What is required for the marking of CNG service hose?

For the marking of CNG service hose, the requirement is that it must be continuously and distinctively marked. This means that the entire length of the hose should have markings that clearly identify it as being suitable for CNG service. Continuous and distinctive markings help ensure that anyone handling the hose can immediately recognize its purpose and compatibility without having to examine it closely at specific points. This clarity is crucial for safety and operational efficiency since improper use of hoses can lead to hazardous situations, including leaks or failures.

The other options either limit the visibility and recognition of the hose or do not provide sufficient identification. For example, marking only at connection points would not ensure that the identity of the hose is clear throughout its entire length. Similarly, marking in a single color may not provide enough information regarding the specific type of gas the hose is designed to carry, and using reflective materials, while enhancing visibility in low light, does not directly pertain to the identification requirement for service hoses.