Currently the Department of Defense (DoD) uses potassium acetate (KAc) based runway deicing fluids (RDFs) exclusively to deice and anti-ice military runways and taxiways. Commercial airports predominantly use KAc but some also use RDFs composed of KAc plus propylene glycol (PG) or urea plus PG. These RDFs have both environmental concerns due to toxicity as well as material compatibility problems due to corrosion of carbon brake-pad components and cadmium-plated landing gear and airfield lighting fixtures.
Under the SERDP project WP-1535, Battelle developed a series of effective bio-based RDFs to address these issues. Tests showed that the Battelle-RDFs met the mandatory Aerospace Material Specification 1435A specifications. It had reduced ecotoxicity and compliant with all other environmental requirements. And, it was found to be more compatible (i.e., less corrosive) to conventional aircraft and Air-Force unique materials (such as infrared windows, LO coatings, etc.). A full-scale demonstration was conducted with two Battelle-RDF formulations: 6-12 using a partially refined bio-based material and 6-3 using a fully purified bio-based material. These fluids were evaluated under anti-icing and deicing conditions on the runway at Wright-Patterson Air Force Base (WPAFB) during January and February 2010. Runway test sections 50-ft wide by 1,000-ft long were evaluated in side-by-side tests of the Battelle-RDF and Cryotech E36® KAc RDF. Two commercial Batts deicing-fluid delivery trailers were used. The tests produced sufficient data to allow statistically valid comparisons of the two Battelle-RDFs versus commercial KAc RDF.
The objective of the demonstration was to show that an advanced RDF prepared from low-cost bio-based raw materials was less toxic, less corrosive, and as effective as commercial KAc liquid RDFs in airfield deicing and anti-icing.
The demonstration was a success. Prior to the testing, quantitative and qualitative performance objectives were established. The test results are summarized below:
- Environmental: 3 to 4 times less toxic
- Oxygen demand: Intermediate between KAc RDF and KAc+PG RDF
- Corrosion: 60 to 80% less corrosive to cadmium-plated landing gear and carbon-carbon brake pad components
- Deicing and anti-icing performance: Comparable to KAc RDF
- Ease of use: Comparable to KAc RDFs
- Maintenance requirements: Comparable to KAc RDFs.
The Battelle-RDFs were found to be suitable as a drop-in replacement for KAc RDF. A manufacturing analysis indicated that the Battelle-RDFs had lower fluid costs. A life cycle cost estimate indicated that the Battelle-RDFs had slightly higher wastewater treatment costs (due to slightly higher biochemical oxygen demand levels). But, these increased costs were insignificant compared to the savings from lower airfield and aircraft maintenance costs (due to reduced Cd and carbon-carbon brake pad corrosion).
To quantify the savings across the DoD, it was estimated that the military (primarily the Air Force) consumes approximately 1 million gallons of RDF each year. Usage is spread over 31 active USAF bases, 45 Air National Guard Bases, and 4 Air Force Reserve Command bases located in the northern half of the U.S. along with bases in Japan and North Korea. This compares to an estimated 8 million gallons of KAc RDF used at U.S. commercial airports. It was estimated that if a “typical” Air Force Base (using 31k gallons of RDF/year) switched to Battelle-RDF, the savings would be ~$92k/year. The estimated savings grew to $2.9 million if the entire DoD switched, and $28 million if all DoD and commercial airports switched to Battelle-RDF.
Users may express concern because the Battelle-RDF is new and they may have reservations because of its potential damage to aircraft or weapon system components. These reservations should be allayed once the range of tests performed and the superior corrosion properties and comparable deicing/anti-icing performance of Battelle-RDFs are disseminated.
An important implementation issue is the manufacture and delivery of the RDF. Battelle is a research and development company and not an RDF vendor. This issue was resolved when Battelle licensed the technology to Basic Solutions North America Corporation. Basic Solutions distributes the Battelle-RDF 6-4 formulation under the trade name GEN3 64™. (Formulation 6-4 is similar to 6-12 and 6-3, except it has a higher bio-based content.) During the 2009/2010 deicing season, 15 Canadian commercial airports and 4 U. S. commercial concerns used or tested GEN3. In all these commercial airport trials, GEN3 64™ was used without modification to the storage tanks, transfer pumps, deicing fluid trailers, spray nozzles, or fluid delivery pumps. This supports the conclusion that Battelle-RDFs can be readily implemented as a drop in replacement.
Prior to use in the Air Force and the DoD, the fluid was reviewed and accepted by the Air Force Civil Engineering Support Agency, the Air Force agency that provides guidance on allowable liquid and solid RDFs. Now that it has been accepted, the Aircraft Single Managers (ASMs) and Weapons System Single Managers (WSSMs) can be notified that GEN3 is approved for use. A National Stock Number (NSN) may be requested and secured to facilitate procurement. Finally, and most importantly, the ASMs and WSSMs will have to review the environmental, material compatibility, and performance data and accept GEN3 for use on their aircraft and/or weapon system. In some cases, special material-compatibility concerns may delay acceptance; or additional material-specific testing may be required by a weapon system before acceptance.