This standard is issued under the fixed designation D ; the 1 This practice is under the jurisdiction of ASTM Committee D01 on Paint and. ASTM D Testing Water Resistance in % RH. Can be used to test the water resistance of coatings by exposing coated specimens to a high relative. ACCELERATED LIFE TESTING. Touchstone performs corrosion testing and accelerated life testing of virtually any material or device. Among the tests offered .
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If condensation is not observed on any specimen immediately after the chamber is opened, discontinue the test and determine the cause of the lack of condensation before continuing.
Rate specimens for changes in color, blistering, etc.
Other tests may also deposit water droplets on the surface but where the source is not from condensation for example, water spray. Short interruptions to inspect or remove specimens are permitted, but such interruptions should occur no more than once each day.
The level of water in the heating jacket should be approximately 30 cm 12 in. The values given in parentheses are for information only.
Report any instances of condensation non-uniformity if they occur during the exposure. Other tests are used to monitor degree of failure as a function of exposure time. This practice differs from other methods where condensation is only formed on the front coating surface, while the back surface is outside the exposure asfm. The saturated mixture of water vapor and air temperature rises and then cools below the dew point, causing condensation on the specimens.
A recovery period from 12 to 24 h is generally sufficient. Practices D cover application techniques for the production of uniform? This is a requirement in order for this procedure to work correctly.
Water permeates the coating at rates that are dependent upon the characteristics of the coating. A coating system is considered to pass if there is no evidence of water-related failure after a period of time. The use of a large heated water tank would tend to make the temperature within the chamber uniform, and thus inhibit or prevent the formation of condensate on the specimens.
Slotted nonmetallic supports are suitable for? If more than one replicate specimen is exposed, place the replicates in different locations in the exposure area. Corrosion tests can be conducted, as the condensate dripping off the test articles in not recirculated.
After the specimens ast been in an unopened chamber for at least 12 h, open the asstm and check for the presence of uniform condensation on each specimen. Three types of apparatus have been found to meet the requirements of this practice. Approved December 1, Any effects such as color change, blistering, loss of adhesion, softening, or embrittlement are observed and reported.
This saturates the air in the lower portion of the test chamber with water vapor. The values given in parentheses asym for information only. It may be necessary to avoid placing specimens in the lower portion of the chamber as the temperature differentials at the lower levels may be too small to induce condensation.
As the warmer saturated air passes the cooler specimens, water is deposited onto the specimens in the form of condensation.
Water Resistance and Humidity (ASTM D 870, ASTM D 2247)
Best practice is to use two different control specimens, one with known relatively poor performance, and one with known relatively good performance. Individual reprints single or multiple copies of this standard may be c2247 by contacting ASTM at the above address or at phonefaxor service astm.
The post-recovery rating allows evaluation of the permanent ast of the exposure as distinct from the transient effects, and is especially important for evaluation of color and gloss.
Some tests are used for a pass or fail determination at an arbitrary time. As the warmer saturated air passes the cooler specimens, water is deposited onto the specimens in the form of condensation. This practice differs from other methods where condensation is only formed on the front coating surface, while the back surface is outside the exposure area. This makes this practice suitable for flat panels as well as large or 3D objects.
The use of control specimens with known performance can also be used to determine the duration of the test that is required to produce meaningful results. Note 1—Alternative practices for testing the water resistance of coatings include Practices DD d22247, and D Material used for supports shall be of sufficient stiffness so that they do not distort or sag during prolonged use.
If any specimen does not have condensation, or the condensation is present on only part of the specimen surface, the area within mm 4 in. It is difficult to produce condensation with small chambers because the temperature differential is too slight. The substrate composition and surface preparation, specimen preparation, and the number of specimens should be agreed upon prior to testing.
Remove only as many specimens as can be rated within the speci? Users of this standard are expressly advised that d22447 of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.
The minimum distance between adjacent test specimens shall be mm. NOTE 3—Due to heat loss to the specimens and the walls of the chamber where a heated water tank is used, the temperature of the water in the tank will be above the temperature of the air and water vapor mixture.
This practice is therefore useful for evaluating coatings alone or complete coating systems. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. Such control specimens can provide warning of changes in test severity in a given apparatus, and can indicate variations in test severity between different apparatuses.
This makes this practice suitable for flat panels as well as large or 3D objects. Other tests are used to monitor degree aetm failure as a function of exposure axtm. Reverify the chamber if there are any changes to the setup of the equipment or if any 2d247 the components listed in Section 5 are repaired or replaced.
Four typical designs are shown in Fig. This makes this practice suitable for? Evaluate specimens no d2427 than 5 min and no more than 10 min after removal from test, as the effects from water exposure can change within a short time. Some tests are used for a pass or fail determination at an arbitrary time. Historical Version s – view previous versions of standard.
Before using the exposure device to this standard for the?