Moist air containing sulfur dioxide quickly produces easily visible corrosion on many metals in a form resembling that occurring in industrial environments. It is therefore a test medium well suited to detect pores or other sources of weakness in protective coatings and deficiencies in corrosion resistance associated with unsuitable alloy composition or treatments.

The results obtained in the test should not be regarded as a general guide to the corrosion resistance of the tested materials in all environments where these materials may be used. Performance of different materials in the test should only be taken as a general guide to the relative corrosion resistance of these materials in moist SO₂ service.

1.1 This practice covers the apparatus and procedure to be used in conducting qualitative assessment tests in accordance with the requirements of material or product specifications by means of specimen exposure to condensed moisture containing sulfur dioxide.

1.2 The exposure conditions may be varied to suit particular requirements and this practice includes provisions for use of different concentrations of sulfur dioxide and for tests either running continuously or in cycles of alternate exposure to the sulfur dioxide containing atmosphere and to the ambient atmosphere.

1.3 The variant of the test to be used, the exposure period required, the type of test specimen, and the criteria of failure are not prescribed by this practice. Such details are provided in appropriate material and product purchase specifications.

1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.5 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. For a specific warning statement, see 4.3.