Typically, vapor return piping is connected to which type of tank?

The correct answer is that vapor return piping is typically connected to the lowest grade gasoline tank. This connection is essential in the operation of vapor recovery systems because the lowest grade tank tends to be the most volatile in terms of its vapor emissions. By connecting vapor recovery piping to this tank, operators can effectively manage the vapors produced during the refueling process, preventing them from being released into the atmosphere.

This approach helps maximize recovery efficiency because lower grade fuels usually have higher Reid vapor pressures, which result in more vapor generation during both storage and dispensing. Managing these vapors is critical for pollution control and compliance with environmental regulations.

Vapor recovery systems are designed to capture these volatile organic compounds (VOCs) to mitigate air quality issues, and having the vapor return piping connected to the lowest grade gasoline tank ensures that the system can perform its function optimally. Therefore, understanding the characteristics of each type of fuel and its grades is vital for the correct implementation of vapor recovery systems.