[via US Dept of State] The Department of State’s physical security concept is to create a tiered defensive system which consists of both active and passive perimeter barriers to delay intruders.
This test standard rates the anti-ram barriers within three categories: K12, K8 & K4. The rating of the barrier is determined when a 15,000 lb. gross-weight vehicle impacts a barrier from a perpendicular direction. A K12 rating is achieved when a vehicle traveling at a nominal speed of 50 mph is successfully arrested by the barrier. A K8 rating is achieved for a nominal speed of 40 mph; and, a K4 rating is achieved for a nominal speed of 30 mph. In order to be DOS certified at any rating, the penetration of the cargo bed must not exceed 1 meter beyond the pre-impact inside edge of the barrier.
DOD Certified Anti-Ram Vehicle Barriers
Barrier selection must include an evaluation of site conditions to determine the acceptability and risk associated with use of barrier systems that may allow greater penetration.
Rating determined from perpendicular barrier impact of 15,000lb. vehicle.
“K” indicates the DOS certified barrier's maximum vehicle impact speed rating; and “L” indicates the test vehicle's distance of penetration upon impact with barrier.
K12 = 50 mph L3 = 3 ft. or less
K8 = 40 mph L2 = 3 ft. to 20 ft.
K4 = 30 mph L1 = 20 ft. to 50 ft.