Oil Tank Fill & Vent Piping Elbows & Swing Joints

Elbow & Bend Limitations
Swing Joint requirements

Elbows & Bends in Oil Tank Fill & Vent Piping

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.

Oil storage tank fill & vent piping specifications & codes vs number of bends or elbows

We have not found 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:

Mechanical Code 1305.6 [Oil Storage Tank] 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.

Inaccurate oil tank gauge - Can I 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 through 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 through any more than a foot before I hit something that is stopping it. BTW: tank is in full use. Oil was dropped off this week]... thanks for any input.

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.

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 ? - On 2013-03-09 by Tony -

Reply: Details on oil tank piping routing and bends

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.

Swing Joints in Oil Tank Fill & Vent Piping?

Definition: Swing joints on fuel piping are a technique for providing flexibility at various points in an underground piping system by making up joints composed of steel 90-degree elbows and nipples. (PEI 2025)

Requirement: swing joints on residential oil tank fill and vent piping are normally not required but there may be exceptions, as we'll explain below.

Details:

Swing joints in piping systems (for other readers) are a combination of pipe elbows that allow piping to tolerate movement, such in underground piping systems, or where they are needed to align pipes that otherwise don't line-up.

Bottom line: swing joints are not a specific requirement in most oil tank installations.

Where Are Swing Joints or Equivalent Flexible Joints Used in Oil Tank Piping?

On occasion we've seen swing joints used to align an existing oil tank fill and vent pipe with the installation of a new or replacement oil storage tank. The installer may find it easier to use a combination of pipe elbows and nipples to join oil fill or vent lines than to move either the oil tank or existing fill and vent pipes that may have already been installed through the building wall.

Really? Well yes, but at OIL TANK REPLACEMENT PROCEDURE you'll see that the installer made a neat clean oil tank installation by shifting the new oil tank so that its fill and vent pipe openings aligned neatly with the existing fill and vent pipes through the building wall.

However if a residential oil tank is installed in an earthquake zone then your state, provincial or local codes might recommend swing joints or other flexible piping joints as well as extra measures to secure the oil tank against falling-over.

The Unisource FireGuard flexible connector shown below is described by the manufacturer as extremely flexible and easy to install, and is used in both aboveground or underground installations where accommodation of movement or alignment problems are a concern.

Some industrial fuel piping installations will require swing joints or an equivalent flexible connector on fuel piping.

For industrial piping installations that might need swing joints see

• Charles A. Kircher Victor Vagliente Bahman Lashkari J. C. Jeing Steve Minor, Seismic Restraint Of Hazardous Piping Systems In Industrial Buildings (Phase I) [PDF] (1986) Jack R. Benjamin & Associates, Inc., Consulting Engineers, MOuntain Bay Plaza, Suite 501, 444 Castro St., MOuntain View CA 94041 USA - local copy saved as Seismic-Restraint-Hazardous-Piping-Kircher.pdf - retrieved 2025/01/10
• PEI, the Petroleum Equipment Industry, gives this explanation of Swing Joints used in the petroleum industry [Web article] - retrieved 2025/01/10
  Excerpts:
  
  Although swing joints are still used, in the U.S. they largely have been supplanted by flexible connectors.
  
  These “flex” connectors, 30 inches or so in length, are made of impervious plastic covered with a mesh of stainless steel or other material.
  
  They will bend freely in any direction, and are generally considered much more flexible and less likely to leak than swing joints.
• Unisource, FireGuard” Petroleum Flex Connectors for Above & Below Ground Use [Website] [Illustrated above] Unisource Manufacturing, 8040 NE 33rd Dr Portland, OR 97211 HUSA, Tel: 800-234-2566 - retrieved 2025/01/10