Compressed Natural Gas (CNG) Certification Practice Exam

The minimum rated service pressure for fuel supply cylinders at 70 degrees Fahrenheit is 2,400 psig. This rating is critical for ensuring the safe containment of compressed natural gas (CNG) under varying temperature conditions. The determination of minimum service pressure is dictated by industry standards and safety regulations, which take into account the properties of CNG and the potential pressures that can occur as temperatures rise.

At 70 degrees Fahrenheit, a pressure rating of 2,400 psig provides sufficient safety margins for materials and construction techniques used in cylinder manufacture. This ensures that the cylinders can withstand pressure fluctuations that may occur during operations without risking safety or structural integrity. Compliance with these pressure ratings is essential for reducing the risk of accidents and ensuring compatibility with fueling systems designed for CNG.

Higher ratings, such as 2,800 psig or 3,000 psig, while acceptable for certain applications, are not the minimum required service pressure needed for safe operation at this temperature. Thus, the selection of 2,400 psig as the correct answer reflects the balance between safety, compatibility, and operational efficiency for fuel supply systems.