KS B ISO 13347-4:2020 Industrial fans — Determination of fan sound power levels under standardized laboratory conditions —Part 4: Sound intensity method
2020KS B ISO 13347-4:2020 Industrial fans — Determination of fan sound power levels under standardized laboratory conditions —Part 4: Sound intensity method
2005KS B ISO 13347-4:2005 Industrial fans-Determination of fan sound power levels under standardized laboratory conditions-Part 4:Sound intensity method