Posted: 7/15/2012 2:00:15 PM EST
[Last Edit: 7/15/2012 2:25:00 PM EST by zombiegristle]
I just spent a few minutes reading the DoD Testing for SAPI and ESAPI plates, and learned a few things that I thought I'd share here.
According to the document, the specific threats tested are classified but are referred to as "A", "B", "C", and "D". SAPI plates are tested against three hits per plate from "A", "B", and "C", while ESAPI plates are tested for an additional TWO hits from "D". I'll leave speculation as to the rounds used for the reader, but I think it's reasonable to assume they used common military cartridges found on modern batlefields.
The armor is tested with a soft backing, and the results from each hit are scored according to a point system. They check for partial plate penetration, defined as a projectile embedded in the plate with no damage to the underlying soft armor (this is ideal), complete plate penetration wherein the projectile partially perforates the soft armor but does not reach the clay backer, and complete system penetration in which the projectile penetrates both hard and soft armor and continues into the clay.
I'm going to copypasta the relevant scoring text from the document below for everyone's benefit - the basic gist is, SAPI and ESAPI are both ICW plates, but ESAPI are required to met SAPI threats standalone in order to get a contract. Again however, these in no way correlate to any sort of NIJ rating so anyone claiming an ESAPI is "level III standalone" or such is either ignorant or a liar, and you should not buy armor from them.
"According to PEO Soldier officials, the ESAPI lot acceptance scoring
criteria, which were documented in solicitation W91CRB-04-R-0033, were used as a
baseline for scoring the ESAPI first article tests. The lot acceptance scoring criteria were
based on catastrophic and limited failures and a penalty point system that was applied to
the limited failures. A catastrophic failure was defined as a complete penetration of both
hard and soft armor on the first shot, or a BFD of greater than or equal to 48 millimeters
on the first shot. A limited failure could occur on either a first or second shot and was
assigned penalty points as follows:
- A complete penetration of the hard armor and a partial penetration of the soft
armor on the first shot received 1 point.
- A complete penetration of both the hard and soft armor on the second shot
received 1.5 points.
- A BFD greater than or equal to 44 millimeters but less than or equal to
47 millimeters on the first shot received 1 point.
- A BFD greater than or equal to 44 millimeters on the second shot received
The points resulting from limited failures are assigned only when testing against threat D.
For threats A, B, or C, any complete penetration on the first, second, or third shot resulted
in a failed first article test. For threat D, the accumulation of more than six penalty points
resulted in a failed first article test."
SOURCE: DoD Testing Requirements for Body Amor, Report No. D-2009-047
And on the topic of shot placement:
MORE GOOD NEWS. Apparently, the ESAPI plates were not always required to stop SAPI threats standalone, as evidenced by a footnote on page 29 of the report:
"As of June 14, 2007, PEO Soldier also assigned limited failure points to threats A, B, and C."
So, according to this, plates tested prior to that date and potentially afterward are not standalone for SQUAT. I would find it reasonable to assume that any plates from a contract granted near that date are also suspect. Note that this does not refer to the manufacture date of the plates, but rather to the date they were tested - which is certain to be PRIOR to the date the contract was granted, which is again PRIOR to the plate manufacture date.