ASTM G91-97(2004)

Atmospheric corrosion of metallic materials is a function of many weather and atmospheric variables. The effect of specific corrodants, such as sulfur dioxide, can accelerate the atmospheric corrosion of metals significantly. The sulfation plate method provides a simple technique to independently monitor the level of SO₂ in the atmosphere to yield a weighted average result.

Sulfation plate results may be used to characterize atmospheric corrosion test sites regarding the effective average level of SO₂ in the atmosphere at these locations.

Sulfation plate testing is useful in determining microclimate, seasonal, and long term variations in the effective average level of SO₂.

The results of sulfation plate tests may be used in correlations of atmospheric corrosion rates with atmospheric data to determine the sensitivity of the corrosion rate to SO₂ level.

The sulfation plate method may also be used with other methods to characterize the atmosphere at sites where buildings or other construction is planned in order to determine the extent of protective measures required for metallic materials.

1.1 This practice covers a weighted average effective SO2 level for a 30-day interval through the use of the sulfation plate method, a technique for estimating the effective SO2 content of the atmosphere, and especially with regard to the atmospheric corrosion of stationary structures or panels. This practice is aimed at determining SO2 levels rather than sulfuric acid aerosol or acid precipitation.

1.2 The results of this practice correlate approximately with volumetric SO2 concentrations, although the presence of dew or condensed moisture tends to enhance the capture of SO2 into the plate.

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.