Sloped Piping ⬇️⬇️
For all pipes which require a slope towards a definite direction, the max allowable span should be such that max deflection of pipe is less than the level difference between two adjacent support points, in order to avoid pockets.
For all pipes which require a slope towards a definite direction, the max allowable span should be such that max deflection of pipe is less than the level difference between two adjacent support points, in order to avoid pockets.
Supporting Small lines from Big Lines ⬇️⬇️⬇️
For small bore piping, intermediate supports from adjacent large bore piping may be required as an allowable span for small bore piping can be is less than the distance between two consecutive supports.
Following figure shows how larger lines in a pipe rack are used to support a group of smaller lines that may not be adequately supported because of the bent spacing.
For small bore piping, intermediate supports from adjacent large bore piping may be required as an allowable span for small bore piping can be is less than the distance between two consecutive supports.
Following figure shows how larger lines in a pipe rack are used to support a group of smaller lines that may not be adequately supported because of the bent spacing.
The un-insulated line is U-bolted to the supporting steel; the insulated line has its shoe welded to the steel.
The smaller lines then rest on the steel. When an insulated line is used for support, the growth of the line at the proposed support point must be checked. Its growth could become restricted by this type of support, and it may be better to use another line for this application.
The adjacent pipe chose as a supporting pipe must have diameter at least three sizes greater than the supported pipe, and never less than 4″.
The smaller lines then rest on the steel. When an insulated line is used for support, the growth of the line at the proposed support point must be checked. Its growth could become restricted by this type of support, and it may be better to use another line for this application.
The adjacent pipe chose as a supporting pipe must have diameter at least three sizes greater than the supported pipe, and never less than 4″.
Example : ⬇️⬇️⬇️
# Supporting Pipe : 4″ / 6″ / 8″
# Corresponding Supported Pipe : 1.5″ / 2″ / 3″
Using Dummy Support
Following figure shows the correct way to support a line that has exceeded its allowable span.
# Supporting Pipe : 4″ / 6″ / 8″
# Corresponding Supported Pipe : 1.5″ / 2″ / 3″
Using Dummy Support
Following figure shows the correct way to support a line that has exceeded its allowable span.
A common mistake is to extend the 10-in process line over the rack bent and cap it, when the line should have been run as if a support problem did not exist.
A smaller piece of pipe or dummy leg could then be welded to the elbow for support (a hole should not be cut in the process line).
A smaller piece of pipe or dummy leg could then be welded to the elbow for support (a hole should not be cut in the process line).
Supporting of Pipes of a Distillation Tower ⬇️⬇️⬇️
Supporting of pipes on a distillation tower is a critical activity involving stress analysis of almost all lines. Following points must be taken care of while supporting pipes of a distillation tower.
Piping shall be grouped as far as possible for the ease of supports. Piping shall be supported from cleats welded on the vessel as far as possible. Proper guides at recommended intervals shall be provided for long vertical lines.
Piping support cleats for safety valves shall be independent meant for safety valves only & shall be designed considering impact loading during popping off. Utility Connection nozzles shall be from side/top.
Piping support cleats for safety valves shall be independent meant for safety valves only & shall be designed considering impact loading during popping off. Utility Connection nozzles shall be from side/top.
The stress analysis requirements for supports and guides in piping connected to distillation towers and vertical vessels are as follows : ⬇️
1. The rest support must be as close as possible to nozzle. If there is a horizontal spool immediately adjacent to the nozzle, the rest support will be done shown in the sketch below.
2. The guides along the vertical run will be spaced as shown in the sketch below.
3. Ease of erection is also to be considered when positioning and spacing the guides, therefore it will be useful grouping the guides for a number of pipes at a common elevation. This criteria is valid also for columns with reinforcing rings, whereby positioning the guides on the rings, it is not necessary the welding on the shell.
4. For larger diameter piping (NPS >= 16″) standard distances between the guides are not established since support system is generally based on the stress analysis requirements.
1. The rest support must be as close as possible to nozzle. If there is a horizontal spool immediately adjacent to the nozzle, the rest support will be done shown in the sketch below.
2. The guides along the vertical run will be spaced as shown in the sketch below.
3. Ease of erection is also to be considered when positioning and spacing the guides, therefore it will be useful grouping the guides for a number of pipes at a common elevation. This criteria is valid also for columns with reinforcing rings, whereby positioning the guides on the rings, it is not necessary the welding on the shell.
4. For larger diameter piping (NPS >= 16″) standard distances between the guides are not established since support system is generally based on the stress analysis requirements.
caesar-tutorial-1.pdf
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caesar-tutorial-1.pdf
Design_and_Analysis_of_Piping_System.pdf
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Design-and-Analysis-of-Piping-System-with-Supports-Using-CAESAR-II.pdf
How to perform a pipe stress analysis ⬇️⬇️
Understanding the various types of pipe stresses, the process, and best practices are necessary to perform effective pipe stress analyses.
Understanding the various types of pipe stresses, the process, and best practices are necessary to perform effective pipe stress analyses.
Pipe stress analysis is an analytical method to determine how a piping system behaves based on its material, pressure, temperature, fluid, and support. Pipe stress analysis is not an accurate depiction of the piping behavior, but it is a good approximation.
The analytical method can be by inspection, simple to complex hand calculations, or a computer model. The computer models can vary from 1-D beam elements to complex, finite element models. For instance, if it is a water system with no outside forces applied to the piping system, inspection or hand calculations are usually sufficient. If it is a high-pressure, high-temperature, hazardous-fluids system, and/or large outside forces are applied to the piping system, a computer-aided model may be required.
Understanding pipe stress analysis software does not make for a solid foundation of pipe stress analysis. It’s important to understand the various types of pipe stresses, the process, and other items related to pipe stress analysis for best practices in performing a pipe stress analysis.
There are many piping codes and standards that could be used during a pipe stress analysis depending on the application (power, process chemical, gas distribution) and location (country or local jurisdiction). However, to keep things simple, this discussion is based on American Society of Mechanical Engineers (ASME) B31.1 Power Piping. The physics of pipe stress analysis does not change with piping code.