Air Liquide’s on-board inert gas generating system (OBIGGS) can reduce the oxygen content in fuel vapors inside an aircraft fuel tank to less than 9%. OBIGGS systems prevent ignition of fuel tank vapors by providing inert gas generated onboard the aircraft. OBIGGS generated nitrogen enriched air blankets the aircraft fuel tank and displaces the flammable fuel/air mixture. The OBIGGS system consists of bleed air conditioning equipment, the air separation module, and controls to operate and distribute the nitrogen-enriched air to the fuel tanks. Air Liquide Advanced Separations' (ALaS) membranes are the heart of the OBIGGS system. Made of hollow polymer fibers, it filters an incoming air stream, removing the oxygen needed to support fires or explosions. The fibers provide a variable permeability: oxygen escapes through the membrane wall and nitrogen is fed from the membrane outlet to the fuel tank. As the fuel is used, nitrogen, which will not ignite, fills the empty space in the tank. ALaS' hollow fiber technology produces the most productive and energy efficient membranes in the industry. This translates into OBIGGS systems with lower weight and smaller space requirements.
This methodology involves ground based equipment to supply inert gas to blanket the fuel tanks. Air Liquide's extensive experience with onsite gas generation equipment has been put to use in this effort and was instrumental in the report published by the FAA - DOT/FAA/AR-00/19.
Air Liquide has been involved in selectively permeable membrane based OBIGGS for military aircraft for over a decade and is the leading supplier of permeable membrane-based OBIGGS to the industry. Air Liquide's early participation in the industry's A12 and F117 programs provided valuable experience in which Air Liquide continue to innovate on.