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when an oil tank fails...

I've just moved into a house with a very rusty oil tank in the basement. I don't know its age or manufacturer.  It looks like the tank has been patched at some time in the past.   I'm hoping I can get through the winter with it, giving me a chance to learn about my steam system (a first for me) with its 20yo Weil McLain 68 series boiler and to interview contractors about a possible conversion to gas.  So my question is: when an oil tank fails, does it typically just start to leak or does it sometimes fail catastrophically?  If it just leaks, could I put a drip pan under it and hobble through the NY metro area winter?  I know I'll need to either replace the tank or switch to gas in the foreseeable future, but I'm trying to buy some time now while I educate myself.

Many thanks.



  • STEVEusaPASTEVEusaPA Member Posts: 4,412
    yes....and I wouldn't

    Tanks usually fail 2 ways.....first you'll notice staining around the bottom, where the water and all the other sludge hangs out, then some dripping.

    But the other, worse way is, when you get a delivery into that weak tank, and the driver blasts it in at 90 gallons a minute, with an undersized vent, pressuring the the tank, then catastrophe is an understatement.

    And, at best it will make a huge mess.  At worse, it will destroy your whole house, and that's not considering the environmental impact.

    A drip pan isnt worth the effort.  First of all, if it's leaking you gotta yank it.  Secondly, if there's any oil in the tank just trying to lift it will probably puncture the weakened bottom of the tank.

    I would replace the tank.  Theres so much at risk.  Besides, if you switch to gas, you can use up or pump out the oil, and probably resell the tank.

    I also would go with a double wall tank, with leak detection, like a ROTH tank.  Not much more expense for the peace of mind.
  • jv100jv100 Posts: 56
    Thanks, Steve!

    Wow, I hadn't thought about that failure-on-tank-filling scenario!  Very scary. Seems quite plausible, though.  Thanks for the idea about reselling a newer tank.  I'll look into the ROTH tanks.
  • Alan R. Mercurio_3Alan R. Mercurio_3 Member Posts: 1,617
    Re: when an oil tank fails...

    I agree with Steve. And I’d like to add that I work here in NY and I can tell you the cost of a clean-up and possible fines from the DEC far exceed the cost of a new tank installation.
    Your friend in the industry,

    Alan R. Mercurio
  • jv100jv100 Posts: 56
    Thanks, Alan!

    Good point about the DEC fines, etc.  A major failure would be a costly nightmare.  Okay, I'm definitely not going to risk using this tank. Now I just have to decide whether I should replace the tank in the hopes that my old boiler will make it a few more years or dive into a gas conversion...

    Thanks again, all!

  • Alan R. Mercurio_3Alan R. Mercurio_3 Member Posts: 1,617

    You're very welcome!
    Your friend in the industry,

    Alan R. Mercurio
  • BobCBobC Member Posts: 5,127
    edited August 2011

    I remember a lot of grief years ago when people noticed that the ethanol in gas was attacking fiberglass tanks in boats. I know new fiberglass tanks are fine with it but some older tanks essentially slowly dissolve because of it. Diesel oil does not contain ethanol yet but it would not surprise me to find the furry little regulation gnomes are working overtime to fix that.

    Newer fiberglass boat tanks are fabricated so ethanol won't affect them but I would get written verification from the manufacturer before installing a fiberglass tank. Here's a portion of the article about those tanks. You don't want to learn that lesson all over again because someone did not consider what might get added to diesel 9or #2 fuel oil) in the future.

    In the 1980’s a few boat builders were building fiberglass tanks into their boats. They were using the polyester resins that were commonly used at the time. At that time it was not known that alcohol could have a corrosive affect on fiberglass. It was known then, as it is now, that gasoline itself can dissolve fiberglass laminates, but if the builder used resins that were resistant to gas, and gel coated the tank, it was thought that it would not be affected. Unfortunately they were wrong.

    A few years ago there began to be reports of fiberglass tanks failing. Over the last few years the trickle became, if not a flood, a running stream. The Boat Owners Association of the US (BOATUS) commissioned a laboratory to do testing of fiberglass tanks and found out the alcohol can dissolve the resins in the laminate. As we now know, fiberglass is not impermeable, as had been thought back in the 60's and 70's. When boats began blistering in the 1980’s, the Coast Guard and others began studies to find out what was going on. To make a long story short, fiberglass reinforced plastic or FRP, is actually a semi-permeable membrane and liquids will penetrate the resins. This is what led to blistering. Alcohol will penetrate FRP as well and dissolve uncatalyzed resins. That is, resins that were not mixed well with the catalyst and never set up. If alcohol dissolves these then eventually the damaged will be extensive enough that the laminate will fail. This does not happen overnight. It takes years, and it takes long exposures to alcohol. Boats typically sit for long periods of time with full fuel tanks, allowing the components of the fuel to do the damage. This has not been seen on automobiles or trucks because fuel simply does not sit in the tank and system for very long. However, the research shows that the potential exists for tanks to be damaged in a short time span, 6 months to a year, depending on the laminate, the resins used and how well the FRP laminate was made. But almost all of the tanks that have been reported as leaking have been built in the 1980’s or earlier.

    The full text is attached or can be accessed here -

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • jv100jv100 Posts: 56
    Thanks, SLO-115!

    Given the other history I know about the house (long story), I'm guessing the tank was run close to dry, and I'll bet there is lots of slug in there.  I didn't know about the fiberglass tanks, so I'll explore that option also.  Thanks also for mentioning the top connection.  I never would have thought about that issue because my current tank lies on its "side" and is up on legs, with the valves,etc hidden or out of reach.  So much to learn!
  • jv100jv100 Posts: 56
    Thanks, Bob!

    Interesting article.  It's often tempting to go with a new technology, but as that article points out, sometimes the downsides of that new technology doesn't show up until years later. Such is the risk of progress!  I'll keep this article in mind as I do my research.
  • billtwocasebilltwocase Member Posts: 2,385
    I think

    He is now afraid of oil heat?  All he needs is a competent full service oil company, and have the tank inspected. Tanks don't just open up and spill everything out unless someone is not following some simple common sense steps before, during, and after filling the tank. If it is a leak due to a spotty thin bottom, it will drip and generally seal itself back up. A magnetic patch can usually seal it until it is replaced. Oil heat is safe, I thought he missed that message somehow.
  • jv100jv100 Posts: 56
    Thanks, billtwocase!

    No, not afraid of oil heat at all.  I've had oil heat in most of the houses I've lived in, and those tanks were underground.  And I always try to have things fixed before I give up on them.  But tank really is in bad shape and at the end of its useful life, I'm quite certain.  Thanks for the thoughts, though. 
This discussion has been closed.


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