Efforts to find and introduce safer alternatives to hazardous materials and processes in gas turbine engine production and maintenance continue to achieve results - and Pratt & Whitney is no exception.
"Customers in our advanced engine focus groups have made it clear that they support 'green engine' efforts, and we're listening hard," says Erin Yaeger, P&W's green materials programme manager. "Based on their input, we have responded by focusing on eliminating the most commonly used hazardous materials - cadmium, hexavalent chromium, and lead."
She adds: "We've set ambitious goals for both ourselves and our suppliers to develop substitutes for these materials. We're making good progress using our rigorous 'risk management gated development' process."
The green engine initiative covers materials for new engines and the insertion of safer materials into older engines during maintenance. Processes such as stripping and coating of parts are included in the initiative. Heavy metals and chlorinated solvents are primary targets for elimination. High-risk materials are not permitted in new engine designs.
Green engines also contain materials that recycle well at the end of product life. And the greener the engine, the less it exposes workers to hazardous materials or ultimately puts them into the waste stream.
Yaeger says one of P&W's most notable achievements is the progress made in replacing cadmium-based coatings with a nickel-zinc alternative in high-pressure compressor disks, blades and spacers in legacy engines such as the JT8D and other engines of similar construction.
The alternative coating, proven in lab testing, is planned for evaluation in an industrial turbine version of the JT8D in the first half of 2005. It is targeted to be inserted in legacy engines in 2006 following FAA approval. P&W intends to use the successful development of the nickel-zinc alternative as a template to guide the elimination of other hazardous materials. Cadmium continues to be high on the elimination list. Lead, found primarily in lubricants, is also a priority.
Chrome
Perhaps the most significant target for elimination is hexavalent chrome. In anticipation of a US Occupational Safety and Health Administration (OSHA) rule that will dramatically limit the use of this carcinogenic material, P&W is evaluating substitute compounds for use in metal plating, anodizing and other applications, without sacrificing durability.
A non-carcinogenic trivalent chrome compound is showing promise as a corrosion-resistant coating for several applications, including as a seal coat for plated and anodized parts. Sulphuric acid and boric/sulphuric acid anodizing techniques are also being tested as substitutes for hexavalent chrome anodizing.
"Eliminating hexavalent chromium from our processes is absolutely necessary because both our OEM and service suppliers will see significant ramifications from the proposed OSHA requirements. The costs associated with the economics of meeting the emerging chromium requirements have the potential to dramatically affect business decisions and may well drive the replacement of those hazardous materials," Yaeger says.
To justify the introduction of new materials and processes, P&W looks at both costs and benefits. Substitutes that provide equivalent durability, while reducing waste management costs, impact on the environment and potential liability on the part of users are considered good candidates.
Source: Flight Daily News
