NASA's Langley Research Center has developed a new class of polyimide composite electrical insulation materials for wires, cable, and bus pipe. These new insulation materials have been shown to withstand a 12-hour gas flame test while maintaining structural and electrical circuit integrities. These extreme fire-resistant insulation systems show promise for use in high-voltage, high-power systems. They can improve survivability and continuity of the electrical power supply. Besides fire resistance, these materials also provide weight and space savings because of their lightweight nature and exceptionally high-performance capability. NASA developed the wire insulation for exploration and space operations; however, the technology also has applicability to other high-voltage, high-power systems for maritime, high-rise building construction, and other industries.
The technology combines the superb heat resistance and dielectric properties of the RP46 polyimide, reinforced with glass, quartz fibers, or fabric. RP46, developed at NASA, exhibits high mechanical strength and structural durability at elevated temperatures. It also features significantly less moisture absorption and is therefore less susceptible to moisture-induced damage. RP46 demonstrates excellent thermal oxidative stability and chemical corrosion resistance. The advantage of using glass or quartz fiber reinforcement is the ability to maintain physical integrity over a wide range of temperature, humidity, voltage, and frequency.
A copper or aluminum bus pipe insulated with the new insulation material withstood several rounds of 3-hour gas flame tests, each time being exposed to temperatures between 2100 and 2300 °F. No fire or fuse failure was observed. Results show that the insulated bus pipe can maintain both structural and electrical circuit integrity in extreme and corrosive environments.
This technology can be used in aerospace applications for space operations and exploration, marine applications for all-electric ships that require large amounts of power to be moved about the ship, and construction applications to enable the higher-voltage power lines needed for high-rise buildings.