scope for action before a particularly sensitive internal area is reached.

However, this only works if detection, alarm processing and organisational response are planned jointly.

A sensor on the fence cannot replace a security strategy.

Planning does not end with commissioning

Another key aspect of DIN VDE V 0826-20 is therefore its focus on the entire life cycle of a system.

The application rules include guidance on planning, design, installation, commissioning and maintenance. In doing so, they take into account both similarities and differences compared with other security systems covered by DIN VDE 0833.

The fact that maintenance is explicitly part of the overall concept is more than just a technical formality.

Outdoor installations change.

Vegetation grows and can affect detection zones. Buildings or access routes are altered. Additional installations are added. The use of areas of land changes. Lighting conditions change. Even the threat scenario on the basis of which a security concept was originally developed may shift.

Consequently, a system that was effective at the time of commissioning is not automatically guaranteed to remain effective in the long term.

For operators, this means that the question of whether the system is functioning must not be answered solely on the basis of technical availability. The decisive factor is whether it continues to achieve the security performance originally defined.

Performance must be objectively verifiable

This is precisely where one of the most significant aspects of the application rules lies.

DIN VDE V 0826-20 provides methods and tools for the objective assessment of the performance of a perimeter security system. In addition, there are checklists and system descriptions for planning and documenting the processes involved in setting up a PSS. According to the BHE, these documents have been made available separately as cross-association papers.

This helps to address a fundamental problem in many security projects: the difference between technical functionality and actual protective effectiveness.

It is easy to check whether a camera is transmitting images. The same applies to whether a sensor is transmitting signals.

It is considerably more difficult to determine whether, under real-world conditions, the overall system reliably distinguishes between relevant and irrelevant events, forwards information in a timely manner and supports the intended responses.

Objective evaluation criteria create a common basis here between clients, planners, installers and operators.

And they may also change the discussion about quality.

This is because quality in perimeter security can then no longer be determined solely by the technology installed or product features. It must be measured by whether agreed performance requirements are actually met.

From a product-focused approach to a security process

This is precisely where the true significance of DIN VDE V 0826-20 lies.

Perimeter security is often visible through its hardware: fences, cameras, sensors, barriers or access control systems. However, its effectiveness is determined by a less visible part of the overall concept – risk analysis, planning, configuration, alarm handling, interfaces, operational processes and intervention.

The standard thus shifts the focus from the individual security product to the security performance of the system.

For installers, this means not only installing components correctly from a technical point of view, but also implementing the requirements of the overall project in a transparent manner. For planners, it provides a framework within which risks and technical solutions can be linked in a more structured way. Operators, in turn, are given a basis for formulating requirements more clearly and for assessing a system’s performance throughout its lifecycle.

The BHE consequently regards the rules of application as important quality benchmarks and as the basis for the successful planning and implementation of perimeter security projects.

Conclusion: Security must be measured by its effectiveness

The growing diversity of technology opens up numerous possibilities for perimeter security. Intelligent video analysis, networked sensor systems and integrated security platforms can now provide significantly more information than previous stand-alone solutions.

However, more technology does not automatically mean greater security.

The decisive factors remain whether a solution is suited to the actual threat, whether its performance can be defined and verified, and whether a detected threat triggers the correct response in good time.

DIN VDE V 0826-20 provides an important framework for this. It combines the system logic of CLC/TS 50661-1 with the practical requirements for planning, installation and operation, thereby promoting an approach that is becoming increasingly crucial in complex security projects:

Perimeter security does not begin with the selection of a sensor – but with defining what is to be protected, detected and achieved in the event of an emergency.