When to use a union in piping system?

A union in a piping system is used when a connection needs to be easily disassembled for maintenance or repairs without cutting the pipe. It allows for quick separation of two pipe sections while maintaining a secure and leak-free joint during operation. Unions are typically employed in applications where frequent disconnection is anticipated, such as in service lines or where equipment may need to be replaced. Additionally, they can be beneficial in tight spaces where there isn’t enough room for a traditional flange connection.