Okay, you have one oiltank and want to install a second oiltank. We just put in another diesel tank here (3 in parallel) in the equipment yard, giving us a full 30,000 gallons of gasoline and 45,000 gallons of diesel. They are all 15,000 gallon fiberglass tanks. Usually, you can bury 1,500 without a permit, but Department of Ecology has a different set of rules from Building and Safety. Plumbing it was no big deal. Either way, your local Building and Safety Department will have strict legal requirements for installing new tanks and the plumbing hookup that they require. Also be sure that your local DOE will let you handle the job yourself. It's a soap opera in suburbs where your neighbors are on well and septic.
Diesel fuel hookups are NOT the same as home heating oil hookups. The main thing you have to worry about is ground water dispersal/confinement. Home heating oil, you must disperse the water through the oil. Diesel fuel for trucks and equipment, you must contain the water and pump it to a separation tank for DOE disposal: do not even think about plumbing that crud into a septic system as they will shut down your system, sell you a big nasty ticket, and then I'll cop an attitude because I don't like drinking diesel fuel. DO NOT PROCEED WITHOUT A PERMIT!!!!!!!!
You will need: a backhoe, 5-6 cubic yards of insulating grout (never install a steel tank without that protection -- code requires it) an explosion-rated 1/3 HP fuel circulating pump, sufficient 12-4G NM-B wire to reach your post or panel, as required, NM-B for inside the concrete box, 6' 3/4" gray PVC conduit w/ 2 sweeps, sufficient 3/4" gray PVC conduit to hook up the power to your pole of home, panel nut and lock, sufficient 2" malleable black iron pipe to reach between the tanks twice, and once to and from the surface, a 24" X 24" X 24" reinforced concrete box with sealed 2" pipe openings and 1" electrical opening, steel road-load rated lid, 4- 2" black dielectric connectors, 2- 2" black 90's, 50-gallon open-top discharge tank (the circulation pump has a water-expulsion feature) a pipe cutter-threader, 4-2" check valves, 3-vents, a new chute, and a spirit level that you actually trust.
I prefer my laser level for these jobs. It takes about 40-45 manhours to complete MOST installations, but with non-professionals, it can take a month of Sundays. Still, don't let it back you off: you own the land, so command it with pride.
1. Locate the infeed pipe (drop or chute as the distributors call them) and set a paint line fifteen feet all the way around the drop. That's where the tanker truck comes to fill the tank. Your tank should have 6" of grout around it but most of those I dig up don't. If your tanks don't have a circulating system, now is the time to install it, between your proposed tanks.
2. Using your friendly local backhoe, score a channel no more than a foot deep around the line. That sets your mark for the rest of the cutting you'll have to do. Cut the topsoil and save it. Now that you are in the subsoil, check for leakage. Simple test: put a small handful of the subsoil in a quart jar half full of water, remove any rocks, seal it, and shake it like you meant it. Put the jar aside for fifteen minutes. If you see ANY oil, or emulsion on top of the water, the tank is bad. The reason to go down at least a foot is because runoff or surface spillage from the delivery tanker will cause some contamination no matter what. Most DOE permits come with two nalgene bottles and test media already in the bottle. The shake test is for your benefit.
3. If you have an old steel tank, know that you probably have a rusted leak somewhere. If you have a newer fiberglass tank, then you're in good shape: I have yet to need to remove a glass tank. Either way, you're into an excavation.
4. Find the edge of the tank. Most residential oil tanks are either 750-gallon or 1,500 gallon. They come in various shapes and sizes. Cut a little deeper than the bottom of the tank, then get out your manual backhoe (a plain old shovel) to make the final trim cuts to expose the tank. If you have a fiberglass tank, it's brittle the minute you bury it. Steel tanks aren't much tougher. Repeat the leak test with soil that came from below the tank if only to convince your local safety officer that you complied with code.
5. Once you have a clean sample of soil above and below the tank, look on the side and bottom of the tank. You should find two bungs on either side of the tank that hook to dip tubes. They should be 48" apart. You will find six on all ASME-code tanks.
6. Make your next cut to fit the auxillary tank. NEVER fit a larger aux tank than the primary! If necessary, fit the larger tank with the pump feed, vent, and chute, hopefully new, on account of what that is the way she is did. Although you do not install chutes on auxiliary tanks, you DO install vents. Assure that you will have at least 48" of subsoil and 36" of topsoil on your new tank to assure proper soil support. Assure that the bungs will be level on installation of the second tank: if necessary, cut or fill to the proper height.
7. Set 6" of insulating base grout where the new tank will sit but leave room for the inspector to check your work. If you don't, he has the right to make you dig it up, which is definitely a pain. Watch with eager anticipationas he makes that lusted-after check mark on your permit, and then have a few beers because if you passed on the first try, it is a minor miracle.
8. Make any corrections the irate inspector commands.
9. Hook up the tanks with dielectric connectors. Install the check valves, assuring that one side flows in, the other side flows out, and that they all run in a circle. That is because you will need circulation. Check the pump to be sure that it has not locked up on you. Close the system, make a check-installation of the pump, and fire it up. If you hear air coming out of one vent and sucking in the other, you put in a check valve backwards. Correct that while the soil is open. The black pipe will ground itself but the tanks will still need grounding. Pull the pump and set the circulation tubes cut 12" shorter than the nominal surface.
10. Call for secondary inspection. You still have a final inspection ahead of you, so make sure the site is clean and safe. Once you pass secondary, grout the tanks, install the circ. pipes and cap them to prevent contamination. Fill to within 24" of the nominal surface, taking care not to damage the circulation pipes. Compact the soil every 36 inches. Set the concrete box over the circ. pipes, install the pump, hook up all the electrics to a 20-amp breaker, and test the system again. You should not hear sucking or blowing noises.
11. Call for final inspection. Once you pass, do the final grading, plant with whatever grass was on the lawn in the first place, return all the rental equipment, and fill the tanks with clean fuel. The circulation pump then fills your vehicles, runs the circulation system, and filters your fuel. In time, you will come to appreciate how much that system is worth, as all your neighbors come to you in times of need, begging for a tank of gas.
Isn't it nice to see people grovel?
