ISO 22866:2005 establishes principles for the measurement of droplet drift from all types of equipment designed for applying plant protection products. Detailed specifications relate to tractor-mounted, trailed and self-propelled agricultural sprayers operating in arable field crops (boom sprayers) and in bush and tree (including vines, hops, fruit) crops (including broadcast air-assisted sprayers). The principles it defines are also applicable for any hand-held equipment or aircraft, but detailed protocols for such systems are not included in the specifications defined. It specifies the making of field measurements so as to determine the quantities of spray drift during application at defined distances from a treated area for risk assessment purposes. Standard measurement distances are defined that are used to enable the results from different experiments to be compared.