DOS standards change to reflect tighter penetration guidelines.

The U.S. Dept of State, the agency responsible for the construction and operation of embassies and their associated facilities, has changed their requirements for crash-rated anti-terrorism barriers recently. The agency is the originator of the "K" Rating which established a standard for barriers built to defeat terrorists utilizing vehicles with the intent to deliver explosives into a perimeter. This low-tech method of attack has become increasingly popular and has been used in recent assaults on oil refineries, airports, embassies, hotels, and other vulnerable facilities.  The K-rating established a standard method of testing a barrier that defined the speed and size of an attacking vehicle to be stopped within a given distance. This penetration distance allowance was called the "L" Rating.  Typically barriers were measured to stop a 15,000 lb vehicle travelling 30, 40, or 50 mph with allowed penetration distances (L-Rating) of L3 (<3 ft), L2 (3-20 ft.) and L1 (20-50ft.) This L-Rating is what has changed for DOS requirements.   

As I see it, upon further analysis of their sites, a decision was made to narrow the criteria further for acceptable penetration distance to where only those barriers that stopped attacking vehicles within 3ft. (L3-Rating) would be acceptable.  Dept. of State facilities are often located in cities with very little room for allowing penetration distances with often only a 6' wide sidewalk separating busy streets from the targeted building's walls.  The impact of this change reduces the number of barriers available that meet this requirement, particularly in a few categories. The requirement most significantly impacts the available options for perimeter fence-mounted crash barriers portable wedge-type barriers, and soft-stop or non-lethal barriers, that relied the most on stopping vehicles after penetration distances greater than the 3 feet allowed by the L3 rating.  

This change in requirements does not change the selection of products available for those that want to use the Dept. of Defense list of approved K-rated barriers.  The Dept. of Defense still allows for penetration distances of up to 50 feet past the initial perimeter as military facilities tend to have much larger footprints and larger stand-off distances.  

Bottom line: Since the barriers approved by both agencies are K-rated, make sure to clarify if you want a DOS K-12 or a DOD K-12 with a specified L rating that allows penetration greater than 3 ft.   Contact me if you have any further questions. collinsloan@sloanfencing.com