Engineering Materials – What Is Piping

Piping Materials Engineers work quietly to ensure the reliability, safety, and integrity of critical piping systems in the oil and gas, petrochemical, power generation, and other industrial sectors. They play a crucial part in the selection, specification, and management of piping materials, ensuring that every pipe, fitting, flange, valve, and gasket stands up to the operational demands and environmental challenges it faces. A piping materials engineer is a mechanical, metallurgical, or chemical engineer specialized in selecting and specifying materials for piping systems used in industrial facilities such as refineries, offshore platforms, chemical plants, and power plants. Their decisions directly affect the safety, cost-efficiency, and longevity of piping networks, making their expertise essential during the engineering design phase of a project. Good piping material engineers are always in demand, and frequently they face interviews for various engineering positions. In this article, I will list some of the most frequently asked questions to help them prepare for any upcoming interview. Piping Material Engineer Interview Questions Here is a list of some of the most common interview questions for a piping material engineer. If you know some more questions that need to be added to this list, please specify those in the comments section, and I will add them to the main list from time to time. As a piping materials engineer, what roles have you performed in your previous company? Have you performed pipe thickness calculation? Can you specify the pipe thickness calculation formula as per the ASME B31.3 code? What is the significance of the E factor and W factor in the pipe thickness calculation formula? What are the parameters on which the E factor and W factor depend? What is the meaning of mill tolerance? What do you understand when it is said that mill tolerance is 12.5%? Does mill tolerance always remain at 12.5% or does it vary? From where to get the values of mill tolerance for pipe thickness calculation? Do E, W, and Y factors change or remain constant? If changes, can you specify how? What is corrosion allowance, and from where to get the value of corrosion allowance? Who will decide the corrosion allowance value? What do you consider when there is a vacuum condition in a piping system? What is the branch thickness calculation philosophy? When and why do we perform branch thickness calculation? What is Piping Material Specification and Piping Class? Have you ever generated any PMS or Piping class? What are the considerations? What are the differences between a PMS and a piping class? What information is typically included in a piping material specification? What are the input documents to a PMS? What information does a PMS give? What do branch tables specify? What is the difference between a stub-in and stub-on connection? Which one is stronger? ASME B31.3 specifies two pipe thickness calculation formulas. How do you decide which one to follow? What are the assumptions for pipe thickness calculation based on ASME B31.3? Have you worked in power piping (B31.1)? For the same piping with the same temperature and pressure conditions, which code will provide thicker material, and why? What are the common pipe fittings, and what are their governing design codes/standards? What are the differences between a code, a standard, and a specification? Valves are designed based on which standard? What are the different types of valves, and how do you decide the materials forthe valve body? What is the meaning of valve trims? In general, valve trim is of which materials? What is the meaning of VMS? Explain the terms: MTO, BOQ, BOM What are the stages of MTO? For a design temperature of -46° C, which piping material is generally used? For a piping material of A-106 Gr B, what is the common fitting material? What is the impact of temperature on material selection? What are the major differences between A106 Gr B and Gr C? What is TBE, and what is the role of a piping material engineer in TBE? Have you heard the term, Piping Specialty Item? Can you please provide 5 examples of piping specialty items? What is the equation for Line Blank Thickness Calculation? Have you prepared any datasheets for piping specialty items? If yes, what are the contents of a datasheet? As a piping materials engineer, do you use any software? Are you aware of the term "SMAT" or "SPM", AVEVA ERM, and PUMA? What are the different types of ferrous materials you know? What are the differences between low alloy steel, high alloy steel, and LTCS? How do you decide when to use seamless vs welded pipe? What is CE value? Have you heard the term PREN? What are the differences between SS and DSS, and when are they chosen? What is the meaning of dual-certified material? What are the piping flange standards for a 16-inch and 32-inch pipe? Can you specify some differences between ASME B16.47 series A and series B flanges? What is the meaning of galvanized steel? When do you choose galvanized steel? What is the major difference between ASTM A312 TP 304, TP 304L, and TP304H? What is the difference between different stainless steel grades? How do you select materials for sour service (H₂S environments)? What is the importance of NACE MR0175? What are the typical materials used for cryogenic services? What factors influence your selection of piping material for a high-temperature, high-pressure service? What is PWHT, and when is it required? Describe how you handle corrosion allowance in piping design. What is galvanic corrosion and how do you prevent it in piping systems? Can you describe the difference between duplex and super duplex stainless steels? What are typical issues encountered with DSS and SDSS in fabrication? Have you heard the term, MTC? What do you check in a Material Test Certificate (MTC)? Describe how you develop a piping material class from scratch. How do you link a piping material specification to 3D modeling software? How do you assign valve materials in piping classes? What is the meaning of LLI? How do you handle long lead items or material shortages? How do you track and control revisions in piping material specs? What is the importance of PMI (Positive Material Identification)? How do you ensure material traceability throughout a project? How do you manage piping material delivery for a brownfield revamp? What is the difference between CS and LTCS piping materials? Explain the difference between ASTM and ASME material specifications. What are your responsibilities during FAT (Factory Acceptance Testing)? What is the difference between DSS and CRA piping materials? Describe the selection criteria for cladding vs. solid alloy piping. How does hardness testing relate to material selection for sour service? What’s the significance of impact testing in low-temperature services? How do you manage material compatibility in dissimilar joints? How do you select gasket materials for high-pressure and high-temperature service? What’s the difference between NACE MR0175 and MR0103? What is HIC and how do you mitigate it? How do you deal with ambiguous specifications or missing information? How do you evaluate suppliers for piping materials? Describe your experience with VDRL (Vendor Document Requirement List). What are the metallurgical differences between forged and cast components? How do you coordinate with process and mechanical teams on material selection? What lessons have you learned from site execution involving piping materials? How do you handle conflict with vendors or procurement over specs? Have you ever challenged a design or spec due to material concerns? How do you ensure integration of MTO data across disciplines? How to decide the Hydrotest Pressure for oil and gas piping? What are the criteria for Hydrostatic testing and pneumatic testing? Have you used A106-Gr B material for (-)45 Deg C temperature? Can it be used? Under What condition? What is the type of corrosion allowance selected for a pipe subjected to internal pressure? Explain in detail the procedure to check whether the pipe is suitable when subjected to external pressure. What is the basic concept behind the Rpad calculation? How is the impact test considered for the ASTM 516 plates? What are the design requirements of a valve subjected to cryogenic service? Why is a spectacle blind generally not preferred or used in cryogenic service? What are the important points/clauses to be considered while preparing the Technical or Purchase or Supply specification? What is the procedure from MTO preparation to the issuance of Inquiry MR to TBE to Issuance of Purchase order? What are the documents required to be attached while issuing MR? What are the generally used design standards for gate, globe, check, ball valve, and plug valves? What is the standard to specify a valve as fire-safe? What is the fire-safe requirement in a valve? What are the general temperature limits for BUNA-lined, EPDM, PTFE, and metal seats used in valves? What is the difference between API 600 and ASME B16.34? What are the requirements to select a suitable trap size? What are the different types of strainers? For a 16” Tee type strainer, end connection with Flanges or Buttwelded which is more beneficial and why? What is the total amount of man-hours you worked on a single project, and the number of MR/POs handled? What were the earlier and present exemption thicknesses for carbon steel material subjected to PWHT as per ASME B31.3? What do you include in a component datasheet? If you are aware of any additional questions that you have faced in any interview, kindly mention those in the comments section.