How High Should Hostile Vehicle Mitigation Fencing Be?
When specifying your high-security fence, deciding on design features such as height can be tricky.
One area that demands attention is the mitigation of hostile vehicle attacks.
When specifying hostile vehicle mitigation products that offer crash-impact protection, such as fencing, there are many questions you need may answering.
In this blog we are focusing on just one – how high should hostile vehicle mitigation fencing be?
While there’s no one-size-fits-all answer, there are some key factors to consider when specifying your HVM fencing height.
A Recap: Understanding Hostile Vehicle Mitigation Fencing
Hostile vehicle mitigation refers to the implementation of physical security measures designed to prevent or minimise the impact of vehicle-borne attacks.
The goal is to deter, delay, or completely prevent hostile vehicles from gaining access to sensitive or vulnerable locations, protecting people, property and reputations.
There are several types of hostile vehicle mitigation measures available. These measures include:
- Barriers
- Bollards
- Gates
- Security Fences
When specifying security fencing, there are some design criteria that you will want to ensure are correct. One of your main considerations is… how high does my fence need to be?
We have named the main factors that come into play when specifying a HVM security fence.
Vehicle Type
Depending on the location of your site, the type of vehicle that could crash into your premises might differ.
As hostile vehicle mitigation products are designed to stop or deter the most common types of vehicles used in attacks, make sure to consider what type of vehicle you’d expect to see near your site. Furthermore, accidental crashes are more common than you might realise. Accidental crashes caused by vehicle fault or medical issues need to be considered when specifying your fence.
Different vehicles have varying sizes, weights, and capabilities. Therefore, consideration should be given to common vehicle types used in attacks, such as cars, trucks, or larger commercial vehicles.
Vehicle Impact Speed
The speed at which a hostile vehicle may approach the area is another critical factor.
For example, StronGuard fencing has only been tested to stop a 7.5 tonne vehicle at 30mph. If you are located where the vehicle can get up to higher speeds, other solutions will need to be found.
Higher impact speeds require stronger and taller fencing with larger foundations to effectively mitigate the threat. The fence should be designed to withstand the force of an impact from a vehicle traveling at a significant speed.
Top tip: when considering the speed at which vehicles can attack, make sure to assess the location of your premises. Are there any run-ups to your site? If your site is in a location that would prevent a vehicle to gain considerable speeds, a shorter fence would suffice.
We always recommend getting a professional to complete a Vehicle Dynamic Assessment (VDA).
It is advisable for all fencing contractors and specifiers to carry out wind load calculations to determine the foundations for the fence structure.
Design Intent
Clarifying the objectives and desired purpose of the fence design, in turn, influences its height and strength requirements.
Crash rated fencing is often a preferred solution if the site needs to be protected from both vehicle impact and to stop trespassers.
The minimum height for crash rated fencing is 1.8m high. However, if you are trying to deter trespassers, you may want to opt for a taller fence.
Also, if your crash rated fence needs to also be accredited to LPS 1175 A1 or LPS 1175 B3, there are also minimum heights to meet their standards. For example, the minimum height for LPS 1175 B3 fencing is 2metres.
And as mentioned before, the height of a fence and the addition of anti-climb fence toppings are the best features to make a fence difficult to climb.
Ultimately, the fence’s height should be compatible with the overall visual appeal of the area while maintaining its primary function as a vehicle mitigating barrier.
Safety Standards And Regulations
In the UK, a fence over the height of 2 metres will require planning permission.
Compliance with safety standards ensures that the fence is designed, installed, and maintained in a manner that prioritises safety, effectiveness, and legal requirements.
For example, vehicle mitigating fence systems undergo physical crash testing to assess their performance under realistic impact scenarios.
For example, fencing such as StronGuard™ RCS is tested to stop a 7.5t vehicle at 30mph (48kph).
Expert Advice
Specifying the height of a vehicle mitigating fence requires careful consideration of factors such as design intent, risk assessments, safety standards, and expert consultation.
By considering these factors, a well-designed and properly specified fence can enhance security, protect assets, and mitigate potential threats from hostile vehicles.
Barkers Fencing’s experts work closely with you during the specification process to discuss the right fencing products for you. This includes specifying height, discussing accreditations, design elements and all other concerns you might have for your fence installation.
Please get in touch with us at Barkers Fencing to discuss fence height and other elements of specifying your security fence today.