Hostile Vehicle attacks have been very prevalent in the media recently due to attacks such as the Berlin Christmas Market.
Despite this trend, attacks carried out by vehicles carrying explosive devices are still the most common form of attack.
Simple cost effective design steps can be implemented to mitigate building damage against these attacks.
Commonly, a vehicle is driven at speed toward a target, parking close to, or ramming a building before detonation.
Considering an average car is capable of holding 200 kilos of explosives, damage from a van or lorry can be devastating.
The most effective way to mitigate the impact of a vehicle borne IED attack is simple – keep vehicles as far away from buildings as possible.
Keeping vehicles away is much more effective than spending money on thick laminated glass or steel-reinforced concrete building facades. It will also provide a better outcome should an attack occur.
There are two main streams of best practice to protect against these types of attacks:
1. Provide effective Stand off distance and good vehicle access control.
2. Harden the building against any residual impact.
Provide effective stand off distance and good vehicle access control
Preventing vehicles from getting close to buildings requires the creation of physical security barriers.
The CPNI recommends a minimum stand-off distance of 30m away from a building for cars.
Larger vans and lorries require a minimum stand-off distance of 90m due to the potential payload of the larger vehicles
Reduce vehicle approach speed.
Introducing landscape elements and passive barriers designed to managing the flow and movement of traffic around the facility is key.
Landscaping can also help control the speed at which a vehicle can approach a vehicle access control or checkpoint.
Simply combining chicanes with concrete planters to ensure that vehicles maintain a slow speed when approaching a facility.
Prevent vehicles deviating
Ditches or streams can be created as part of the landscape design ensuring that vehicles can’t deviate from the intended road layout.
Locate main car park outside building security perimeter.
Locate a staff and visitor car park outside of the main building security perimeter.
This will limit the number of vehicles that need to get close to the building.
Having full height turnstiles into and out of this area for secure facilities also reduces the risk of people gaining unauthorised pedestrian entry.
The orange dotted line in the diagram below shows the site perimeter, the dark blue area is the car park for all non-essential vehicles to keep them away from the building.
The vehicle control point is located where the blue approach road intersects with the red secure boundary line.
At this point, only vehicles that have a need to be near the building and have been searched are allowed to enter.
This red line is set at least 30m back from the building to reduce the impact of a vehicle outside the red secure boundary line.
Buildings at a checkpoint should self sufficient and include heating, lighting, toilet and basic kitchen facilities to prevent staff having to leave them unattended for periods of time.
These buildings should also be hardened in line with the threat profile as some attackers may choose to detonate the explosive if they are challenged at the vehicle access point.
Space needs to be made available for a rejection lane to allow vehicles that have failed to be cleared for entry to leave the site quickly and efficiently.
We do not want to create queues where people reverse back from the control point or rely on opening the gates to allow a vehicle to manoeuvre.
Once these aspects are covered, this will ensure that only vehicles with a genuine need and that have been searched are able to get close to buildings.
Harden building structure against residual blast from hostile vehicle attacks
Trying to protect a building by hardening it against an initial blast is not only complex, but it is expensive and could put unnecessary strain on the structure and foundations of the building, which could over time lead to issues with the building itself.
Hardening against residual blast is easier and cheaper as the impact will be much lower with effective standoff.
Care should also be taken with the layout of the internal building spaces, and the materials used in partitions and staff desk orientation minimise the risk of injury to staff.
Creation of separate muster points and how the alarm should be raised, these must be different to fire or other emergency alarms as people may need to use different escape routes and move to different muster points.
The United States Federal Emergency Management Agency (FEMA), provides guidance in their document “Integrated Incremental Building Protection” on safe evacuation distances in the event of a vehicle blast attack. It states that a safe evacuation distance should be at least 457m for a small car, and up to 1.1km for a Small Delivery vehicle, these distances are obviously ideal and far in excess of what would be necessary for a fire evacuation.
Also consider invacuation and evacuation strategies and procedures – we may want to invacuate people to another part of the site to keep them safe if evacuation is not practical depending on the site layout and point of attack.
The building should also be designed to provide physically secured, blast hardened escape routes to allow safe egress from site away from the point of attack if instructions to evacuate are given.