Oil Tank Fill & Vent Piping Elbow & Bend Limitations

Above: inside the same building as shown at page top, we see a very simple and effective piping arrangement: both fill and vent pipes rise vertically from the oil storage tank and make a single 90 degree bend to extend outside through the building's foundation wall.

Below in our photograph, an oil fill pipe at a property in Dunedin, New Zealand (South Island) doubles back on itself to give the oil delivery driver a fighting chance at filling an oil tank that is uphill from the point of fill.

To me [DF] this is a rather ugly installation that seems likely to lead to a spill.

Reader Question: elbows in oil tank fill & vent piping

2015/11/25 Ron said:

How many elbows are code on a fill or vent pipe and if you have too many can it cause a vacuum

Reply: oil storage tank fill & vent piping specifications & codes vs number of bends or elbows

Ron, I have not seen an explicit limit on elbows on oil tank fill or vent piping, though one would want to keep the number to a minimum. Using the ICC as adopted by New York City as the 2008 NYC Mechanical Code, an example we have this:

1305.6 Fill piping.

Fill piping shall comply with the requirements of Sections 1305.6.1 through 1305.6.6.

1305.6.1 Size.

Fill piping shall be a minimum of 2 inches (51 mm) in diameter or 3 inches (76 mm) for No. 6 fuel oil.

305.6.2 Termination location.

A fill pipe shall terminate outside of a building at or above grade at a point least 2 feet (610 mm) from any building opening and 5 feet (1524 mm) away from any subway grating at the same or lower level.

A fill pipe shall terminate in a manner designed to minimize spilling when the filling hose is disconnected.

Where No. 6 fuel oil is used, the fill pipe terminal shall be within 3 feet (914 mm) of the curb unless otherwise required by the Department of Transportation or the Transit Authority.

If facilities exist for an oil delivery truck to drive onto the premises, the fuel-oil terminal may be located elsewhere other than the curb.

1305.6.3 Separate fill piping.

Each storage tank shall be provided with a separate fill pipe, except that where a battery of tanks containing the same grade of oil is installed, a common fill and header pipe may be installed.

Also see NFPA 31 that governs oil tank installation & piping that has similar language:

From NFPA31 as adopted by Warren Co VA cites the fittings and tubing requirements for oil fill & vent pipes:

NFPA 31 section 8.2.5

Pipe shall be connected with standard fittings and tubing with fittings of listed types.

On 2013-03-10 - by (mod) - details on oil tank piping routing and bends

Thanks for the update, Tony. Sometimes it takes a few minutes for a posted comment to find its way through the spam filters.

Even if you could get a flexible PVC tube down into the oil tank (which can be done on some piping arrangements) without a procedure for keeping the tube dead straight you would not get an accurate reading.

About oil tank gauge accuracy, because of the shape of the tank the gauge will generally never be able to be precisely accurate except at 3 points:

Full
Half Full
Empty (Even "empty" may leave a bit of oil in the tank).

I'd consider the gauge more as an indicator of when to ask for an oil delivery if you're not on automatic delivery (which I prefer). If the gauge is at 1/4 tank or below you'd best give the oil company a call.

For applications where a more accurate oil tank gauge is really needed there are some after-market devices that use electronics and are more consistent.

On 2013-03-10 by Tony

Apologize for the multiple posts.. kept clicking as it would not display[ thank you for your comment..
sorry/

On 2013-03-10 by Tony /Please disregard previous

Ok... found out the Problem.. Before the Fill pipe goes into my tank, it screws into a "90'
and and another small pipe comes out the other end of the 90 then into the tank.

so, i'M hitting the pipe threads on the "other end [inside the pipe]."...also, my tank is in a dark area of my basement so I never noticed that there is another threaded access port on the far end I assume giving you a choice of connecting your fill pipe to either side.

There is a square cap covering that port so with a Pipe wrench I should be able to check oil lever from there pretty easy.
Ok. last and helpful question.

Pretty sure my tank is 275 gallon. dimensions are:
60" long/ 44" high[on legs but only measured the tank], and 23-24" wide.. can u tell me how many inches equals how many gallons...? seriously finished here.. thanks.

On 2013-03-09 by Tony

hi again,
sorry fro all the mis-spells.. I was in a hurry and should have proof read before I clicked
" Comment".

On 2013-03-09 by Tony - inaccurate oil tank gauge - measure oil through filler pipe?

My heating oil tank is in my basement. my gauge is not accurate. I attempted to measure my oil level from the outside filler pipe.

I bought a piece of flexible PVC pipe barely half inch diameter and marked off every 6 inches on the pipe. My outdoor filer pipe goes thru my basement wall about a foot then a slight bend downward into the top of the oil tank.

my problem is I can't get the pipe any further than about 12 inches. It feels like there is an obstruction right before the pipe goes into the tank..[275 gallon].

Is there something in a filler pipe like what would be in a bathtub drain to keep debris from getting into your tank[ example; maybe kids dropping a stone or something into your fill pipe?

I can not get thru any more than a foot before I hit something that is stopping it. btw: tank is in full use. Oil was dropped off thie week]... thanks for any input.