This part specifies the technical requirements, inspection rules, marking, packaging, transportation and storage of backpack spray dusters. This section applies to backpack-type spray dusters (hereinafter referred to as backpack machines) equipped with a centrifugal fan driven by a gasoline engine and using the principle of pneumatic liquid infusion and powder transmission. Knapsack sprayers and knapsack dusters driven by gasoline engines can be used as a reference.