The discharge of the regulator vent for an underground container must be above what level?

The discharge of the regulator vent for an underground container must be above the highest portable water level. This requirement is in place to ensure that if there is a release of gas, it can vent safely to the atmosphere without becoming an issue in the event of flooding or water accumulation. If the vent were to be positioned below the highest portable water level, there is a risk that water could enter the vent system, potentially creating a hazardous situation due to the inability of the gas to vent properly.

Maintaining the vent above this level allows for proper functioning and safe operation of the system, which is paramount in preventing accidents and ensuring public safety. Other options, while relevant to various safety standards, do not specifically address the critical concern of water ingress into the vent system in a flood scenario. Therefore, ensuring that the vent is set above the highest portable water level is essential in compliance with NFPA 58 standards for storage and handling of Liquefied Petroleum Gas (LPG).