Which material is acceptable for pressure containing parts in a CNG system?

The use of steel, ductile iron, or brass for pressure-containing parts in a compressed natural gas (CNG) system is vital due to the high-pressure conditions that these systems operate under. These materials have the necessary strength and durability to withstand the significant forces exerted by CNG, ensuring safety and reliability in the system.

Steel is commonly utilized because it possesses high tensile strength and can handle the pressures associated with CNG. Ductile iron offers excellent resistance to fracturing and has good mechanical properties that are advantageous in pressure applications. Brass is also a good choice because it has corrosion resistance and can handle moderate pressure applications effectively.

In contrast, materials like plastic and fiberglass typically do not have the structural strength required for pressure-containing components in high-pressure systems like those used with CNG. While some advanced polymers may be developed for specific applications, they are generally not suitable for handling the pressures encountered in CNG systems. Using aluminum can present challenges as well; while it is lightweight, it's not as strong as steel or ductile iron under high pressure, which may lead to failures. Therefore, the selection of steel, ductile iron, or brass is the most appropriate choice to ensure safety and efficacy in pressure-containing applications in a CNG system.