How to Choose the Right HVM Solution for a Site

Start with the vehicle threat

The first question when choosing HVM should be: What vehicle threat needs to be mitigated?

The potential attack vehicle needs to be considered in terms of its:

• Vehicle type
• Mass
• Speed
• Approach direction
• Impact angle
• Available approach distance
• Potential attack routes

These characteristics directly influence the level of protection required.

A lightweight vehicle travelling at low speed presents a very different engineering challenge from a heavy goods vehicle travelling at speed. Consequently, an HVM barrier should not be selected simply because it is described as "impact rated". The threat assessment should establish the realistic vehicle scenario that the barrier needs to withstand.

Establish what needs protecting

The next step is to identify the assets and areas that could be affected by a hostile vehicle.

Depending on the site, this could include:

• Pedestrian areas
• Building entrances
• Public spaces
• Critical infrastructure
• Operational areas
• High-value assets
• Vehicle and pedestrian routes

The aim is not necessarily to prevent every vehicle from entering the site. Instead, the HVM strategy should establish where vehicle access creates an unacceptable risk and where physical protection is required. This can affect the type of solution selected.

For example, one part of a site may require a permanent passive barrier, while another may need controlled vehicle access. In these situations, different HVM measures can be combined to create a continuous protective strategy.

Understand the site conditions

The physical characteristics of the site are just as important as the threat assessment.

Before selecting a barrier, consider:

Ground conditions

Investigate what lies beneath the proposed barrier location. This may include concrete slabs, asphalt, existing foundations, drainage systems, utilities and other buried services. Foundation requirements vary considerably between HVM systems. Some require significant excavation and reinforced foundations, while others are designed for shallow installation.

Available space

Consider the footprint of both the barrier and its foundation. This is particularly important where protection needs to be installed close to buildings, roads, pedestrian routes or underground services.

Site geometry

Consider how vehicles could approach the protective line. Road layouts, parking areas, junctions, corners and changes in direction can all affect how an HVM system needs to be positioned.

PAS 68 identifies factors including site topography, architectural constraints, foundations, buried services, available space and traffic management when selecting and applying Vehicle Security Barriers.

Determine the required impact performance

One of the most important stages in selecting HVM is establishing the required impact performance.

PAS 68 and ISO 22343 provides requirements and an impact test method for Vehicle Security Barriers. Testing considers factors including the test vehicle, vehicle mass, impact speed and resulting penetration distance.

When reviewing an HVM specification, it is therefore important to look beyond a simple statement such as "impact tested". Instead, ask: What vehicle was used? At what speed? And how far did it penetrate?

A performance designation provides significantly more useful information than a generic claim of impact resistance.

The barrier should be selected according to the assessed threat. Choosing the highest-rated solution available is not automatically the best approach: over-specification can increase cost, foundation requirements and visual impact, while under-specification may fail to provide adequate protection.

Consider penetration distance

Stopping a vehicle is only one part of HVM performance. The penetration distance after impact is also important.

A barrier may stop a vehicle but still allow part of it to pass beyond the intended security line. If people, buildings or critical assets are located immediately behind the barrier, this residual penetration could still present a significant risk.

The required penetration performance should therefore be considered alongside the impact rating. The objective is to create an appropriate stand-off distance between the potential vehicle impact and the asset being protected wherever the site allows.

HVM Bollards

Impact-rated bollards provide a compact way of creating a protective line while allowing pedestrian movement between individual units. They can be suitable where space is limited or where the appearance of conventional heavy barriers is undesirable.

HVM Blocks

Concrete HVM blocks provide a passive physical barrier that can be appropriate where there is sufficient space for a larger footprint. Their weight provides a physical obstacle, while their passive nature means they do not rely on power or an operator.

HVM Planters

HVM planters can integrate vehicle mitigation into landscaping and public realm schemes. They can provide a more visually integrated alternative to conventional security infrastructure while still incorporating an engineered, impact-rated barrier system.

Consider installation and foundations

An HVM barrier can only achieve its intended performance when correctly installed. The barrier, foundation and surrounding ground should therefore be considered as a complete system.

Installation requirements may include:

• Foundation dimensions
• Concrete specification
• Reinforcement
• Anchorage
• Excavation depth
• Ground conditions
• Drainage
• Buried services
• Existing structures
• Finished surface levels

This is especially important for shallow-mount HVM systems. Reduced excavation can be advantageous where underground services, existing structures or restricted ground conditions make deep foundations difficult. However, shallow installation does not mean reduced performance; the complete system still needs to be appropriately engineered and tested.

Always check that the proposed installation matches the configuration used during testing.

A simple HVM selection process

The process can be summarised into ten questions:

1. What is the vehicle threat?
Identify the vehicle type, mass, speed and approach conditions.

2. What needs protecting?
Identify people, buildings, infrastructure and other critical assets.

3. Where is protection required?
Map potential vehicle routes and establish the security line.

4. What impact performance is required?
Determine the appropriate vehicle, speed and penetration criteria.

5. What are the ground conditions?
Check foundations, excavation requirements and buried services.

6. How does the site need to operate?
Determine vehicle access, emergency access and operational requirements.

7. Which barrier type is appropriate?
Compare bollards, blocks, planters and active systems against the established requirements.

8. Can it be installed correctly?
Check foundations, spacing, interfaces and installation details.

9. Does it work with the surrounding environment?
Consider accessibility, appearance, landscaping and everyday use.

10. Can the performance be evidenced?
Verify the test standard, test configuration and installation requirements.

Choosing the right HVM solution

There is no single HVM solution that is suitable for every site.

The right choice is the one that provides an appropriate level of tested protection while working with the site's physical, operational and environmental requirements.

Impact-rated bollards, HVM blocks and security planters can all form part of an effective strategy, but their suitability depends on the threat assessment, required performance, installation conditions and intended use.

Ultimately, choosing HVM should be a risk-led process. Understand the threat first, establish what needs protecting, assess the site constraints and then select a tested Vehicle Security Barrier that meets the required performance.

This approach helps create an HVM strategy that is proportionate, technically defensible and practical to install and maintain.

Ready to talk through your HVM options in more detail? Contact our team today.