How are manual shut-off valves typically connected to piping?

Manual shut-off valves are typically connected to piping using flanged connections due to the need for a secure and easily dismountable assembly. Flanged joints consist of two flanges with gaskets in between, which are bolted together. This method allows for a tight seal that can handle the pressures involved in gas piping systems while enabling easy maintenance or replacement of the valve without cutting or damaging the pipe.

Flanged connections are particularly advantageous in larger diameter piping or when working with high-pressure systems because they can better accommodate the stresses that arise during operation. Additionally, they allow for accurate alignment of the piping and the valve without introducing mechanical stress to the system.

Other connection methods, such as threading or welding, may not provide the same level of versatility or ease of access, especially in scenarios where frequent service is required. While soldered connections may be common in some plumbing applications, they are not typically used for manual shut-off valves in gas piping due to concerns over joint integrity under varying temperature conditions.