TABLE OF CONTENTS A piping systems forms the arteries through which a process fluid flows, and this pipe connects the various pieces of equipment that are required, within a plant, to refine the product. To facilitate changes of direction and regulate the flow, these straight lengths of pipe must be connected to piping components, valves and process equipment, to complete the system. Numerous options are available to the piping engineer responsible for specifying the correct method of jointing for a particular process piping system.
Listed here are several alternatives for joints to be used within metal piping systems:
Flanged using weld neck, socket weld, screwed, lap joint flanges.
Butt weld using a full-penetration weld.
Socket weld using a fillet weld with socket weld couplings.
Screwed using screwed couplings.
Hubbed connections using propriety hubs and collars.
Mechanical coupling victaullic-type couplings.
Soldered.
All these methods have potential leak paths, and careful consideration must be made during the material selection process and in the choice of level of inspection to minimize "in-service" fluid loss.
The joint type chosen must be leak free for the duration of the plant life. Therefore, the following factors must be taken into consideration:
Type of process fluid its toxicity and viscosity.
Design temperature range.
Design pressure.
Mechanical strength of the base material its tensile strength and ability to yield.
Size.
Weight.
Erosion and corrosion
For permanent or temporary use, need for quick release.
Quality of the labor available.
Cost.
Maintainability and reliability.
Plant life.
Need to handle vibration.
External mechanical impact from personnel, vehicles,...
