This graph shows penetration energy through various numbers of layers of trigger from the EK drop tests (squares on graph) and penetration force in the FIE tests carried out by TCA and reported by Wulfe von der Russ (diamonds on graphs, normalized data). As you can see, there is a surprisingly good correlation considering the very different test methods and the different sources of trigger cloth.

The East Kingdom data is from the tests carried out by Don Thomas de Castellan and Don Dylan of the East Kingdom, posted 2/3/96 (among other dates) on various fencing lists. To summarize, it involved attaching weights to a cut off foil and dropping it a measured distance, so gives a penetration energy in joules (from the kinetic energy of the dropping weight). It gave 1 layer - 1.47 J, 2 layers - 4.12 J, 3 layers 4.7 J, and 4 layers 6.47 J.

The FIE data is reported by Wulfe von der Russ to have come from a cover letter from the FIE to TCA, dated 7/6/94, the test for 2, 3 and 4 layers of trigger had no date on it but gave 2 layers- 286 N, 3 layers- 392 N & 4

layers- 491 N. For comparison, a test done on the TCA/SCA jackets gave Dry -> 554, 583, 589, 514, 611 -> 570N and Wet -> 560, 514, 526, 537, 486 -> 525 N in a letter dated 9/93. It uses a dynamometer, according to FIE test methodology, which pushes a plunger through the fabric and measures instantaneous force required.

Note that Newtons does not directly translate to Joules physically any more than feet translates to quarts; they are different units. However, the graph shows that they correlate well; that is, you can compare them by using an empirical normalization factor. I used 76.5 to generate the graph above. In other words, divide Newtons by 76.5 to get something comparable to Joules in the EK drop test. A different type of punch test will need a different factor. The graph shows this is a fairly good match, as the curves are similar.

This means we can now use the Thomas/Dylan drop tester to do our own testing on failed jackets, and hopefully identify trouble brands and models without having to send everything to France for expensive testing. It also means we can generate some numbers to argue with, instead of just reports of failure on a subjective 4-thrust on the ground test.

For questions, contact:

Garrick Mapmaker (mka Greg Stauf) at gstauf@atmi.com