What is the maximum allowable pressure for a storage tank and vent system?

The correct choice regarding the maximum allowable pressure for a storage tank and vent system is 3 PSI or the manufacturer's maximum, whichever is greater. This standard is rooted in safety regulations and best practices to ensure that the storage tanks are not subjected to excessive pressure, which could lead to catastrophic failure or leakage.

By stipulating "3 PSI or manufacturer's maximum," the regulation allows for flexibility, recognizing that certain tanks may be designed to handle pressure above the general standard of 3 PSI. Therefore, if the manufacturer's specifications provide a higher maximum acceptable pressure, that would take precedence to ensure safe operation.

This approach promotes reliability and safety in storage systems, allowing each manufacturer's guidelines to dictate the specific limits while maintaining a baseline safety standard applicable to all systems.