Original Date: 02/23/1998
Revision Date: 01/18/2007
Best Practice : Emissions Reductions
In 1995, Northrop Grumman set out to eliminate the requirements for publishing Proposition 65 public announcements by initiating an aggressive goal to reduce off-site potential health risks due to chromium VI emissions. The company has significantly reduced its air emissions by implementing portable and stationary High Efficiency Particulate Arrester filter systems for its paint and coating applications, and eliminated the requirements for public notification of hot spots.
Northrop Grumman, Military Aircraft Systems Division (MASD) uses chromium-bearing primers and paint for the coatings on its F/A-18 airframes. Through Proposition 65 (Safe Drinking Water and Toxic Control Enforcement Act), California law mandates that companies must notify the public via local newspaper announcements regarding all areas (hot spots) containing a chemical 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. Between 1990 and 1995, toxic emissions were reduced by more than 80%.
One of Northrop Grumman’s innovative methods for reducing air emissions was its development of Portable Air Pollution Control Equipment (PAPCE), using $6,500 of commercial-off-the-shelf equipment. The company patented and built ten PAPCE units for spray coating touch-up operations (Figure 2-2). PAPCE, a small portable vacuum with High Efficiency Particulate Arrester (HEPA) filters, easily rolls into position to capture any overspray associated with touch-up spray coating operations. 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. 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%. Other potential uses for PAPCE include welding, grinding, and drilling operations. PAPCE is also effective for volatile organic compounds (VOCs). The unit has been upgraded to explosion-proof and carbon filters were installed to capture VOCs.
Another innovative approach undertaken by Northrop Grumman for eliminating air emissions was to outfit the roof of Building 923 (large-scale painting facility) 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. Benefits of the HEPA filter system include a cheaper installation cost compared to scrubbers; minimal production disruptions; simplified operational and maintenance requirements; and elimination of all groundwater and soil contamination concerns.
By implementing air emission control systems for its paint and coating applications, Northrop Grumman has significantly reduced its air emissions. The company’s innovative uses for HEPA filters 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, the Northrop Grumman, El Segundo operations had no off-site risk impact for three consecutive quarters in 1997.
Figure 2-2. Portable Air Pollution Control Equipment
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