ASTM D7538-09

1.1 A newly applied traffic paint film may be exposed to rain of varying intensities shortly after application. Practice D 7377 describes a practice for evaluating the water wash-off resistance of traffic paints to a hard rain using a steady stream of water from a faucet at a rate of approximately 5.7 L per min. Practice D 7538 is a similar practice that describes the use of an adjustable nozzle atomizing spray device to deliver a spray of water that simulates rain rates from approximately 0.05 to 0.5 L per min. This test can be used to compare conventional and fast-dry traffic paints for their relative ability to withstand rain soon after application on roadway surfaces.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Significance and Use:

After waterborne traffic paints are applied to a road pavement, it is important that they be sufficiently coalesced or cured so they will not be removed by rain. This practice can be used to determine the relative water wash-off resistance of waterborne traffic paints when exposed to a water spray simulated rain.