The method specified reflects commercial practice in powder spraying. Its principle is placing, under draught-free conditions, a specified quantity of coating powder in a vessel and fluidizing it with clean dry air under standard conditions of atmospheric temperature and pressure. The height of the powder during and after fluidization is measured and the rate at which the fluidized powder flows through a specified orifice is then determined. The measurements are used to calculate the fluidization factor and the powder flow rate (flow factor) which together define the transport and spraying characteristics of the powder.