An environmentally-friendly fire extinguishing system developed specifically for aircraft engines and auxiliary power units could well become the new industry standard by the end of the decade.
The result of Airbus' ECOLOG (Extinguishing Concept Lowering Ozone depletion and Greenhouse effect) research project, the new system is designed to replace existing systems which use halon 1301.
Halons are excellent extinguishing agents used in numerous applications. However, due to their adverse effects on the environment, they were subject to a United Nations ban. Nevertheless, an exception has been made for certain applications such as aircraft engines, due to the lack of a viable substitute.
Airbus' new halon-free system therefore represents a major breakthrough for the environment, with its potential to replace existing halon-based extinguishers on thousands of aircraft worldwide. Designed and manufactured in conjunction with Airbus partners, a Siemens subsidiary company and SNPE, the system uses a chemical extinguishing agent invented by 3M called Novec 1230. Harmless to humans, Novec causes no damage to engine components and has little or no environmental impact on ozone depletion and global warming.
Novec's higher density meant it was not easily compatible with the existing system, so engineers from Airbus and partner companies needed to create an entirely new kind of fire extinguisher. The new extinguisher consists of a sphere partly filled with unpressurised, liquid Novec, with a gas generator containing an energetic material integrated into the upper part. Once ignited, the energetic material releases inert gases, thereby increasing pressure within the sphere and forcing the liquid Novec out through spray pipes and over the fire.
Following intensive testing by Airbus using a full-scale prototype, the new concept was presented to the Federal Aviation Administration (FAA) and the European Aviation Safety Agency (EASA) in late 2005. The concept was seen as so potentially groundbreaking that the FAA launched its own test campaign to evaluate the new agent's extinguishing efficiency. And while the FAA's findings have yet to be released, all the signs point to them being extremely positive.
In addition, team coordinator Christian Fabre, a research projects manager within propulsion engineering, is in the running for an "engineer of the year" award in the sustainable development category of French competition, "Usine Nouvelle."
Commenting on the new system, Fabre said: "Our tests show that the ECOLOG fire extinguisher design is a viable and efficient alternative to halon-based extinguisher and also fully in line with Airbus' ongoing commitment to the environment."
Airbus aims to put the new system into production by the end of the decade. As such, it could be fitted as standard on the A350 XWB and could also be retrofitted on in-service aircraft.