Monday, May 18, 2015

To Tank or Not To Tank - Auxiliary Fuel Tanks

Auxiliary fuel tanks have been a staple for the industry for many years. In recent times, the DOT has taken a more stringent look into these tanks.

Having an auxiliary tank in the bed of the truck, to many drivers, is well worth the expense and extra weight, and pays for itself by reducing the number of fuel stops and allowing the driver to purchase fuel in regions where it is less expensive.

If a driver has decided to invest in a new tank, he or she should be certain that it conforms to all regulations, but specifically §393.67:

Tank must conform to all rules in §393.67, and must be marked "Meets all FMCSA requirements for non-side-mounted fuel tanks"


The tests for these tanks are very specific and rigorous, and include leak tests and drop tests. These tests are designed to ensure that fuel does not leave the tank in a catastrophic way during a wreck of some kind, and every tank used legally in interstate commerce has passed these tests and bears the certification above.

Tank must be mounted in a "workmanlike manner."

This verbiage is a little grey, in that "workmanlike manner" is open to interpretation. The intent of the regulation is that the fuel tank not be able to shift, overturn, fall out, or otherwise move around while the truck is in motion or during a catastrophic event. Almost all legally approved tanks will have mounting points to allow them to be attached to the truck, and we recommend attaching them to the frame of the truck if at all possible, rather than just the bed. Consult the Driver's Handbook on Cargo Securement published by the FMCSA for guidance.

Must be marked appropriately

Auxiliary tanks that are compliant will bear certain identifying marks, such as:
  1. Month and year of manufacture
  2. Manufacturer's name
  3. Some way to identify the location of manufacture
You will find that most legal tanks will also have a liquid capacity rating in gallons marked as well
Any legally compliant tank will have the appropriate markings on an easily accessible and readable plate.

Tank of appropriate size

If you are a diesel driver, the maximum auxiliary fuel tank you can have is 450 liters (119 gallons). Anything greater than this and it could be considered transporting goods, in this case, diesel fuel, which places you in the the Hazardous Materials area of the regulation book.

Tank should be properly plumbed

The regulations regarding fuel lines, including protection of and tolerances for, is pretty specific. Having unprotected or damaged rubber hoses containing a combustible liquid is a bad idea, and the regulations reflect this. 
An adapter kit can be of help to plumb your auxiliary tank into your fuel fill hose.


Note that this list is not complete...we have just hit the high points. Also, bear in mind that these rules are for diesel, not gasoline. Using an auxiliary tank with a gasoline system is very different and, due to tank size restrictions, not worth the effort. We hope this information helps you in your decision to purchase, install, and use a compliant auxiliary fuel system.

Sources: FMCSR Parts 393.65 and 392.51, Driver Handbook on Cargo Securement Ch. 1

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1 comment:

  1. This is a very nice and informative blog the points you explained are clear and practical.

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