What are the two main types of vapor recovery systems?

• A. Stage I and Stage III
• B. Stage II and Stage IV
• C. Stage I and Stage II
• D. Stage II and Stage V

Answer: (C)

The correct answer identifies the two main types of vapor recovery systems as Stage I and Stage II.

Stage I vapor recovery systems are designed primarily to prevent the emission of vapors during the transfer of fuel from a delivery vehicle into storage tanks at fuel dispensing facilities. This system captures vapors that would otherwise escape into the atmosphere, especially during the tank filling process.

Stage II vapor recovery systems, on the other hand, focus on recapturing vapors displaced during the fueling of vehicles. This occurs at the nozzle of the fueling station, where vapors created as fuel fills the tank are drawn back into the storage tank, further minimizing air pollution.

These two stages are critical because they represent the foundational elements of vapor recovery technology utilized in gas stations and refineries to mitigate environmental impacts related to volatile organic compounds (VOCs).

The other options are not correct because there are no recognized Stage III, Stage IV, or Stage V vapor recovery systems within the context of standard vapor recovery classifications. The terminology and classifications are well-defined, and understanding Stage I and Stage II is essential for anyone learning about vapor recovery practices.