Original Date: 03/08/1999
Revision Date: 01/18/2007
Best Practice : Paint Shelf Life Monitoring
Many materials used in government and industry contain hazardous components. Once the posted expiration dates are reached, these items are removed from inventory and disposed of as hazardous waste. In 1997, the Department of Defense (DoD) spent $230 million on handling and disposal costs for expired materials. However, studies indicate that in many cases these materials are still acceptable for their intended functions. At the request of the Navy, the Applied Research Laboratory at the Pennsylvania State University (ARL Penn State) began searching for a low cost means of monitoring the usability of these materials.
The ARL Penn State chose silicon alkyd haze gray paint as a likely candidate to monitor because of its wide use in the Navy and its similarities with other commonly used paints in the military. The laboratory determined that conductivity and polarization, as a function of frequency, reliably indicate the condition of paint.
The ARL Penn State has developed a portable interrogator for use with a smart paint stirring stick to evaluate the status of the paint. The portable measurement system connects wirelessly to other similar devices or depot-wide monitoring systems.
The micro-electro-mechanical sensor (MEMS) technology has the potential to avoid significant handling and disposal costs for hazardous waste. In addition, paint could be validated beyond the posted expiration dates to extend the shelf life of stock.
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