TCFP Plans Examiner Practice Test

What is the main purpose of vents in underground storage tanks?

1. To allow airflow for evaporation

2. To prevent pressure build-up

3. To keep contaminants out

4. To allow for temperature regulation

The correct answer is: To prevent pressure build-up

The main purpose of vents in underground storage tanks is to prevent pressure build-up. When fuel or other liquids are added to or removed from the tank, the volume of liquid changes, creating pressure variations within the tank. Without proper ventilation, pressure can increase to dangerous levels, potentially leading to tank damage or even catastrophic failure. Venting provides a pathway for vapors and gases to escape, thereby maintaining the necessary atmospheric balance inside the tank. This is essential for both safety and the integrity of the tank structure. Proper venting also helps to reduce the likelihood of leaks and environmental contamination caused by ruptured tanks due to excessive pressure. While airflow for evaporation, contaminant prevention, and temperature regulation are important considerations in tank design and operation, the primary role of vents is to manage pressure changes effectively. This focus ensures both safety and compliance with regulations regarding underground storage tanks.