Wet film thickness, or WFT, is the measured thickness of any liquid applied coating while it is still wet. A wet film thickness gauge should be used by the applicator, as the coating is being applied, to ensure that the average applied thickness is representative of the tested wet film thickness required to meet Code. Industry best practice is to measure the WFT of freshly sprayed coating within 3 minutes of the application. Measuring the WFT of a coating enables the applicator to adjust the spray gun speed, number of spray passes and to make spray gun adjustments to ensure sufficient coating is applied to meet the fire testing without over applying which negatively affects your profits.