Which component is critical for vapor recovery in Stage I systems?

The vapor balance line is a critical component in Stage I vapor recovery systems because it is responsible for capturing vapors displaced from the storage tank during the fueling process. When fuel is drawn from the underground storage tank, vapors that are generated must be managed to prevent them from escaping into the atmosphere, which contributes to air pollution and can create hazardous conditions.

The vapor balance line effectively allows these vapors to return to the storage tank instead of being released into the air. This system helps maintain atmospheric pressure in the tank and reduces emissions, aligning with environmental regulations designed to minimize pollution. The proper functioning of the vapor balance line is paramount to ensure that vapor recovery is effective and meets compliance standards.

In contrast, while the fuel pump, storage tank lid, and flow meter are all important components of the fueling system, they do not directly contribute to the management and recovery of vapors in the same way the vapor balance line does in a Stage I vapor recovery system.