Perchlorate-Free Flares Undergo Qualification Testing
The U.S. Navy and Army are jointly testing two novel, perchlorate-free red flare compositions that were developed with SERDP and ESTCP support to qualify them for incorporation into service inventories. These perchlorate-free compositions have equal or superior performance compared to their in-service perchlorate-containing counterparts. When implemented by the military services, the flare compositions will eliminate the release of perchlorate from flares into the environment and, as a result, will help reduce risk to human health and the environment and prevent future groundwater contamination and costly cleanup efforts.
Perchlorates have long been used as oxidizers in military flares, rocket propellants, and other pyrotechnic materials, but studies showing that perchlorates can disrupt normal thyroid hormone production have raised concerns over their environmental impact. Most perchlorate salts are easily dissolved in water, and the potential for contamination of aquifers has prompted several states to establish stringent regulations for perchlorate in groundwater. The U.S. EPA also has initiated regulation of perchlorates under the Safe Drinking Water Act.
To address this environmental concern, the Naval Surface Warfare Center, Crane Division, with SERDP support, developed a series of perchlorate-free pyrotechnic flare compositions based on nitrates or other oxidizers. Because nitrates are less reactive, higher energy or higher specific surface area fuels were targeted for inclusion in the new pyrotechnic formulations. Using this strategy, a series of red, green, and yellow colored flare compositions were successfully developed and garnered recognition as the SERDP Weapons Systems and Platforms Project of the Year in 2006. Efforts to transition perchlorate-free red flare compositions based on this work began the following year with ESTCP support. Manufacturing of these compositions has proceeded through concept and prototype scale-ups, and production-scale batches (as large as 70 pounds) are currently being tested.
This program has evolved into a multi-service cooperative effort. The Navy is replacing a perchlorate-containing red flare composition in the Mk 124 Marine Smoke and Illumination Signal. The Army Research Development and Engineering Center (ARDEC) in Picatinny, New Jersey, is using a variant of the RSF-4 perchlorate-free red Navy composition to eliminate perchlorate in the in-service M126A1 Ground Illumination Signal – Red Parachute. As a result of extensive formulation optimization testing, both the Navy and the Army perchlorate-free red flares have been shown to give equal or superior performance in terms of candlepower intensity, dominant wavelength, color purity, and burn time when compared with their in-service perchlorate-containing counterparts. These performance tests have been conducted both at the Crane Division and most recently at the manufacturer’s test facility.
For any new pyrotechnic composition to be proven safe and accepted into the service inventories, it must successfully pass a battery of qualification tests. In the Navy, this is known as Formulation Qualification Testing and in the Army as Energetic Material Qualification (EMQ) Testing. In this cooperative endeavor, Crane and ARDEC have planned a testing program that will result in the simultaneous Navy and Army qualification of the closely related perchlorate-free red flare compositions. This approach will result in considerable time and cost savings versus that required for two separate Navy and Army formulation qualification efforts.
The perchlorate-free compositions have passed all of the required tests performed to date, and copious test results from concept- and prototype-scale batches show that the perchlorate-free compositions have comparable ignition sensitivities to in-service perchlorate-containing compositions. After these tests are completed, full-up flares based on these formulations will be manufactured and tested to demonstrate their viability and to compare their performance relative to flares currently in use.