California ICC UST Inspector Practice Exam

Where is an emergency impact valve (shear valve) typically located on a UST System?

1. At the turbine piping termination

2. Base of the dispenser

3. Under the extractor tee

4. In the spill container

The correct answer is: Base of the dispenser

An emergency impact valve, also known as a shear valve, is typically located at the base of the dispenser. This positioning is crucial for safety and effective emergency response in the event of an impact or damage to the dispenser system. The shear valve is designed to close off the flow of fuel in case of a sudden force that could cause a break in the piping system, thereby preventing leaks and potential environmental contamination or fire hazards. When an impact occurs, the valve's design allows it to shear off and stop the flow of fuel instantaneously. The base of the dispenser is an ideal spot for these valves because it is directly connected to the fueling system, making it the first point of contact where pressure can be applied during an emergency situation. This location ensures that fuel does not continue to flow unchecked, thereby enhancing the safety measures in place within the underground storage tank system. Other locations like the turbine piping termination, underneath the extractor tee, or inside the spill container might house various other components, but they do not provide the same immediate response to an impact incident as the base of the dispenser does. The strategic placement of emergency impact valves at the base of the dispenser underscores the importance of rapid containment and safety in UST systems.