The development and performance characteristics of mixed flowing gas test environment

Three flowing mixed gases have been developed to achieve realistic simulation through the synergistic effects of (1) low concentrations of relevant pollutants, (2) humidity, and (3) temperature. The authors have demonstrated the importance of incorporating the sulfide-chloride synergisms into reproduced indoor field environments in order to simulate the observed corrosion response. By adjusting these variables, large differences can be found in materials reaction rates, corrosion mechanisms, and chemistries. Data were taken that demonstrate the effects of critical variables on corrosion processes. Relative humidity, reactive chloride concentration, and reactive sulfide concentration were consistently identified as the most important in all cases. Temperature, gas velocity, and NO₂ concentration were found to be far less critical. Sulfur dioxide was relatively unimportant for either indoor, field, or laboratory mixtures. It is concluded that three-component mixtures based on low levels of H₂S, NO₂, and Cl ₂ can be used to simulate all reactive environment classes