The use of 0.05 psi H2S partial pressure as the threshold determining when sulfide stress cracking (SSC) resistant materials are needed was codified in NACE MR 0175 (1975) nearly a half century ago and has served the industry well since implementation. The origins of this pressure are empirical and largely forgotten but there is significant history showing that it is a safe, conservative limit. As the oil and gas industry continues to innovate and mature, it is imperative to maintain knowledge of the basis of the sour limit and how it may be applied.

Subject
Hydrogen sulfide, Test methods, Tubular goods, Materials, Hydrogen concentration, Materials performance, Laboratory data, Gas pressure, Partial pressures, Ambient barometric pressure, Wellheads, Fugacity, Sulfide stress cracking
Keywords:
Corrosion science and technology, hydrogen sulfide, standardization
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2021
Association for Materials Protection and Performance (AMPP)
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