PIPING GUIDE: Overview of Process Plant Piping System Design by Carmagen Engineering

Introduction

This course provides an overview of process plant piping system design. It discusses requirements contained in ASME B31.3, Process Piping, plus additional requirements and guidelines based on common industry practice. The information contained in this course is readily applicable to on-the-job applications, and prepares participants to take more extensive courses if appropriate.

What is a piping system

A piping system conveys fluid from one location to another. Within a process plant, the locations are typically one or more equipment items (e.g., pumps, pressure vessels, heat exchangers, process heaters, etc.), or individual process plants that are within the boundary of a process facility.

A piping system consists of:

Pipe sections
Fittings (e.g., elbows, reducers, branch connections, etc.)
Flanges, gaskets, and bolting
Valves
Pipe supports and restraints

Each individual component plus the overall system must be designed for the specified design conditions.

Scope of ASME B31.3

ASME B31.3 specifies the design, materials, fabrication, erection, inspection, and testing requirements for process plant piping systems. Process plants include petroleum refineries; chemical, pharmaceutical, textile, paper, semiconductor, and cryogenic plants; and related process plants and terminals.

ASME B31.3 applies to piping and piping components that are used for all fluid services, not just hydrocarbon services. These include the following:

Raw, intermediate, and finished chemicals.
Petroleum products.
Gas, steam, air, and water.
Fluidized solids.
Refrigerants.
Cryogenic fluids.

The scope also includes piping that interconnects pieces or stages within a packaged-equipment assembly.

The following are excluded from the scope of ASME B31.3:

Piping systems for internal gauge pressures at or above zero but less than 15 psi, provided that the fluid is nonflammable, nontoxic, and not damaging to human tissue, and its design temperature is from -20°F through 366°F.

Power boilers that are designed in accordance with the ASME Boiler and Pressure Vessel Code Section I and external boiler piping that must conform to ASME B31.1.

Tubes, tube headers, crossovers, and manifolds that are located inside a fired heater enclosure.

Pressure vessels, heat exchangers, pumps, compressors, and other fluid-handling or processing equipment. This includes both internal piping and connections for external piping.