Assessing security for a perimeter security fence
1. Start with risk, threat, and operational requirements
Begin with a formal risk assessment and an Operational Requirements process. This creates a single auditable statement of what the fence must achieve, who and what it must protect, how long it must delay intrusion, and the response assumptions that underpin those timings. Clear operational requirements prevent nugatory spend; they keep stakeholders aligned.
Translate risks into performance objectives. Define adversary types, capabilities, tools, and behaviours. Set the required delay against credible tools and techniques; define the target detection and response times. These elements drive the specification for fence height, mesh aperture, post spacing, toppings, gates, and integrated detection.
2. Principles for protection from forced entry
Forced entry protection is about buying time. Specify products and assemblies that provide demonstrable delay against manual attack with tools, and ensure that the claimed performance is relevant to the product type and the threat. UK guidance maps common standards to threat levels; it explains selection steps so that requirements are proportionate and applicable to the product category under consideration.
For perimeter elements, LPS 1175 classifications are widely accepted for rating resistance to forced entry by defined tool sets and attack durations. Select the classification that aligns with your response model; be explicit about the attack tools and the minimum delay you need at the fence line and at the gates.
3. Security fences and walls in a layered approach
Perimeter fences and walls form part of a wider protective security system. They work best when combined with clear zones, lighting, natural surveillance, and procedures that support patrols and speedy intervention. Fences should be sited to maximise sightlines; reduce cover for intruders; and avoid features that aid scaling. Terrain, drainage, and foundations must be considered to prevent under or over ground vulnerabilities.
Design the perimeter to channel pedestrian and vehicle movements to controlled points; make hostile reconnaissance more difficult. Opportunities for concealment along approach routes should be removed; blind spots at corners and around buildings should be mitigated with lighting and surveillance.
4. Gates: the most attacked part of any perimeter
Gates dictate real world performance. They must meet the same forced entry objectives as the adjacent fence; they must do so while operating reliably. Specify gate leaves, posts, locking, and foundations that match the required resistance class; then validate that the locking arrangement and any access control hardware do not undermine the structure. Site gates where supervision is strongest, with space for vehicles to queue without compromising the secure line.
Active gates introduce electrical, mechanical, and safety risks. Build in fail secure principles; protect cabling; use tamper evident housings; and define manual override procedures. Maintenance access must not create an exploitable weakness.
5. Integrating Perimeter Intrusion Detection Systems
A fence that only delays is not enough; it must also support detection. Perimeter Intrusion Detection Systems can be barrier mounted, free standing, ground based, or rapidly deployable. Selection should follow the operational requirements, taking account of environment, wildlife, vibration, weather, and potential nuisance alarms. Commissioning must include defined acceptance tests, documentation, and a maintenance schedule.
Integrate detection with lighting and CCTV so that alarms trigger instant verification and response. Place sensors and cameras to avoid occlusion by the fence fabric, gates, vehicles, or landscaping.
6. Selecting standards and evidence of performance
Use recognised standards to anchor specifications and to compare options consistently.
- Forced entry: LPS 1175 classifications provide graded resistance to manual attack with defined tools and time limits. Choose a class that aligns with your site’s response time and attacker profile; be clear about tested configurations and installation details.
- Burglar resistance and related product types: Depending on context and product, BS EN 1627 to 1630, STS 202, and related schemes may be relevant within secure compounds or at building interfaces; ensure applicability to the product category.
- Hostile vehicle mitigation at the perimeter: Where vehicle attack is a credible risk, specify vehicle security barriers to ISO 22343‑1 for impact performance; apply ISO 22343‑2 for installation and operational use. Coordinate barrier design with the fence line and gate approaches.
Where possible, procure equipment from sources that provide transparent evidence of testing and performance ratings; ensure that installation matches the tested configuration to avoid performance loss.
7. Design details that matter at the fence line
- Height and form: Height should reflect the scaling risk and the desired delay. Avoid horizontal rails that create footholds; specify tight mesh apertures that resist climbing and tool insertion where required. Maintain clear zones either side of the fence to expose intruders and ease patrols.
- Toppings and terminations: Where lawful and proportionate, consider toppings to increase delay. Ensure robust terminations at ends, corners, and around culverts or changes in level; these are common attack points.
- Groundworks and drainage: Detail foundations and anti dig measures to suit soil, frost, and water conditions. Prevent erosion or settlement that could open gaps under panels or posts.
- Services and cable protection: Route detection and access control cabling in protected conduits. Avoid exposed junctions at low level. Document routes for maintenance and incident recovery.
8. People, procedures, and hostile reconnaissance
Perimeter measures succeed when paired with trained people and good procedures. Staff must understand alarm handling, incident escalation, and patrol routes. The perimeter should be designed to frustrate hostile reconnaissance; deny easy observation points; reduce predictable routines; and ensure that suspicious behaviour can be noticed and acted upon.
9. Assurance, installation, and maintenance
Performance on paper is not enough. Insist on installation to the tested detail; witness key stages; keep records of torque settings, fixings, foundations, and cable terminations. Commissioning should verify both delay features and detection functions. Build a preventive maintenance plan that covers fence fabric, gates and operators, sensors, power supplies, and software updates.
10. Bringing it all together: a practical checklist
- Define the operational requirements; capture threats, response, delay targets, and integration needs.
- Select applicable standards; use LPS 1175 for forced entry at the fence and gate line; apply ISO 22343 for vehicle barriers where relevant.
- Design the perimeter as a system; align fence, gates, clear zones, lighting, CCTV, and detection.
- Specify critical details; heights, mesh, posts, toppings, foundations, service protection, and gate locking.
- Assure supply and installation; require evidence of testing and install to the tested configuration.
- Commission and maintain; test detection and delay performance against your operational requirements; maintain to preserve assurance over life.
Final thoughts
A perimeter security fence is a purposeful delay and detection platform, not a decorative boundary. When you anchor requirements in risk, select proven standards, and treat the fence, gates, and detection as one integrated system, you turn the outer edge of your site into time and information that your responders can use.
You may also be interested in our blog 'Is security rated worth the paper it is written on'
