Filling tank off of another tank with sub pump.

[cstoredude]

Sounds like they have just been "getting away with it" to me.

[mwtoupin]

I build fuel systems for E-gen systems. This is a typical scenario for those systems but the comment about AST's having an E-vent is the key. There is no way that can get plugged and cause the tank to become over pressurized. UST's, even steel ones, are not capable of withstanding the pressure that could build in a vent failure scenario. One of your questions was about the overfill tube, and yes there are pressure overfill drop tubes for this type of tank fill. But I am 99.99% sure they are not listed for UST installations because the tank could over pressurize before the tank is full and they shut off the inflow. So in my opinion this is a formula for disaster and consequently would refuse to build it unless there is some type of failsafe overpressure protection built in, i.e. an emergency vent.

[cstoredude]

Obviously this is an illegal practice, without question.

UST manufacturers state DO NOT PRESSURE FILL.

Federal regulations require installers to comply with manufacturer installation guidelines.

The real question is when will a regulator stand up and enforce these regulations?

If they can choose not to enforce these regulations, why can they enforce any of them?

[hardworking]

While I love to be a "field engineer", this (IMO) requires a PE to design the system. There are many considerations (as the members have stated) and a PE would carry the insurance for design mistakes that a petroleum contractor most likely would not.

[Petrosell]

Im doing this now in The BAHAMAS at a marina I have a client whom I installed 4 12ks 10 yrs ago . He just bought 2 more 25k tanks from me as he wants to increase capacity. The new tanks will have submersible pumps plumbed into the existing tanks for transfer . The existing tanks will have mech shut off valves.
The transfers will be completed with a custom control box I had built. The box has timers , e stop, hi level alarms and lights and also low level alarms .
The entire farm will get a new 450 plus also. To set up a transfer he can input a time say 30 minutes for each tank and product.
The pumps will run 30 minutes or whatever time he inputs. If the existing tank gets full a hi level alarm sounds at 90 % , if the level gets to 95% the panel will shut off the pump and the mech overfill will be shutting down the fill. Also if the supply tanks get to low the the submersibles are also shut off to protect the subs. Also the panel has a manual push button pump override if you want the pumps to run in alarm conditions.

[Techie]

I believe if your system was piped out according to local codes, you could transfer fuel as if they were manifolded tanks, A Veeder-Root system with pump control modules could fill tanks according to fuel level automatically. You could be protected by installing plld sensors in slave tanks and setting up a plld disable alarm that would completely shutdown slave submersibles by disconnecting power to remote submersible pumps. There are ways to do this safely, Pipe accordingly.

[bigbadjohn]

I think the the bypass button is a huge mistake. Designing in layers of safety and redundancy is a waste of time when the first guy presses the button because he knows he's smarter than the system.

If you really want to go this route, use a key switch feeding a timed relay. That way every flick of the switch will only run the system for a short period of time (I'd recommend 3 to 5 minutes). Forces the operator to stand there and watch what's going on. Keep the bypass key in a combination lock box and the operator will have to call senior management to get the combo, they can log the event and decide if he really needs to enter bypass. Every time they use the key you can change the combination.

[sdisselhorst]

Wrong. The only safe and legal way to fill a UST is gravity drop.

That's why the UST manufacturer's state it in their manuals.

(Mike drop)

[stuppid]

We need a like button.