This article is written with young engineers entering the field of piping design in mind. In it the importance of piping materials specifications and the choice of the appropriate materials for valves in laid out for a number of industries. Similarly, attention is given to the importance in the role of datasheets and inquiry requisition. Tips for finding design information on the internet, the role of valves in piping systems, and the need to understand isometrics are also pointed out.
Piping commonly called ‘piping design’, is the detailed specification of the physical piping layout within a process plant or commercial building. In the past, this was often called drafting, technical or engineering drawing, and design. Today, it is commonly performed by designers that have learned to use automated computer-aided drawing or computer-aided design (3D CAD) software as PDS & PDMS. Piping materials is one of the specialized streams in piping design. Over the years, the role of the piping materials’ engineer has greatly evolved and expanded. Currently, the piping materials’ engineer must own the responsibility over this package from the preparation stage right through to vendor drawing approval of the package. The young generation of engineer’s (GET’s) who get into this field must learn to work with challenges like tight deadlines and the varied quality of technical documents. The topic of piping materials help them to understand the various items involved such as pipes, flanges, fittings, gasket, bolts, as well as special items like strainers, steam traps, and flame arrester, to name but a few.
Importance of Piping Material Specifications
It is important to note that all piping materials have inherent strengths and weaknesses. As such, no one material is ideal for all applications, though metals have been used longer than any other material in piping applications. It is necessary that the materials required for all piping items are properly selected, based on project specific requirements such as service, design pressure, design temperature, metallurgical requirements, and fugitive emission norms. The requirements are different for different industries/ applications, and a proper understanding of the feed documents and the basic engineering package is required. Also, a sound knowledge/understanding of process P&ID is also needed in order to capture the requirements related to special items (particularly special valves like non-slam check valves and PIV (Post Indicator Valves), etc. Correct and relevant ASME, ASTM, API, IS standards are required to be mentioned in the technical documents whilst preparing the material specifications. Piping materials offer engineers a broad spectrum of opportunities along with new challenges every day.
Role of Datasheets, Inquiry Material Requisition (MR), PMS, VMS and VDR
Piping material specifications can be considered to be one of the important pillars in finding engineering solutions and have a lot to contribute to the success of any project. For the project to be successful, care has to be taken while preparing technical documents, which include: PMS: Piping Material Specifications VMS: Valve Material Specifications MR: Inquiry & Purchase Requisitions VDR: Vendor Documents Reviews. It is imperative that correct technical details are drawn up in these documents to avoid any technical problems in later stages of the project. Before the start of any project, reference to the piping specifications is essential in order to stipulate and use the correct materials. Therefore check that you use the latest revision of the specifications. A list of applicable standards and editions is available in the basic engineering document: input from the process, metallurgy, past project experience, and it is important to realize that technical know-how needs to be developed in order to successfully prepare any technical documentation. These days a lot of online material and help topics are available on the internet. It is imperative that these are read and understood properly so that the points they raise which regards to applications are clearly reflected in the technical documentation. Also, MTO (Material Take off) is an important aspect, which is directly related to cost. In this aspect close coordination with the Piping Layout & MTO team is required.
Internet knowhow
It’s important to be abreast with latest industry trends and to have knowledge about the latest updates related to piping design. Some useful websites are mentioned below:
- www.wermac.org
- www.nace.org
- www.spiraxsarco.com
- www.pipingstudy.com
- www.asme.org
- www.processengr.com
Role of Valves
Valves are mechanical devices that control the flow and pressure within a system or process. They are essential components of a piping system that conveys liquids, gases, vapors, slurries etc. Different types of valves are available: gate, globe, plug, ball, butterfly, check, diaphragm, pinch, pressure relief, control valves etc. Each of these types has several models, each with different features and functional capabilities. Some valves are self-operated while others manually or with an actuator or pneumatic or hydraulic is operated.
Functions of valves
- Stop and start a flow.
- Reduce or increase a flow.
- Controlling the direction of flow
- Regulating a flow or process pressure.
- Relieve a pipe system of a certain pressure.
There are many valve designs, types, and models, with a wide range of industrial applications. Valves are often expensive so it is important that a correct valve is specified and that it is must constructed of the appropriate material for the relevant process.
Piping Isometrics
The piping materials engineer must also understand piping isometrics. These allow the pipe to be drawn in a manner by which the length, width, and depth are shown in a single view. Isometrics are usually drawn from information found on a plan and or elevation views. The symbols that represent fittings, valves and flanges are modified to adapt to the isometric grid. Usually, piping isometrics are drawn on preprinted paper, with lines of equilateral triangles form of 60°. Isometrics are the most important drawings for installation contractors during the field portion of the project.