Selection of Pipe System Materials

Q Ensure the design (including selection of materials) fabrication, assembly, test, and inspection of piping systems containing flammable liquids is suitable for the expected working pressures and structural stresses. 

Design parameters as a function of temperature and design temperature limits are set forth in the ANSI/ASME B31 Piping Codes for a very broad range of materials. These codes, and the additional information available from manufacturers, vendors, and technical societies such as the National Association of Corrosion Engineers provide ample data for the selection of materials for piping systems (1—13). 

Silicone foam thus formed has an open ceU stmcture and is a relatively poor insulating material. Cell size can be controlled by the selection of fillers, which serve as bubble nucleating sites. The addition of quartz as a filler gready improves the flame retardancy of the foam char yields of >65% can be achieved. Because of its excellent dammabiUty characteristics, siUcone foam is used in building and constmction fire-stop systems and as pipe insulation in power plants. Typical physical properties of siUcone foam are Hsted in Table 10. 

Code requirements for design and construction include service requirements, which affect selection and application of materials, components, and joints. Service requirements include prohibitions, limitations, and conditions, such as temperature or pressure limits. Code requirements for a piping system shall be the most restrictive of those which apply to any of its elements. 

Whilst carbon and stainless steels are commonly used materials of construction, increasing use is being made of non-metallic and rubber lined equipment. The selection of the material of construction should take into account the cases of the worst process conditions that may occur under foreseeable conditions and should be applied to all components including valves, pipe fittings, instruments and gauges. Both composition (e.g., chlorides, moisture) and temperature deviations can have a significant direct effect on the rate of corrosion. The operator should demonstrate that procedures are in place to ensure that potential deviations in process conditions such as fluid temperature, pressure and composition are identified and assessed in relation to the selection of materials of construction for piping systems. 

It can be concluded that selection of proper material or lining for seawater application is important and depends on the criticality of the system, availability of standby system/equipment and availability of isolation devices for maintenance. For process piping in seawater application the success of proper lining or coating material depends on the suitability for in-situ/field application and the proper corrosion monitoring plan. 

Materials-handling equipment is logically divided into continuous and batch types, and into classes for the handling of liquids, solids, and gases. Liquids and gases are handled by means of pumps and blowers in pipes, flumes, and ducts and in containers such as drums, cylinders, and tank cars. Solids may be handled by conveyors, bucket elevators, chutes, lift trucks, and pneumatic systems. The selection of materials-handling equipment depends upon the cost and the work to be done. Factors that must be considered in selecting such equipment include ... 

---