This International Standard specifies the requirements, test methods and minimum performance limits for knapsack motorized air-blast (twin-fluid) sprayers and air-assisted centrifugal sprayers as defined in ISO 5681. It is applicable to those integrally powered knapsack sprayers, equipped with an engine and carried by the operator, intended primarily for use in agriculture and horticulture (hereafter referred to as “sprayers”). It is not applicable to hydraulic pressure sprayers, thermal sprayers or cold foggers; nor is it applicable to sprayers adapted for the application of dry material. It addresses general operating parameters as well as the potential deposition of spray droplets under specified controlled conditions. It does not deal with the safety of the operator in the use of the sprayers (see ISO 28139).