What type of materials can be classified as substandard or illegal connection materials?

Brass fittings are commonly regarded as reliable and durable for gas piping applications; however, their use can sometimes be limited based on specific codes and standards. If there are regulations in a given jurisdiction specifying that brass fittings should not be used for certain types of gas connections—often due to potential corrosion or compatibility issues with other materials—then using them inappropriately could indeed classify them as substandard or illegal connection materials.

In contrast, high-grade stainless steel is recognized for its strength and resistance to corrosion, making it suitable for various gas applications. Pressurized PVC piping is generally not allowed for gas applications due to its inability to withstand high temperatures and pressures associated with gas. Steel casings, while typically sturdy, can also have restrictions based on their intended use and the type of gas being transported. Thus, the context of regulations and material compatibility plays a critical role in determining if certain connection materials are deemed substandard or illegal.