Unless otherwise specified, conduct blowing dust tests for at least 6 hours at standard ambient temperature, and an additional 6 hours at the high storage or operating temperature. If necessary, stop the test after the first 6-hour period, provided that prior to starting the second 6-hour period, the test item and chamber conditions are re- stabilized. If necessary, rotate the item to expose each vulnerable side during each of the 6-hours of exposure.
If facility limitations do not allow for the coverage of an entire face of the test item, the length of overall exposure should be extended to allow for the equivalent amount of exposure that would be performed if the facility limitation did not exist. For example, if an item with four vulnerable sides is being testing, but the facility can only cover half of each face, two exposures would be needed for each face. In this case the total time of testing would be doubled.