Maximum legal fuel capacities?

[Inner Love]

This thread is to quote & link to the maximum legal limits for vehicle fuel capacities - installed / in containers, gas limit / diesel limit / propane limit / total limit / max combined limit before needing to comply with a different set of regs to legally carry beyond that limit.

This thread is about maximum legal fuel capacities in the United States and Canada. I am probably the first bus nut who is going to max out legal fuel capacity in a RV-registered vehicle. If I am not the first I want to hear your war story.

I am going to have the aux system designed & installed professionally by a shop because I don’t want trouble. Hypothetically, if you do everything yourself with mismatched junkyard parts, connect everything with scrounged tubing and fittings, making it work with as little money as possible because “frugality is the midle finger to the CONsumer CULTure that is destroyin the planet!”. What retribution can you face by authorities for a virtuously janky auxiliary fuel system other than a Fix it ticket or impoundment?

I’ve heard of intercity buses lines in Mexico carrying hundreds of gallons of diesel in plastic drums placed in every bay, so they can drive nonstop through the dangerous regions with their main tank shot through. Because they’ve been robbed after losing their fuel because the bandits shot through their tanks to stop the bus. I’m mentioning this as an example of maxing fuel capacity - I don’t plan to explore Mexico in the skoolie until I can afford a total loss scenario.

I specifically want to know the interstate limits for carrying diesel in a RV-registered skoolie for the Lower 48.

I also want to hear your stories of crossing into Canada with a stash of fuel (several full gas cans / auxiliary tanks / 100 pounds of propane etc.). I know a lot of things are at the discretion of the border agent and I also know the duties on extra fuel will be more than any savings. Be polite to them they’ll be polite to you...

My question is “Could the aux tanks be designed in a way that the CBSA considers it part of the fuel system, and considers it not subject to duties? Or should I plan on drawing down as much as I can and pay the duties on the gallons they deem unreasonable?” A design like this will also help when I have to stop at those inland immigration checkpoints in the Southwest.

For me maxing out fuel capacity is not just about saving money, it’s saving time. Time is the most important asset you have, as time is non-renewable and finite - Money is renewable and infinite. Filling 500 gallons, It’s worth your time and money to drive the bus an hour across town or to the next town to save 20 cents a gallon.

For me the cost to max out fuel capacity will pay dividends. When I’m going to travel the Dalton, Dempster & James Bay Highway not just once in my life but multiple times. When I explore America and fill up once a season. When I visit California and have the option to not pay their fuel taxes on principle because I wont need to fill up. When Im watching the news anchor report on $5 gas, smiling because I have at least 300 gallons of diesel under the floor. When I’m able to ride out temporary fuel shortages, like another 1973 oil crisis replete with fuel rationing and even-odd license plate days; where in some places after waiting hours in line in a hot car to fill up you’re told you can only fill to 20 gallons and you can only fill one gas can.

[JoeNesquik]

Think about fuel going stale, so that’s a problem. Having so much extra weight would make miles per gallon turn into gallons per mile. You might end up losing money lugging around a literal ton of fuel. As for being shot at, bulletproof the fuel tanks. Saving time, good point. Just an idea. Take it for what it’s worth.

[magnakansas]

I can have two,stock fuel tanks, they sit between the frame rails and behind the rear axle. 40 gallons each tank. uses OEM switch valves and fuel level sending units and lower skid plates. No tanks out side the frame rails. dont know yet about propane tank... gonna go under there somewhere.


william

[Kubla]

My 1982 bluebird wanderlodge has a single 270 gallon fuel tank, I have driven semi tractors with 2 150 gallon tanks and seen larger. Make sure whatever tank you use is rated for fuel

[FamilyCircus]

Im planning on using one Freightliner classic or FLD120 tank which is 23" x 88" and holds 150 gallons. This will be in place of the stock cage tank which is only 60 gallons but takes tons of space and weighs a bunch. They are pretty cheap too, tons of them out there.

[Inner Love]

So, is there a legal limit to the maximum gallons you can have onboard an RV / vehicle registered as an RV?

[Mark_In_MA]

From what I can find doing some research (so far) :



You can carry a maximum of 1,000 gallons of diesel without a hazmat endorsement.
No single tank/container that's holding that 1,000 gallons can be over 119 gallons.

I don't know how the vehicles primary fuel tank figures into that equation - since you can buy tanks that will hold more then 119 gallons.

[Sehnsucht]

Originally Posted by Mark_In_MA

From what I can find doing some research (so far) :



You can carry a maximum of 1,000 gallons of diesel without a hazmat endorsement.
No single tank/container that's holding that 1,000 gallons can be over 119 gallons.

I don't know how the vehicles primary fuel tank figures into that equation - since you can buy tanks that will hold more then 119 gallons.

These are good general guidelines as they are the same guidelines used by the DOT for hazmat transportation. Regarding the exception for fuel tank capacities over 119 gallons, there are two guiding principles at play - one is that an affixed fuel tank is permanently secured to the vehicle versus being a portable cargo container which is secured but not permanent and fuel tanks are more rigid than cargo containers. Anything in bulk like a fuel tanker truck would end up requiring placards and that's not a box of trouble worth opening. Second is that >119 gal tanks have become less common based on a number of factors, including a more robust national fuel network infrastructure and increased fuel efficiency since the era of big rigs which toted 300-400 gallons for long hauls with few fuel stop options.

Pertaining to this topic with regards to skoolies, of course a fuel capacity upgrade is imperative if you're planning to do long trips but no reason to to overboard. A second fuel tank of equal capacity should be sufficient. Best location would be between the frame rails for impact protection. And at some point the added weight of too much fuel will become self-defeating as fuel economy declines in response. These are all good points previously raised and well worth considering from to learn from the past experience of others.

[Inner Love]

Now that I have my bus, I am planning ahead future steps. I have the original fuel tank, that is very space inefficient with the way it's secured to the frame. While I want to keep the front end looking original, I could fit up to 4 times the tankage in the space the original fuel tank and support structure is taking up.

No need to re-implement the wheel here. I am thinking of sourcing strapped-to-frame, boxy semi tractor tanks from a semi tractor junkyard. Are there are better fitting tanks for a skoolie? Perhaps 4-6 tanks, each equal size, with level balancing and distribution pumps. Then another 2 tanks of the same size to feed my diesel heaters using dyed diesel. Totaling out to 3-400 gallons. Get professional help with whatever not comfortable doing myself. If needed for insurance reasons, have tanks or lines professionally installed. Use hard lines if in the budget or required.

It's not just about traveling range. With this amount of diesel on board, I could park the bus in the Yukon and have heating fuel for months. I could have months of electricity with a diesel generator.

Good plan?

[mmoore6856]

Originally Posted by Mark_In_MA

From what I can find doing some research (so far) :



You can carry a maximum of 1,000 gallons of diesel without a hazmat endorsement.
No single tank/container that's holding that 1,000 gallons can be over 119 gallons.

I don't know how the vehicles primary fuel tank figures into that equation - since you can buy tanks that will hold more then 119 gallons.

haz mat is in pounds not gallons so your info would allow nearly 7,000 pounds of diesel which will get you in trouble fast

[mmoore6856]

damn internet

[CHEESE_WAGON]

Originally Posted by mmoore6856

haz mat is in pounds not gallons so your info would allow nearly 7,000 pounds of diesel which will get you in trouble fast

I've never heard of it being in lbs. I was trained in 2013 and haven't driven a rig on a regular basis since 2017 due to health issues, but what I was taught, is anything under 119 gallons is legal without HazMat. However, there is something in the code which states this does NOT apply to tanks supplying fuel to the chassis engine, which is why most Class 8 trucks offer tank options in the 120-300 gallon range. However, I can see why lbs might be a consideration as well, as 1,000 gallons of diesel = 7000 lbs, which is pretty much half of the GVWR of most smaller buses and trucks.

[Rwnielsen]

It's sold at the loading rack and transported by the pound because gallons fluctuate with temperature, same with oil.

[Sehnsucht]

Cheese Wagon mentions a good point of distinction which is the fuel carrying capacity of the vehicle's fuel supply versus supplemental fuel reserves in separate containers or fuel that is in transit essentially for commercial purposes. As I mentioned in an earlier post of this thread, semi trucks used to carry 300+ gallons back when they got 3-4mpg and out west you could go a long time between refuel opportunities. Today's semis are getting up to 10+mpg and there's a truck stop every 50-75 miles along the interstate highway system so many carry 150-200 gallons in two saddle tanks mounted to the frame.

If you plan to install or have installed permanent fuel tanks, I know of no official restriction on the capacity although I did find an unofficial answer from Google based on Cornell Law which purports a 500 gallon limit on the fuel system's rated capacity. Since that's not coming from the DOT, take it for what it's worth. Beyond the fuel system, if you get into auxiliary tanks which don't feed the engine or non-permanent (removable) containers for transporting extra fuel, you'll bump into the 119 gallon limitation at which point you're treading into the realm of hazardous materials transportation which is a commercial license requirement. You might get away with it because who's going to suspect a bus or RV has thousands of gallons of surplus fuel in all those belly boxes but if you're in a wreck and it doesn't go up in a fireball it's still going to dump a heckuva lot more fuel than they would expect in an RV collision which is going to raise flags. Also, paying for and then pumping that much fuel at once is going to hurt!

[mmoore6856]

Originally Posted by CHEESE_WAGON

I've never heard of it being in lbs. I was trained in 2013 and haven't driven a rig on a regular basis since 2017 due to health issues, but what I was taught, is anything under 119 gallons is legal without HazMat. However, there is something in the code which states this does NOT apply to tanks supplying fuel to the chassis engine, which is why most Class 8 trucks offer tank options in the 120-300 gallon range. However, I can see why lbs might be a consideration as well, as 1,000 gallons of diesel = 7000 lbs, which is pretty much half of the GVWR of most smaller buses and trucks.

its never been gallons as some haz is not liquid as in explosives. i been haz since 1980

[CHEESE_WAGON]

Originally Posted by mmoore6856

its never been gallons as some haz is not liquid as in explosives. i been haz since 1980

I think it depends on the material. HazMat can be solid, liquid or gaseous. Refer to Question 13 in the link below.


https://www.fmcsa.dot.gov/regulation.../section/383.5

[flattracker]

Both of my Crowns came with fuel tanks of about 95-100 gallons capacity. In the "old Crown" I added a 15 gallon tank for the generator, which runs on Gas, making the extra tank necessary.
On the "new Crown" I installed a 20 gallon tank for the generator (diesel) and will add a fuel transfer system later. My generator tank is between the frame rails. In Crowns made when mine were, the fuel tank is behind the rear axle and past the frame. I think I wouldn't mind adding another 20 gallon fuel tank in the trunk (diesel is not volital like gasoline), for emergency backup that would give me an addition range of 130 -150 miles if needed. By the way there are places in Oregon and Nevada where the distance to the next fuel stop is 90 - 135 miles (think hwy 95, 395).

[mmoore6856]

Originally Posted by CHEESE_WAGON

Attachment 54669

I think it depends on the material. HazMat can be solid, liquid or gaseous. Refer to Question 13 in the link below.


https://www.fmcsa.dot.gov/regulation.../section/383.5

It dont matter if its solid ,gas or liquid its pounds not volume that its measured by ask a fuel transporter. You need a endorsement to haul but every driver gets haz training at a basic level as they can haul 1000 lbs without a endorsement . Ihave the endorsement not just training and transported haz mat in both us and canada .now i reluctantly support driverless trucks

[CHEESE_WAGON]

Originally Posted by mmoore6856

It dont matter if its solid ,gas or liquid its pounds not volume that its measured by ask a fuel transporter. You need a endorsement to haul but every driver gets haz training at a basic level as they can haul 1000 lbs without a endorsement . Ihave the endorsement not just training and transported haz mat in both us and canada .now i reluctantly support driverless trucks

That's bulk fuel transport for resale, though, and under the 2011 code update, is not the same thing as increased capacity fuel supply tanks for the host vehicle's engine, which seems to be what the OP is asking about. You say you've had HazMat endorsement since 1980, but FMCSA code for HazMat and Tank endorsements changed in 2011, likely the reason you and I disagree here. And the link above clearly shows that FMCSA code was modified to stipulate a 119-gallon rule to tighten liquid HazMat and tank requirements while allowing high-capacity fuel tanks if supplying the engine.

That 119 gallon stipulation is also a requirement for tank endorsement, hazmat or not, but does not apply to vehicle-mounted fuel tanks supplying the engine. It does, however, apply to, say, a 250-gallon liquid tote containing an oil-based paint in a dry-van trailer, a likely reason the code was updated. And it still includes the 8,500-gallon fuel tankers used to deliver diesel and gasoline, while expanding it to cover such workarounds as hauling liquid HazMat on dry vans or stepdecks. I refused to haul a liquid tote load once because of that.

I'm not trying to argue with you mmoore, but I know what I'm talking about. FMCSA HazMat and Tank endorsement code was updated in 2011, and I trained in 2013, thus HazMat was explained to me from the updated code as follows:

Over 1,000 lbs of any solid, or 119 gallons of a liquid or gas, unless such tank supplies the host vehicle's engine. Period. And that is per the 2011 code changes. 7,000 lbs is way more than 1,000 lbs or 119 gallons. So actually, the updated code is more stringent than the superseded code that you state.

I believe the 2011 FMCSA code update I posted is meant to simplify in clarifying that fuel tanks only require HazMat if not supplying the transporting vehicle's engine, and hold over 119 gallons. I'm sure you've seen the squared-off tanks with built in pumps that sit in pickup truck beds, I know I have. Maybe construction workers hauling diesel to equipment on jobsites in auxiliary tanks, were somehow causing problems, but I believe this code change was aimed at liquid totes being hauled with dry vans and flatbed / stepdecks.

As I stated, the 2011 code revision stipulates over 1,000 lbs of any solid, or 119 gallons of a liquid or gas, unless such tank supplies the host vehicle's engine. Period. And that is per the 2011 code changes. 7,000 lbs is way more than 1,000 lbs or 119 gallons.

Which pretty much includes the 7,000 lb stipulation you mentioned, but at the same time supersedes in also clarifying that an 8,500 gallon fuel tanker that weighs 60,000 lbs, but has no connection to the tractor's engine, and swapping a bus' fuel tank for a 300 gallon unit are apples and oranges, at least where the code is concerned. Read the updated FMCSA code, it's all in there. You need only go to question 13 on the linked page I posted.

OP, to clarify here, you may upgrade your existing fuel tanks by replacing them with larger units without obtaining HazMat, as long as they are approved for the purpose. And yes, that includes a 300-gallon unit from a road tractor or a 1,000-gallon unit from a locomotive, as long as it is properly mounted, and does not leak. But be aware that 1 gallon of diesel is 7 lbs, so 300 lbs = 2,100 lbs, and 1,000 gallons = 7,000 lbs, which can and will conflict with max load of axle or tires, and ultimately, your bus' GVWR after conversion.

And a larger tank adds weight as well. Weight should be your primary concern here, but if you are planning to simply carry extra fuel, not upgrade your existing tanks, anything over 119 gallons will require Tank and HazMat endorsements, as capacity exceeding 119 gallons with no hard connection to supply the engine meets both requirements. In either case, don't forget to install a rubber isolator strip between the tank(s) and mounting strap(s).

[Inner Love]

Originally Posted by Fastlane

I have the original fuel tank, that is very space inefficient with the way it's secured to the frame. While I want to keep the front end looking original, I could fit up to 4 times the tankage in the space the original fuel tank and support structure is taking up.

After looking at the tank, it's actually very well built and space efficient, and is going to be kept. Only thing I don't like about the original tank is the fill hole being recessed so far back, over half of the nozzle rests behind the door when filling (not a big deal, probably designed that way to deter fuel theft).

I read your post CHEESE_WAGON, and will take that info into consideration.

I haven't measured anything, but I could have space for 150-200 more gallons of tankage, including the dyed diesel tank(s) for the diesel heaters. I would rather have 2 or 3 larger baffled tanks instead of 4 or 5 smaller tanks. I'm not planning on adding tankage this year, otherwise I'd post dimensions of my underbelly space and talk to truck / bus shops who install plumbed to the engine auxiliary fuel tanks.

At 7 MPG, 200 gallons will allow me 1400 miles of travel, months of heat in a Yukon winter, or months of power with a small diesel generator.

6-7 MPG is what I probably got on the drive home, revving at 2500 RPM to keep 55. Once I tune up, moderately aeromod, and raise gear ratios I dream of 9 MPG - at 55 at sub-2k RPM (should be doable with my engine post-build). Until I succeed in the Millionaire Fastlane, Fastlane will stay in the slowlane.

At 9 MPG, 200 gallons will allow me 1800 miles of travel. This is just my plumbed-to-engine tankage!

The tankage can pay for itself in the first 20,000 miles:

-Roundtrip to Alaska from California, Fuel stops in Oregon, Alberta and Alaska.

-California to Texas Roundtrip, fuel stops in Arizona, Texas. Once out of California, load up on cheaper fuel in Arizona. Refuel in Texas, Top up before starting the journey back to California, every mile driving on sub-$3 fuel you pumped in Texas, smile as you pass up $4 diesel.

-James Dalton Highway / Dempster Highway. Top up in Fairbanks, Enjoy every mile to Deadhorse, Refuel in Fairbanks. Top up in Whitehorse, Enjoy every klick to Tuktoyaktuk, Refuel in Whitehorse.

-James Bay Road. Top up in North Bay, Explore every mile, including the public branch roads. Refuel in North Bay upon return.

All of the above while generating electricity whenever you want while your entire living space is kept at 70°F 24/7.

Someone mentioned weight. I expect my permanent build to be around 5 tons dry, with all provisions (wet weight) being an additional 2-3 tons. These are imperial tons. Adding 1000 pounds of diesel fuel to this number is incremental. If I average 7 MPG, at worst I'll get 6.9 MPG with full tanks, and 7.1 MPG with 1/8th of a tank, all else being equal. I'm coming out ahead just on the dollars spent on diesel alone. Peace of mind, time savings, convenience, gas station freedom, oil crisis insurance, and unconstrained capacity for diesel heaters and electric generation are gravy.

With this amount of capacity, you're not just able to fill up at the cheaper gas stations, you're able to fill up at cheaper gas stations in cheaper states!