Original Date: 10/20/1997
Revision Date: 01/18/2007
Best Practice : Airflow Management
Northrop Grumman uses chromium-based primers and paint with heavy particulate content for the coatings on its F/A-18 airframes. Through Proposition 65, California law mandates that companies must notify the public via local newspaper announcements regarding all areas (hot spots) containing a chemical that is known to the State of California to cause cancer, birth defects, or other reproductive harm. This type of public announcement can be very damaging to a company’s image with the local community. In 1995, Northrop Grumman set out to eliminate the requirements for posting these public announcements by initiating an aggressive goal to reduce off-site potential health risks due to chromium VI emissions. This goal aligns with the Corporate goal (using a 1995 baseline) for a 50% reduction in toxic air emissions by the year 2001, and has eliminated the requirements for public notification of hot spots under Proposition 65.
One of Northrop Grumman’s innovative methods for reducing air emissions was its purchase of ten Portable Air Pollution Control Equipment (PAPCE) units for spray coating touch-up operations (see Figure 2-6). PAPCE, a small portable vacuum with Hepa filters, easily rolls into position to capture any overspray associated with touch-up spray coatings. Greatly valued by the employees, this compact unit operates with minimal impact on the work area and is equipped with a manometer which alerts operators to change the Hepa filters when the vacuum reaches two inches of mercury. During normal production, these filters need to be replaced every two weeks. In addition, each PAPCE displays a California air emissions permit. Northrop Grumman had to establish and obtain regulatory approval for the capture efficiency of these units. Hepa filters are designed to operate at 99.97% efficiency. PAPCE has an overall removal efficiency of 88%.
Another innovative approach undertaken by Northrop Grumman for eliminating air emissions was to outfit the roof of Building 923 with a very large Hepa filter array. This Hepa filtered exhaust system handles all of the exhaust air for the three large paint booths housed in the building. In addition, each booth is equipped with manometers which alert operators to stop spraying if two inches of mercury is exceeded.
By implementing an airflow management system for its paint and coating applications, Northrop Grumman has significantly reduced its air emissions. The company’s innovative uses for Hepa filters have decreased potential health risks due to chromium VI emissions, and reduced the hot spot areas of public notification under Proposition 65 by more than ten square miles. In addition, Northrop Grumman has had no off-site risk impact since the second quarter of 1997.
Figure 2-6. Portable Air Pollution Control Equipment
For more information see the
Point of Contact for this survey.