Pipe material specifications

Figure 1-26. Partial presentation of piping materials specifications for a specific process service. By permission, Borden Chemicals and Plastics, Operating Limited Partnership. (Figure continued on next page)...

PIPING MATERIAL SPECIFICATIONS (continued) Alternate Process Service... 

An excellent summary of codes and pipe material specifications is given in Piping... 

C. Instrumentation. In-line instruments are exposed to the same conditions as process equipment and piping. Materials specifications are at least as rigorous as they are for these other systems. Instruments contain more small parts, are built to more rigorous tolerances, and often depend on their accuracy for precise and intricate movement of parts. The corrosion allowances associated with equipment and piping cannot be tolerated. 

The principal plastic piping material specifications are issued by the American Society for Testing and Materials (ASTM). Earlier ASTM standards classified plastic materials by type, grade, and class in accordance with three important properties. ASTM used a code that consisted of four digits and a product letter prefix indicating the resin. The four digits stood for ... 

The specific electrical resistances usually depend on the material and the temperature [31]. For the most important pipe materials these are (in 10 Q cm) ... 

Common items such as valves, piping and welding electrodes which may be supplied for a large plant in half a dozen material specifications can become mixed up due to poor identification marking. 

Boiler and Pressure Vessel Code, Section II, Materials (Part A, Ferrous Material Specifications, and Part D, Properties ), Section ID, Rules for Construction of Nuclear Power Plant Components, and Section VIII, Pressure Vessels, Divisions 1 and 2. Code for Pressure Piping, ASME/ANSI B31.3, Chemical Plant and Petroleum Refinery Piping ... 

Material Specification Index for Piping and Pipe Components. 

Table GR-2.1.1(a) Material Specification Index for Piping and Pipe...

Metallic piping materials and components shall be prepared for fabrication and erection by the requirements included in this Chapter and the additional chapters of Part IP, along with the general requirements of Part GR, and mandatory appendices. When required by the engineering design specifications, the nonmandatory appendices shall become mandatory. 

Cold Bent and Formed Piping. The hardness testing method, area of survey, and acceptance limits shall be specified by the material specification and/or the engineering design. 

When required by design, material specifications, and qualifications for welding and brazing, one or more of the tests maybe required, in addition to the test required for the construction of the piping system. 

For use in Code piping at the stated stress values, the required minimum tensile and yield properties must be verified by tensile test. If such tests are not required by the material specification, they shall be specified in the purchase order. 

Environmental stress cracking (ESC), usually associated with SCG accelerated by surfactants or other aggressive media, is also of considerable interest in its own right, since pipe materials are often intended for service in contact with water or other industrial fluids. Oxidative degradation is another important concern, particularly at high temperatures, and stabilisers are often added specifically to retard SCG and catastrophic failure [65, 66, 67, 68], the stabiliser type and concentration being critical at very low SCG rates, even where they have little effect on rapid fracture [69]. 

---