Pipe Support in Hydrocarbon Facilities: Design Considerations

The role of piping support in the correct operation of piping systems is critical as the pipe support bears the weight of the pipe and its contents. To preserve the integrity of the piping system, a pipe must be supported over an appropriate span. The overall design configuration of a pipe support assembly is influenced by the loading / operating circumstances, as well as the pipe support position. As a result, pipe support engineering and design are critical for any project’s success because it mandates the accurate and prudent selection of piping support. Conceptual planning can help with this.

During conceptual planning and the basic and detailed design engineering stages of a project, safety in design mitigates identified risks and hazards that emphasize correct material selection, manufacture, erection, and installation processes to improve process safety and efficiency over time. That is why knowledge about these is very important to piping stress analysis companies.

In this article, I will talk about the pipe support design considerations for hydrocarbon facilities and the important considerations that can be incorporated into the design.

Important Considerations in Pipe Design

Some of the important general considerations in pipe design include:

• The relative ranking of the piping and valve joints utilized in a piping system is the first step in leak prevention via design. Other piping joints, such as longitudinal seam welds and circumferential welds, can weaken the piping system.
• A stress intensification factor (SIF) should be included in stress analysis calculations to comply with ASME B31.3 or B31.1 as a measure of weakness associated with various connecting joints to fittings.
• The ASME B 31.3 fluid service classification is used to generate pipe material standards (PMS) to standardize all piping commodities for usage on a project.
• In addition to internal fluid pressure, underground plumbing must bear external loads.
• A piping engineer can ensure safety against failure due to excessive plastic deformation, gradual collapse, and low cycle fatigue.
• Design guidelines establish rules for evaluating piping loads and strains induced by internal pressure, self-weight, thermal expansion, and sporadic loads such as earthquakes, snow, and wind. To ensure compliance, these combined stresses are compared to the allowed limits.
• The piping supports in the drawing should be correctly marked for identification.
• After tagging all pipe supports, make a list in the indexed drawing of all standard, special, and temporary pipe supports.
• To prepare the piping fabrication isometrics, you must include the following information: piping material, pipe support tags, pipe size quantity, and field-fit erection materials.
• Snubbers, spring hangers, and other devices that the stress engineers of a piping stress analysis company consider vital for piping support design are used as support types. They are beneficial in extreme weather and temperature situations.
• The pipe’s loads throughout all running and standby states should be accurately assessed.
• Turbines, compressors, and pumps, for example, are particularly sensitive to piping loads, which can result in misalignment, vibration, and shortened design life. Thus, these should be maintained properly.
• The selection of a gasket material based solely on design, pressure, temperature, and material compatibility may be insufficient. Hence, all joints must survive a fire for as long as possible to provide emergency responders the most time possible.

Important Considerations in Pipe Design for Hydrocarbon Facilities

You must have gained a general idea regarding pipe support design and must be thinking about how it is different in the case of hydrocarbon facilities. Well, it is actually similar to the above with some extra other points as mentioned below.

• When planning the layout of the plant, keep hazard segregation in mind. This will help to provide built-in safety. Arranging equipment to minimize piping runs saves money, but it will also lessen the likelihood of leakage sites, especially for expensive, large-sized piping and unique material piping. Material movement is minimized by placing units closer to their raw material receiving point or final product delivery location.
• The stems of valves should be situated between the vertical and horizontal positions to be operated and maintained without hindering personnel or traffic flow.
• All components, including support standard items, will be listed on the individual-specific pipe support drawing. The piping isometric will not include any support components.
• Pipe supports are generally spaced 6m apart in process units, common pipe racks, and big facilities. For pipes with a diameter of DN 42 (NPS – 24″) or less, the distance between supports is usually chosen so that the maximum deflection does not exceed 16 mm (5/8″).
• Pipe connections to heat exchangers, compressors, pumps, and other sites where pigging and steam air decoking will be necessary should be made with removable spools, preferably with a change in direction to make extraction easier.
• Steam supply headers, drip legs, and steam traps should be 30–50 meters apart and positioned at the bottom of risers or drops. This is necessary to avoid water hammers in the system.
• Unless specified differently on the piping isometric, shoe height and length for pipes sizes DN500 and lower should be 100mm high and 300mm long, while shoe height and length for pipes sizes DN600 and above should be 150mm high and 450mm long.
• Thermo-wells and hydrostatic test vents do not require bracing. The usage of vibration is usually shown on the isometric piping.
• For ease of identification, a pipe at a plant site should be painted according to the color-coding of process fluids. The content, flow direction, design temperature, and pressure should be labeled.
• Any design problems must be addressed to the engineering team, and the engineering adjustment should only be carried out once they have given their approval. Using a 3D model during the design stage usually does not result in differences.
• Any structural steel must have a minimum thickness of 10mm for plates, bars, and rods and 6mm for rolled steel sections.

Conclusion

Building these safety features into the design and specifications of a piping system is critical for the safety of any process, and failing to do so could result in severe plant disasters. Most of these design concerns are clear to an experienced engineer, are not analytical, and maybe simply incorporated into normal design checklists to verify adherence as a quality check.