What linkage is required for gas piping to prevent leaks and maintain safety?

The requirement for gas piping to use specific linkages is essential in preventing leaks and ensuring safety in installations. Among the provided options, the use of bell reducers plays a significant role in gas piping systems because they allow for the connection of pipes of differing diameters. This is important for maintaining a secure and tight fit that minimizes the risk of leaks.

Bell reducers create a smooth transition between different pipe sizes, facilitating effective flow of gas while ensuring that the connections are robust. Properly fitted reducers help in achieving the necessary seal and structural integrity needed in gas piping systems. Adequate sealing of joints is imperative since any leaks in gas systems can be hazardous due to the highly flammable nature of gases.

In contrast, the other options, while relevant to other piping applications, do not serve the same crucial purpose in joining gas pipes. Fittings like flared connections are typically used in situations involving liquid fuel applications, while cemented joints and concealed bushings do not provide the necessary flexibility and leak prevention attributed to bell reducers in gas installations.