API TR 939-D is a technical report for professionals evaluating stress corrosion cracking of carbon steel in fuel grade ethanol. The document, titled Stress Corrosion Cracking of Carbon Steel in Fuel Grade Ethanol— Review, Experience Survey, Field Monitoring, and Laboratory Testing, brings together technical background and interpretive insight for buyers who need a deeper understanding of this material-environment issue. API TR 939-D can help teams assess risk, compare experience, and support informed decisions in ethanol handling and related carbon steel service where cracking concerns may affect reliability and safety.

Purpose of API TR 939-D

The purpose of API TR 939-D is to provide a technical reference on the behavior of carbon steel in fuel grade ethanol, with emphasis on stress corrosion cracking and the evidence gathered through review, field monitoring, and laboratory testing. As an API technical report, it is best understood as background and evaluation material rather than a prescriptive requirements document. It is useful for specialists who need context when reviewing material suitability, comparing operating experience, or supporting internal engineering studies related to ethanol service.

How API TR 939-D may be used

API TR 939-D is commonly consulted by engineering, integrity, reliability, and inspection personnel involved in fuel ethanol or adjacent hydrocarbon handling systems where carbon steel performance needs review. It may support technical assessments, project studies, maintenance planning, and operational reviews for tanks, piping, terminals, or other equipment exposed to fuel grade ethanol. Procurement and project teams may also use it as a reference when evaluating materials-related risk and aligning specifications with internal reliability expectations.

Why API TR 939-D matters

This technical report matters because stress corrosion cracking concerns can influence material selection, inspection priorities, and long-term asset reliability. API TR 939-D gives decision-makers and subject-matter experts a documented basis for comparing experience and evaluating whether carbon steel is appropriate in a given ethanol service context. For day-to-day professional use, it can improve technical consistency across engineering review, inspection planning, and maintenance decision-making, while helping reduce uncertainty in procurement and project support work.

• Carbon steel performance in fuel grade ethanol
• Stress corrosion cracking evaluation
• Review of field experience and monitoring
• Laboratory testing and technical comparison
• Engineering, integrity, and inspection reference use
• Support for reliability and material-risk review