All piping over 2 inches must be what type of welded?

In the context of high-pressure boiler systems, the requirement for all piping over 2 inches to be butt welded is based on the need for strong, leak-proof joints that can withstand high temperature and pressure conditions. Butt welding involves joining two pieces of pipe end-to-end, creating a continuous and uniform joint that is ideally suited for handling the stresses experienced in such applications.

This method provides superior strength and structural integrity compared to other welding techniques, making it essential for ensuring the safety and reliability of high-pressure boiler systems. The design of butt welds allows for a smoother internal flow within the piping, minimizing turbulence and potential pressure drops.

Other welding methods, such as spot welding, fillet welding, or screw welding, may be suitable in less demanding contexts but do not provide the same level of performance and safety required for high-pressure applications. Spot welding typically joins thin sheets of metal rather than thick piping, fillet welding is often used in situations where a corner joint is necessary rather than on the ends of pipes, and screw welding is not a standard term used in the context of piping systems. Hence, only butt welding meets the stringent criteria necessary for high-pressure systems.