Which component must meet specifications provided by the cylinder manufacturer for CNG service?

The component that must meet specifications provided by the cylinder manufacturer for CNG service is the pressure relief devices. These devices are critical for safety and ensure that the pressure in the cylinder does not exceed a certain limit, which could potentially lead to failure or an explosion. Pressure relief devices are designed to activate at specific pressure thresholds, allowing excess gas to escape safely and helping to maintain the integrity of the cylinder. They must adhere to the manufacturer's specifications to ensure they are appropriate for the specific cylinder design and gas type, guaranteeing reliable performance under varying pressure conditions.

In contrast, while the fuel supply lines, compression pumps, and fuel injectors are important components of a CNG delivery system, they do not directly relate to the specifications set by the cylinder manufacturer in the same way that pressure relief devices do. Fuel supply lines must be compatible with the CNG and properly rated for pressure, but they don't have the same direct specification mandates as the pressure relief devices. Compression pumps also need to adhere to general safety and performance standards, but these are not specific to cylinder manufacturers. Fuel injectors function to deliver gas to the engine but again do not have specifications that are dictated by the cylinder manufacturers.