Non-Hazardous Solvent to Clean Composite Aircraft Components
Ongoing ESTCP project WP-201414 is working to qualify and transition an environmentally compliant cleaning solvent for the efficient removal of hydraulic fluid and other contaminants from DoD aircraft composite structures. Current petroleum-based solvents are widely used in the U.S. military but contain hazardous air pollutants ( HAPs) and volatile organic compounds ( VOCs), which cause health and environmental problems. Typical petroleum-based solvents such as mineral spirits, Stoddard Solvent, PD-680, and MIL-PRF-680 contain significant quantities of these compounds that release into the air during cleaning processes and contribute to the level of ground-level ozone (photochemical smog), which can damage lung tissue, cause respiratory illness and damage vegetation.
To address this problem, NAVAIR developed NAVSOLVE™, a non-petroleum-based solvent cleaner which meets stringent low-VOC and HAP-free specifications such as those of California’s South Coast Air Quality Management District, as well as the DoD’s own MIL-PRF-32295A “Cleaner, Non-Aqueous, Low-VOC, HAP-Free.” NAVSOLVE™ is currently the only composition that meets MIL-PRF-32295A for Type II cleaners, which involve immersion cleaning for aircraft parts and ground support equipment.
Earlier validation field tests for NAVSOLVE™ were conducted at seven DoD testing sites (Navy, Air Force, Army, and Marine Corps) to clean aircraft and ground support equipment metallic parts. The current ESTCP program extends the validation to the typical polymer based composites, adhesives, and cores used in aircraft components. First, coupon level mechanical tests are being conducted to ensure NAVSOLVE™ compatibility with several composite materials and structures used on a range of DoD aircraft. Next, several field tests will be executed to validate successful NAVSOLVE™ substitution for current hazardous solvents in DoD cleaning and repair procedures for composite aircraft parts and cores. The three demonstrations sites are the Navy Fleet Readiness Center-East (Cherry Point, NC), Fleet Readiness Center-Southeast (Jacksonville, FL), and Hill AFB (Ogden, UT). The demonstration test articles include components from the F-35, V-22, and MC-4Q Triton UAV/Globalhawk aircraft.
NAVSOLVE™ is a low-VOC, HAP-free, non-ozone depleting substance which is recyclable, high flash point, fast drying, and compatible with metal and non-metal materials. This makes it an overall safer and more environmentally friendly alternative for DoD cleaning applications. Successful demonstration of NAVSOLVE™ will lead to the replacement of the more hazardous solvents that are currently used.