Texas Compressed Natural Gas (CNG) Delivery Truck Driver Practice Exam

Cylinders and pressure vessels used for storing compressed natural gas (CNG) are required to be constructed from materials that can withstand high pressure and offer durability and safety. Steel and aluminum are commonly used due to their strength and ability to resist the pressures involved in storing gas. Composite materials, which often consist of a mix of fibers and resin, provide a lightweight alternative while maintaining the required strength-to-weight ratio. The use of these specific materials is important because they are engineered to handle the mechanical stress and potential corrosiveness associated with compressed gases, ensuring safer transport and usage. Other materials, such as plastic or wood, do not possess the necessary structural integrity to handle the demanding conditions found in CNG applications. Thus, option B correctly identifies the appropriate materials for these safety-critical components.