Two years have passed since our review of the 2023 Personal Armor Systems Symposium, and another one has come and gone. PASS 2025 – which took place in Bruges, Belgium, under the auspices of the Belgian Royal Military Academy – brought together the leading experts in the field for several days of talks and meetings. A few of its presentations may be of interest to a wider audience; I will summarize select highlights below and return with more in a follow-up article.
Testing flexible “hard” plates that bend to fit (Canada)
This presentation was led by researchers working out of the Canadian Defense Department’s R&D labs in Valcartier. They opened by noting that there’s “a growing requirement for body armour that can accommodate a more diverse population and a larger range of body morphologies,” and that flexible rifle armor might be an elegant way to meet this requirement. Yet while flexible rifle armor claims to meet military performance requirements, the authors note that there is “limited test data” available on such systems.
So, to shed more light on their performance characteristics, six different types of flexible rifle plate were procured for testing. All of these plates claimed to be compliant with NIJ .06 Level III(+). Most utilized hexagonal ceramic elements that were 30mm in diameter from flat to flat, though a couple made use of slightly larger hexagonal tiles. Only one plate was appreciably different; this one utilized metallic titanium tiles that were 60mm in diameter. The paper did not disclose who manufactured any of these plates, nor did they examine the ceramics or alloy utilized, except in the vaguest of terms.
The plates were tested in two wear configurations — in a SAPI-style curvature, and in a more heavily flexed “female armor plate” type of curvature (NIJ C-5 female curvature) – against three threats – 5.56mm M855 [C77], 7.62mm M80 [C21], and a Canadian 7.62mm API-BZ surrogate. The authors set up the test so that every plate is shot at tile centers, and over gaps between tiles.
Over 116 shots, complete penetrations were very rare, and mostly (though not entirely) limited to the metal-faced design. (And, in fairness, it’s not entirely clear what threats this plate was rated for.) How the plates were curved, and where they were impacted, made no apparent difference in performance. It was found, however, that backface deformation values typically exceeded the NIJ’s 44mm limit. Average BFD against the M80 Ball was never lower than 43.5mm, and some plate designs were at over 60mm on average.
Though the authors expressed surprise and concern at this finding, I’d note that although the NIJ retains a 44mm limit, some Army plate programs have accepted up to 58mm BFD; by that yardstick, only one model in this study averaged >58 mm. Thus the presentation suggests that modern flexible rifle armor can be designed and utilized by military forces, which is a noteworthy finding: A near-term path to better-fitting rifle protection for diverse body types.
Full text: “Ballistic evaluation of flexible hard armour plates in bent and flat configurations” — J. Bélanger, S. Ouellet, G. Pageau.
Optimizing Plate Size and Coverage (Canada)
Another Canadian DRDC paper out of Valcartier, this presentation examined how SAPI-type plate sizing – width and length – affect survivability in an anatomical torso model representative of the average soldier.
With 10,800 simulated shot lines over multiple azimuths, the paper maps survivability vs. plate length/width with injury metrics (AP/ISS/NISS).
Another Canadian DRDC paper out of Valcartier, this presentation examined how SAPI-type plate sizing – width and length – affect survivability in an anatomical torso model. Using CORE V/L with a 50th‑percentile male avatar, they swept 49 geometries and ran 10,800 simulated shot lines at −45°, 0°, and +45°. Plates were idealized as perfectly blocking on intersection; injuries were mapped to AP/ISS/NISS anatomical models.
The signal is clean: Relative coverage area dominates. Survivability climbs monotonically with area, and oblique shots expose upper/lateral thorax that looks covered head‑on. At fixed area, length vs. width matters only at the margins—larger plates benefit most from max width with modest extra length; smaller plates do best with a balanced split. Curvature/aspect help mainly once coverage is already high. Within the model’s bounds, the practical guidance is to set total area first, then bias added millimeters toward width before chasing exotic outlines, with population variance and multi‑objective (fit/thermal/weight) optimization as the next step.
Overall, the findings are consistent with historical edge-adjacent wound patterns, noted as early as 2005 in “Marine Lethal Torso Injuries: Preliminary Findings – 8/29/2005”:
“The areas around the plate (generally above and to the side) accounted for nearly 42% of the lethal wounds we examined. Thirty-one of these were in close proximity to the plate edges. Either a larger plate or superior protection around the plate would have had the potential to alter the fatal outcome.”
Though the paper doesn’t state this outright, it seems to imply that larger plates with more significant lower-edge curvature – like the old UK Army Osprey plates – would be superior in survivability to the SAPI. It’s well-known that the Osprey was generally not properly human factors engineered, but if the lessons of this presentation are taken to heart, we may see future experimentation in extended-coverage torso plates.
“Relative effect of ballistic plate coverage on the protection system performance” — G. St-Onge, A. Bouamoul, S. Ouellet.
Cooling the Armor-Wearer (Netherlands)
A TNO-Inuteq team presentation reported a ventilated armor carrier. The integration work appears highly practical and soldier-centric: The controller is embedded in the cable, the cables themselves are tidy, it uses fans customized for ~30-40% lower power draw and ~10 dB less high‑frequency noise, and it runs off the standard Bren-Tronics battery. The cooling comes without sacrificing protection, as tests show that there’s no negative impact on armor V50 performance.
In a 5‑day field study in ~45 °C heat, the active carrier outperformed a commercial uncooled carrier on operational usability, comfort, perceived temperature (lower), and cooling; soldiers chose to run the carrier in full‑speed continuous cooling mode ~80% of the time, which, more than anything else, indicates strong user acceptance. The net result: An (almost-)ready-to-field, low-risk upgrade that slots into existing PPE and power ecosystems while extending endurance, cognitive performance, and comfort in hot environments.
If there’s a caveat, it’s that wars have moved beyond the sandbox. The hottest conflicts on the globe are now being fought under temperate northern skies. In Ukraine, specifically, heat is almost a non-factor; cold weather causes many times more casualties. It is therefore unclear whether contemporary European/American military forces will see much benefit from cooled vests. Surely a must-have for cops in Florida, though!
“Recent developments of an active ventilated vest for military use” — S.B. Ballak, B. Vos, E. Bakkers, E. Hesen, F. Vuijk, L.L. Ahsmann, S. Golembiewski, M. Catoire, L. Klous.
That is a sample from Bruges. In the next piece in this series, I will cover several additional talks. Stay tuned for more from PASS.
