What method should be used for making changes in direction of gas pipe?

When making changes in the direction of gas piping, the recommended method is to use fittings, factory bends, or field bends. This approach is preferred because it allows for a smooth transition in the flow of gas, reducing the risk of turbulence and potential pressure drops in the system.

Fittings are specifically designed to connect sections of pipe at various angles, while factory bends are pre-manufactured to provide consistent radius bends that ensure optimal flow characteristics. Field bends can be created on-site, allowing for a customized fit to accommodate specific layout needs while still maintaining integrity in the gas flow.

Using flexible tubing or standard elbows is often not ideal for gas applications, as they may not provide the necessary level of support and safety required for gas lines. Additionally, flat fittings do not offer the capability of changing direction effectively, which is crucial in gas piping systems to prevent leaks or other hazards. Therefore, the combination of fittings, factory bends, and field bends ensures that the gas piping is both functional and compliant with safety standards.