Common classes include: .
The design pressure and design temperature for the line are established (often based on a pump or a relief valve setting). Using the ASME B31.3 equation, the required minimum theoretical wall thickness is calculated.
: Total pressure drop must be calculated to ensure the pump or compressor can overcome system resistance. (Darcy-Weisbach). Friction factors are determined by calculating the Reynolds Number (Re)
The first half of Module 3 focuses on the behavior of fluids as they travel through a pipe. A firm grasp of hydraulic principles is non-negotiable for accurate line sizing, pump selection, and the overall operability of any process.
The code is the industry standard for process piping. It governs material selection, allowable stress, and wall thickness calculation. 4.2 Wall Thickness Calculation The minimum required wall thickness ( Common classes include:
| | Key Topics Covered | | :--- | :--- | | ASME B31.3 "Process Piping" | This is the primary code for the entire design, materials, and testing of process piping systems. | | "Piping Design for Process Plants" | A classic text on the practical design of piping systems, including sizing and pressure drop. | | "Piping Calculations Manual" | A practical reference packed with formulas and calculations for sizing and pressure integrity. | | "Line Sizing Procedure" / "Line Sizing Philosophy" | Practical, step-by-step guides that detail the specific logic and criteria a company uses for line sizing. | | "Hydraulics in Chemical Process Plants" | Focuses on practical hydraulics applications, including control valve and relief device sizing. | | API RP 14E "Design of Offshore Production Platform Piping Systems" | Industry standard for erosion velocity limitations (a critical constraint in sizing). | | "Surface Production Operations, Volume III" | An excellent hands-on manual covering fluid flow, pressure drop calculations, and pressure ratings. |
While manual calculations work well for single-line runs, complex networks require specialized hydraulic simulation software (e.g., AFT Fathom, PIPE-FLO, or Caesar II) to accurately model transient flows, parallel pumping paths, and thermal stresses. To help tailor future modules or calculations, tell me:
Resistance to flow. High-viscosity fluids (e.g., heavy oil) require more energy to move. Velocity (v): Speed of the fluid ( msm over s end-fraction ftsf t over s end-fraction 2.2 Flow Regimes (Reynolds Number)
Accurate pressure drop calculation requires understanding flow regimes (Re) and friction losses. : Total pressure drop must be calculated to
Standard thicknesses are defined by "Schedules" (SCH 10, 20, 40, 80, 160, XXS).
Recommended tools and calculation aids
Understanding how fluids behave inside a pipe is the first step in sizing and optimization. Fluid Flow Regimes
= Allowable stress value for the material at design temperature ( MPacap M cap P a A firm grasp of hydraulic principles is non-negotiable
The sizing of process piping is a balance between initial capital costs (pipe material) and long-term operating costs (energy for pumping).
Additional thickness (corrosion allowance + thread/groove depth) 4.3 Pressure-Temperature Ratings
Always cross-reference the maximum process operating temperature with the ASME B16.5 material group tables to ensure the selected flange class satisfies the design pressure. 5. Summary Engineering Checklist