Which feature is essential for the design of CNG cylinders?

CNG cylinders are specifically designed to store compressed natural gas at high pressures, typically around 3,000 to 3,600 psi. This high-pressure capability is essential for the safe storage and transport of CNG, allowing it to be stored in a compact form that makes it practical for use in vehicles and other applications. The material and structural integrity of these cylinders are critical, as they must withstand significant stress and prevent leaks or ruptures.

The requirement for high-pressure resistance is not just about performance but also about safety; cylinders must adhere to strict regulatory standards that ensure they can handle the pressures involved without risk of failure. This feature underpins the overall functionality and reliability of the CNG system, making it the foremost consideration in the design of these cylinders.

While lightweight materials can be beneficial in making the cylinders easier to handle and install, and a smooth outer layer may aid in manufacturing processes or aesthetics, these factors are secondary to the fundamental need for strength and durability under pressure. Transparency is not a required feature for CNG cylinders, as their primary function is related to containment of gas, not visibility.