If a single dispenser supply tank with a water capacity of more than 4,000 gallons is filled using a liquid transfer line that is ______ or larger and a pressure equalizing vapor line that is _______ or larger, a transfer bulkhead, emergency shutoff valves (ESV) and one or more remote shutdown stations are required

If a single dispenser supply tank with a water capacity of more than 4,000 gallons is filled using a liquid transfer line that is ______ or larger and a pressure equalizing vapor line that is _______ or larger, a transfer bulkhead, emergency shutoff valves (ESV) and one or more remote shutdown stations are required

• A. 1 1/2'' and 1 1/4''
• B. 2'' and 1''
• C. 1'' and 1/2''
• D. 2 1/2'' and 1''

Answer: (A)

When transferring propane into a large dispenser supply tank, safety features are required based on how big the transfer lines are. The rule says that if the liquid transfer line is at least 1.5 inches in diameter and the pressure-equalizing vapor line is at least 1.25 inches, a transfer bulkhead, emergency shutoff valves, and one or more remote shutdown stations must be installed. The reason is that larger lines allow higher flow, which increases the potential amount of propane released in a leak or the speed at which a leak could propagate. A transfer bulkhead helps contain leaks and separate the liquid and vapor paths to improve containment and control. The emergency shutoff valves and remote shutdown stations give you the ability to quickly stop the transfer from a safe location, reducing exposure and limiting the amount of propane that could be released if something goes wrong. If either line is smaller than its threshold, those specific safety features aren’t required by this rule, because the risk from smaller-diameter lines is lower. The given sizes—1.5 inches for the liquid line and 1.25 inches for the vapor line—meet both criteria, which is why this combination triggers the requirement for the bulkhead, ESVs, and remote shutdown stations.

When transferring propane into a large dispenser supply tank, safety features are required based on how big the transfer lines are. The rule says that if the liquid transfer line is at least 1.5 inches in diameter and the pressure-equalizing vapor line is at least 1.25 inches, a transfer bulkhead, emergency shutoff valves, and one or more remote shutdown stations must be installed. The reason is that larger lines allow higher flow, which increases the potential amount of propane released in a leak or the speed at which a leak could propagate. A transfer bulkhead helps contain leaks and separate the liquid and vapor paths to improve containment and control. The emergency shutoff valves and remote shutdown stations give you the ability to quickly stop the transfer from a safe location, reducing exposure and limiting the amount of propane that could be released if something goes wrong.

If either line is smaller than its threshold, those specific safety features aren’t required by this rule, because the risk from smaller-diameter lines is lower. The given sizes—1.5 inches for the liquid line and 1.25 inches for the vapor line—meet both criteria, which is why this combination triggers the requirement for the bulkhead, ESVs, and remote shutdown stations.