Updated: February 19, 2003
Under sponsorship of the Combating Terrorism Technology Support Office/Technical Support Working Group (CTTSO/TSWG), an independent research study is underway to investigate the effects of naturally occurring environments on personal body armor and its component materials. The National Institute of Justice, through its Office of Law Enforcement Standards (OLES), is actively monitoring and providing technical support to this effort.
The first phase of this work is focused specifically upon the effects of temperature and moisture over time upon body armor ballistic protection materials. The study is investigating each of the three major ballistic materials used in current body armor technology for their ballistic performance response to these environmental effects. Aramid (Kevlar®), High Molecular Weight Polyethylene (Spectra®), and PBO (Zylon®) armor materials are being subjected to laboratory quality, highly controlled single and combined temperature and humidity environments. These environments are based on historically accepted military test methodologies and procedures, specified in the Department of Defense Military Environmental Standard, MIL-STD-810F, and upon climatic data gathered and assessed for regional averages and extremes within the continental United States. Both long and short-term environmental exposures are being conducted, to assess term-related effects. Ambient and extreme daily wear and storage scenarios and conditions, for example, car trunk storage temperatures, have been identified and included in the testing parameters.
Ballistic fiber material investigations in the open literature indicates susceptibility to hydrolytic and, to a lesser extent, high temperature induced degradation of fiber strength. This phenomena has been shown in research by commercial and government entities, using environmental testing methodologies and assessed using traditional strength and properties testing of individual fibers or yarns. It is important to note that little research has been found to date that directly investigates the effects of term-related environmental exposure upon ballistic impact performance of whole fabrics or armor material systems. Information from Toyobo, BSST, DSM, and the U. S. Army Natick concerning their investigations of PBO fiber strength degradation has been reviewed and considered in the design of the testing.
This study’'s test samples are being evaluated using ballistic limit (V50) testing, based on NIJ Standard-0101.04 and MIL-STD-662F methodologies and procedures, to determine if any significant reduction in ballistic penetration performance results from environmentally induced degradation to the test samples. In parallel, limited strength and properties characterizations of the materials are being conducted. The test samples consist of untreated ballistic fabrics, of both woven fiber and laminate fiber constructions, in each of the three materials. Testing is underway and is estimated for completion during the second quarter of 2003. Reporting and results are anticipated by the third quarter of 2003.
It is important to note that body armor, as a system of several material components, is generally designed to offer environmental protection to its ballistic materials; and most care and maintenance instructions, including NIJ Guide 100-01, Selection and Application Guide to Personal Body Armor, advise users about cleaning, storage, and exposure of the armor to moisture, chemicals, and direct sunlight. NIJ compliant body armor is tested while in a wet condition per the requirements of NIJ Standard-0101.04, providing a quantitative measure of the ballistic performance of the armor during a short-term extreme moisture environment. It is unclear at this time however, what effect moisture and temperature actually have upon the ballistic performance of body armor over long-term exposures. The on-going research described is expected to provide valuable insight into this question.
This page will be updated periodically, detailing the progress of this effort.
This article is courtesy of the NLECTC and OLECT.
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