YQA Fuel Tank Fill Systems

06.01 How are underground tanks typically filled?

Undergound tanks are typically filled by gravity drop from delivery trucks. Delivery hoses are connected to the tank fill pipe with a tight-fill connection at an in-ground spill containment sump. The underground tank fill pipe includes an overfill prevention valve that closes at 90% of tank capacity.

06.02 Can remote fill point be used for underground tanks?

Remote fill pipes can be used for underground tanks and are typically used where (a) the underground tank location does not allow for delivery truck access, and (b) where underground tanks are located in secure fenced areas where delivery trucks are not allowed for safety and security reasons.

Remote fill pipes need to slope toward the tank, and for longer piping runs the tank burial depth needs to be evaluated to accommodate the slope.

06.03 How are aboveground tanks filled?

Aboveground tanks are filled by several methods:

(a) delivery tuck is pump equipped and the delivery nozzle is directly attached to a top of tank fitting. Access stairs and platforms are typically provided for safe personnel access to the top of the tank. This system has the benefit of simplicity and the drawback of safety issues associated with moving heavy fuel hoses up stairs or ladders.

(b) delivery truck is pump equipped and the delivery hose is connected to a fill pipe at a ground mounted spill container. This system provides for personnel safety while increasing the complexity of the fill system.

( c) delivery truck is gravity drop and a stationary transfer pump mounted at grade moves fuel from the truck to the aboveground fuel tank through the fill pipe. This system has the benefit of being able to utilize the broader availability, and sometimes lower cost, of gravity drop fuel trucks. The drawback is the capital cost of providing the stationary pump system.

06.04 How is a tank within a building filled?

Tanks in buildings have the challenge typically of being remote and blind from the fill point, increasing the importance of safety controls. Tanks in buildings are required to be located on the lowest level, usually in basement level or at grade. Gravity flow to lower level tanks may be used where appropriate, however typically fuel is pumped from outside fuel receipt points to the tanks.

Fuel piping systems from outside fill stations to tanks in buildings are typically double contained for safety.

06.05 What accessories are needed for tank fill systems?

Required accessories for tank fill systems are as follows:

(a) tight fill connection for delivery hoses which are usually camlock type connections to minimize spills.

(b) spill containment devices surrounding the fill pipe connection to the delivery hose.

(c ) overfill prevention valve in the fill pipe. This would be either a mechanically actuated float type valve, or an electrically actuated valve that closes at 90% fill level.

(d) high level sensors in the fuel tank for high level alarm activation.

(e) a high level alarm device providing visual and audible indication.

(f) a means of determining the fuel level in the tank such as an electronic level gauge.

(g) a secondary means of determining the fuel level in the tank such as a manual gauge port.

(h) safety equipment including spill cleanup kits and fire extinguishers.

(i) manual shutoff valves and check valves for aboveground tank systems.

06.06 How do you fill multiple tanks from a common fill station?

There are 2 methods of filling multiple tanks from a common fill point:

(a) individual fill pipes are run from each tank and they terminate within an enlarged fill station. This method has the benefit of simplicity but the drawback of increased costs for multiple fill points. Also within buildings the space requirements fro multiple fill points may not be practical.

(b) a common fill pipe with electrically actuated valves to allow tank selection and a control panel at the fill station to allow tank selection and high level alarm and shutoff.

06.07 What are the regulatory requirements for filling tanks?

Regulations for filling tanks are designed to prevent spills and overfills. Tanks required to have redundant protection for overfills such as a high level alarm plus a mechanical shutoff device. Tank fill limits are typically 90% maximum, although some locations may allow up to 95% for aboveground tank systems.

06.08 How do I size the fill pipe?

Fill piping for gravity fill systems is typically either 3” or 4” diameter.

Fill piping for pumped fill systems (either delivery truck pumps or stationary pumps) is generally sized as follows:

  • 2” pipe for flow rates to 100 GPM
  • 3” pipe for flow rates to 200 GPM
  • 4” pipe for flow rates to 300 GPM