Can you rely solely on an OPD valve for accurate filling of a DOT cylinder?

When discussing the reliance on an OPD (Overfill Prevention Device) valve for accurately filling a DOT (Department of Transportation) cylinder, the correct choice highlights that while OPD valves play a role in the filling process, they are not intended to provide complete assurance of accuracy on their own.

OPD valves are designed primarily for safety by preventing overfilling and ensuring that the cylinder does not exceed its fill limit. They work by stopping the flow of the liquid when the proper fill level is reached, which is crucial for preventing hazardous situations while handling gases. However, they do not provide measurement or calibration of the amount being filled; their function is more safety-oriented than measurement-oriented.

Accurate filling of a DOT cylinder requires proper gauges and adherence to procedural standards to ensure that the correct volume and pressure are maintained. Therefore, relying solely on an OPD valve does not account for the necessary monitoring and calibration that should accompany the filling process. Thus, while OPD valves assist in the filling by preventing overfills, they do not serve as the sole mechanism for ensuring that the cylinder is accurately filled, making the selection of the correct answer appropriate and justified.