This standard practice provides format, content, and other guidelines for developing a materials selection diagram (MSD). An MSD documents the materials selection of new equipment and piping for the refinery, process chemical, power, and other industries.
This standard is intended for use by the owner/operators, licensors, and the contractor/fabricators of petroleum refineries, process chemical plants, power plants, and other industrial processing plants as a reference guide for developing an MSD to identify the materials of construction and the process conditions and other key technical issues that influence the selection of materials for use during the development and construction phases of projects.
This standard was originally prepared in 2007 and revised in 2013 by Task Group (TG) 302, “Refining and Chemicals Material Selection Diagrams: Standard.” TG 302 is administered by Specific Technology Group (STG) 34, “Petroleum Refining and Gas Processing,” is sponsored by STG 36, “Process Industry: Materials Performance in Chemicals.” This standard is issued by NACE under the auspices of STG 34.
Section 1: General
1.1 An MSD summarizes material requirements for process equipment and piping in the refining, chemical processing, power, and other industries, and provides information needed for the development of piping and instrumentation diagrams (P&IDs), piping material specifications, and equipment mechanical data sheets. In its simplest form, a typical MSD consists of a markedup or overlaid version of a simplified process flow diagram (PFD) that shows relevant operating conditions and process data, materials selection information, and application(s) of other material degradation preventive measures.
1.2 The scope of this standard is to provide format, content, and other guidelines for developing an MSD. The minimum and optional information to be included on the MSD are defined. Each user of this standard can decide whether and when the optional information shall be shown. Guidance is also provided on key issues that arise when materials are selected.
1.3 This standard does not define how to evaluate specific corrosion and materials degradation mechanisms or how to select materials for specific processes.
1.4 Sample MSDs are included in Appendix A (nonmandatory) of this standard to show format and content examples.
1.5 The intended use of MSDs is primarily associated with new capital projects, retrofit projects, and expansion projects (especially in cases in which process conditions may have changed). Because information stated on the MSD may change during project execution (because of optimizations, issues during fabrication, etc.), the MSD may become out of date. Some projects use the MSDs throughout the project, updating it as changes occur and making it “as-built,” while other projects use the MSDs only in the initial project stages. This standard covers primarily the initial MSD preparation.
1.6 The format and content of the initial MSD, its use, and its update philosophy should be agreed on by the owner/operator and the contractor/fabricator/licensor in the initial phases of the project, and meet any local regulatory requirements.
1.7 The person specifying materials of construction must be familiar with corrosion and materials degradation mechanisms particular to the type of unit being designed.
1.8 Suitable tools (e.g., NACE standards, API(1) standards including API RP 571,1 public domain isocorrosion diagrams, company proprietary corrosion data, company standards, prior operating experience, etc.) shall be used as necessary in selecting materials.