ASTM D7539-10 (R2020) PDF Download

ASTM D7539-10 (R2020) provides guidelines for using a test chamber to control relative humidity above ambient humidity and minimize air flow during the conditioning of test panels at elevated relative humidity and room temperatures.

The practice is specifically useful for testing the drying rate of waterborne pavement marking paints, where fast dry at elevated ambient humidity is an important feature. It allows for the evaluation of dry to no-pick-up and water wash-off resistance at elevated ambient humidity.

The standard practice is necessary because the drying rate of organic coatings, especially waterborne paints, can vary with changes in temperature, air flow, and relative humidity. Standard ambient conditions in laboratories cannot adequately replicate the drying conditions of waterborne paints without some control. Therefore, the test chamber described in this practice provides a means to control relative humidity and minimize the effects of air flow variability during the conditioning of test panels.

In addition to controlling relative humidity, the test chamber can also be used in a temperature and humidity controlled room to test dry speed at various temperatures while using the chamber to minimize the effect of air flow.