Regarding the connection methods for pipe branches

It depends on the diameter, material properties, and pressure. For pipelines under high pressure and subject to vibration, pipe supports must be installed; for those under low pressure, open welding is acceptable. If the branch pipe has a small diameter, a tee is not necessary. The appropriate connection for a branch pipe should be determined according to the table provided in the pipeline classification chart

Article 5.62 of the National Textbook on Pressure Pipeline Design Approval: What are the common pipeline branching structures? What are their respective characteristics? Answer: The common types of branch structures include the integral fitting type, the reinforced pipe joint type, and the welded branch type. The integral fitting type of branch structure is one in which pipes are branched using integral fittings such as tees and crosses. This type has good pressure resistance and a reliable branching structure, but it is more expensive. The reinforced pipe joint type is a method of branching pipes using special fittings such as reinforced nozzles and reinforced pipe joints. This type is commonly used in situations where branching beyond a three-way or four-way junction is required, but it is often limited by the size of the branches. Generally, reinforced nozzles (sometimes called half-fittings) are used for branches of DN40 and below, and they employ socket-threaded connections ； Strengthened pipe fittings (sometimes called branch sleeves) are commonly used for branches ranging from DN50 to DN200, and are connected by butt welding. It is also mentioned in section 5.4 of GB50316; actually, information on branch pipe connections is provided in most manuals, and detailed regulations can be found in the pipeline grade tables for each project.

Design conditions such as temperature and pressure should also be considered; calculations can be performed to determine whether reinforcement is necessary.