This document specifies the requirements and test methods for inspection of the use of knapsack sprayers carried on the back or shoulder of the operator for use with plant protection products (PPPs). The requirements relate mainly to the condition of the sprayer with respect to its potential risk to the operator and the environment and its performance to achieve good application. It is applicable to lever-operated knapsack sprayers, knapsack compression sprayers and knapsack sprayers driven by an engine or electric motor using hydraulic pressure atomisation of the spray liquid, intended for use primarily in agriculture, forestry and horticulture, with a nominal volume of more than 6,0 l. This document does not apply to knapsack combustion engine-driven air-blast sprayers, which are covered in ISO 28139:2019/Amd 1:20XX. controlled droplet application equipment utilizing rotary atomisers, or portable application equipment for spatial application (such as foggers).