Simple Piping Design Analysis

A simple piping design analysis involves several key steps to ensure the safety and efficiency of the system . Here’s a breakdown of how to perform one:

1. Define the System :

• Gather necessary information, including piping layout drawings (P&IDs and isometrics) .
• Determine material specifications .
• Identify operating conditions (temperature, pressure) .
• Note support locations and types .
• Document equipment connections and locations .

2. Determine Pipe Size and Schedule:

• Calculate the required flow rate and velocity based on the fluid properties and system requirements .
• Select an appropriate pipe size that can handle the flow rate without excessive pressure drop or erosion .
• Determine the pipe schedule (wall thickness) based on the operating pressure and temperature, considering safety factors and code requirements .

3. Calculate Pressure Drop:

• Calculate the pressure drop through straight pipes, fittings (elbows, tees), valves, and equipment using appropriate equations and charts .
• Consider both friction losses and minor losses due to fittings and valves .
• Ensure that the total pressure drop does not exceed the available pressure head .

4. Layout and Routing :

• Route the piping in a simple, neat, and economical layout .
• Ensure adequate flexibility to accommodate thermal expansion and contraction .

5. Model the System:

• Create a 3D model of the piping system using stress analysis software such as CAESAR II, AutoPIPE, or Rohr2 .
• Include all piping, bends, elbows, tees, flanges, and supports .
• Input piping geometry, material properties, and operating conditions .

6. Support Design:

• Select appropriate supports (hangers, guides, anchors) based on pipe size, weight, and thermal movement .
• Position supports at suitable intervals to prevent excessive stress and deflection .

7. Stress Analysis :

• Input the loads the piping system will experience, including:
  * Internal pressure and temperature
  * Weight of pipe and fluid
  * External loads (wind, seismic, thermal expansion)
  * Dynamic loads (fluid flow-induced vibrations, transient events)
• The software will calculate stresses, forces, and displacements in the system based on the input conditions .
• It will compare the results against allowable stress limits set by design codes .

8. Flexibility Analysis:

• Assess the piping system’s ability to absorb thermal expansion and contraction without overstressing the components or equipment connections .
• Incorporate expansion loops, expansion joints, or flexible connectors as needed .

9. Evaluate the Results:

• After running the analysis, the results must be carefully evaluated . Key metrics to review include:
  * Stresses in each pipe segment (compared to allowable stresses)
  * Forces and moments on supports and equipment
  * Displacements at critical locations (e.g., at equipment nozzles)
  * Support loads and reactions

10. Optimize the Design:
* If the analysis reveals areas of concern, adjustments should be made to the design . Common solutions include:
* Adding or repositioning supports
* Incorporating expansion loops or joints
* Modifying the layout to reduce stresses
* Changing the material or wall thickness of the pipe

11. Verify Compliance:
* Ensure that the final design meets all relevant codes and standards .