High performance gas turbine inlet filter (HEPA) using membrane media

A gas turbine air inlet filter element including:

• a first end cap;
• a second end cap;
• and
• a filter media, said filter media including:
• a nonwoven synthetic fabric formed from a plurality of bicomponent synthetic fibers with a spunbond process;
• a surface layer deposited on one side of the base substrate wherein the surface layer is formed from a microporous expanded polytetrafluoroethylene membrane;
• wherein the base substrate and the surface layer are configured to provide greater than 95% and equal to or less than 99.5% filtration efficiency measured in accordance with an EN 1822 test method;
• wherein said filter media further including an embossing pattern or a plurality of corrugations, said embossing pattern or said corrugations formed using opposing rollers at a temperature of about 90° C. to about 140° C.;
• and
• the composite filter media structure provides the greater than 95% and equal to or less than 99.5% fractional efficiency at pressure drops between approximately 0.60 inches of water and 3.05 inches of water.