How does a non-restricted OPD affect the filling of an ASME tank?

A non-restricted OPD (Overfill Prevention Device) is designed to help prevent the overfilling of cylinders during the propane filling process. If an ASME (American Society of Mechanical Engineers) tank incorporates such an OPD, its function can directly impact the filling process. Specifically, the presence of a non-restricted OPD may lead to the filling process being halted prematurely.

This occurs because the OPD is configured to sense when the liquid propane reaches a certain level within the tank, effectively stopping the fill before reaching full capacity to prevent overflow. As a result, if there is insufficient consideration of the tank’s fill level or the way it is being filled, the OPD could trigger an early stop in the filling operation, potentially leading to less propane being filled than the tank’s maximum capacity.

The other responses focus on aspects of filling that do not apply to non-restricted OPDs. The OPD does not inherently allow for faster filling, nor does it serve to regulate pressure more effectively. Additionally, while it does work to prevent overfilling, that is a specific function rather than a direct effect on how the fill process itself is conducted—hence why stating it may stop the fill process prematurely encapsulates the OPD's effect