By Bob Rutherford, FSA Member [Linked article from FSA publication site]
Many associations, societies and regulatory agencies have rewritten and redeveloped emissions and leakage standards and controls year after year. The partial list of organizations—based on voluntary consensus, regulation or legislation—includes the Environmental Protection Agency (EPA), American Petroleum Institute (API), International Standards Organization (ISO), Manufacturers Standardization Society (MSS) and TA Luft. When the process rules are changed, manufacturers of seals, packing and gaskets are forced to implement changes as well. The manufacturers either produce seals that are better suited to handle the new regulations or they drop out of the market. These changes affect the way end users must look at the quality of flexible graphite and its ability to seal.
Flexible graphite is one of only a few sealing materials that increases density through compression and compaction. This significant ability is called installed density…
Several factors can cause a flexible graphite seal or gasket to lose density, including mechanical load loss or material loss. The degradation method that is seldom identified, however, is weight loss of the base material. This is why consistent quality of flexible graphite is critical. Flexible graphite is known as a high-temperature material, but high-temperature applications pose the risk of oxidation and gasket or
seal weight loss…