A standard and rapid method for determining nozzle-tip abrasion.

The wear resistance of nozzle tips used in malaria eradication programmes has, in the past, been measured with water suspensions of a variety of wettable powder insecticides. The abrasive powers of these suspensions vary greatly, and it is therefore impossible to relate the results of one test to those of another. A standard method has been devised in which a suspension of a standard synthetic powder with a high silica content is forced through nozzles, once, at 40 lbf/in(2) (2.81 kgf/cm(2)). The method is reliable, reproducible, and rapid, and it may also be used to evaluate the abrasiveness of water-wettable insecticide powders.