ASTM G85:A4 Salt/SO2 Fog (Spray) Testing

Salt/Sulfur Dioxide Spray (Fog) Testing

ASTM G85 Annex 4 (A4) is a corrosion test which introduces SO2 gas directly into the salt spray chamber or cabinet according to specified cycles. The SO2 gas is introduced into the chamber in a manner that will insure uniform dispersion within the chamber.

Salt Solution: The salt solution is defined within the ASTM method but can be altered where mutually agreed upon by the lab and customer. The salt solution is typically made up of synthetic sea salt or sodium chloride.

pH Range: 2.5 – 3.2

Test Temperatures: The temperature in the exposure zone of the salt spray chamber or cabinet is to be kept constant at 35°C +/- 2°C or (95°F +/- 3°F). The temperature of the saturator tower (bubble tower) is to be kept at 47 +/- 1°C (117+/- 2°F)

Test Cycle: There are two test cycles specified by ASTM G85 Annex 4 (A4).

Constant spray with introduction of SO2 gas for 1 hour 4 times a day (every 6 hours)

1/2- hour salt spray followed by ½ hour SO2 injection and then a 2 hour soak.