CREATE TABLE table_44093 ("Usage" TEXT, "Class" TEXT, "Performance" TEXT, "Performance test" TEXT, "Particulate size approaching 100% retention" TEXT, "Test Standard" TEXT)

Which Particulate size approaching 100% retention has a Usage of semi hepa and a Class of h12?
SELECT "Particulate size approaching 100% retention" FROM table_44093 WHERE "Usage" = 'semi hepa' AND "Class" = 'h12'
SELECT "Particulate size approaching 100% retention" FROM "table_44093" WHERE "Class" = 'h12' AND "Usage" = 'semi hepa'