Where to mount propane tank?

[mh0pe]

I'm part way through a bus conversion and would like some advice on the placement of a propane tank on my '91 102C3. My primary concern is the canister exploding and putting someone at risk. I have GasStops to manage internal leaks, but for the canister itself, where would you place it? I'm based in California so placement low to the ground is out of the question.

Some thoughts:
- If I mount right below the headlights, I have sun overhead. I could fabricate a hood to go over it but I'm concerned about that heat. The walls are also pretty thin in that area.
- If I mount at the bottom, where one would install a towbar, I'm concerned about rear-end collision risk or impact with the ground around curbs or tight angles. Right now I don't have anything that overhangs there.
- If I mount in front of the rear axles, I should have some good clearance and height I think, this seems the most promising.
- I could use a cargo bay, but then I would imagine it's no safer for occupants than a rear mount as it's below the floor.

We're talking about 100#.

[TomC]

The only two things that are propane powered is the 3 burner stove with oven and the 40,000btu furnace-o which both are right next to each other with the propane tank (100# chassis mount) directly underneath. The big trick is to have gas sensors that are connected to the electric solenoid valve-that also has a manual switch inside so you can turn off the gas when not in use. I've had that system since installed in 1994, and just had my tank refilled. I've replaced the furnace (Atwood) once in the 26 years. I like it so much I repeated it in my truck conversion, except used a Suburban furnace since the exhaust is much smaller. Good luck, TomC

[richard5933]

Not sure why this is problematic?

Are you worried about explosion due to a collision or due to some type of internal failure with the cylinder? Avoid the front and rear and nearly all your collision risks are removed. Side impact can be protected against by not having the tank against the outer wall of the bus.

A couple of things that I can see as important in placement:

• It keeps the propane lines as short as possible to reduce opportunities for leaks.
• Location is isolated from other storage areas to reduce chance of accidental ignition of any leaks.
• Has adequate ventilation on the floor of the storage area to allow any leaks to vent to the outside. Propane is heavier than air and will go down and out.

My bus uses two 33-gal horizontal forklift tanks. They are mounted in a rack which is built inside an aluminum cabinet. The cabinet is located in the bay immediately forward of the rear axle. Lots of ventilation holes in the floor of the bay to permit any leaks to escape to the atmosphere. The aluminum cabinet is about 6" inside the bay, so even in the event of a side-impact collision it's protected.

Please say more about what your concerns are. Placement of a propane tank is generally not really difficult, although I have seen some less-than-ideal installations such as just strapping a few 20-lb cylinders in a bay.

[luvrbus]

There should be no concern with a ASME frame mount tank,those don't even have to be recertified every 5 years,they are made from 1/4 inch steel with 3/8 inch welded end caps,you can mount those anywhere and use a remote fill ,portable tanks are more convenient you can exchange the tanks but at a price,I pay $1.29 gal to fill my frame mount tank instead of $13.99 at Walmart up to $25.00 other places for 4 gals on the exchange program       

[lvmci]

I have a frame mount Manchester, 25 gallon, horizontally mounted tank. There is a bottom and top of the tank, it's not as obvious as it seems, make sure you identify it before mounting, best even with modern electronics, to not have it mounted in the same bay as any electronic device, that creates a spark of any degree, lvmci...

[Jim Blackwood]

I'm also going to get an ASME certified tank, because I don't want to deal with expirations. I was thinking about a single large tank but after installing my leveling jacks I may decide on two smaller ones instead, depending on what I can find. For me, the front bay with the generator (propane driven) is the clear choice. Adequate ventilation is of course a necessity. Conventionally, frame mounted tanks sit underneath so venting is never an issue like it can be in an enclosed bay. But ventilation is also needed for the genset. A propane detector in that bay would obviously be a good idea. This location is pretty well protected, being behind the front wheels. I'd just guess the driver is not likely to survive an impact that could rupture an ASME tank in that location. The mid or rear bay should be equally safe.

Jim

[richard5933]

...This location is pretty well protected, being behind the front wheels. I'd just guess the driver is not likely to survive an impact that could rupture an ASME tank in that location. The mid or rear bay should be equally safe.

Jim

Be careful with assumptions like that. When we had the head-on collision (Bus vs Honda) in our 4106 a few years ago, the impact shoved the front axle back quite a bit. It was shoved back enough for the wheel to put a decent dent in the bulkhead behind the axle. The impact was strong enough on the other side of the bulkhead to also put a pretty good dent in the side of the metal tool box which was riding in there. The bulkhead actually pushed back far enough to lock the tool box in the bay, necessitating tearing apart the tool box to get it out.

I'm not saying it's an unsafe area for the propane tank, just not to assume that it can't be touched in the event of a collision. We both walked away from the collision, but the bus did not.

[mh0pe]

Not sure why this is problematic?

My driving concern is that the leading cause of RV related deaths is going up in a ball of flames. Collision or otherwise, so I'm working on minimizing that as much as possible.

[mh0pe]

Be careful with assumptions like that. When we had the head-on collision (Bus vs Honda) in our 4106 a few years ago, the impact shoved the front axle back quite a bit. It was shoved back enough for the wheel to put a decent dent in the bulkhead behind the axle. The impact was strong enough on the other side of the bulkhead to also put a pretty good dent in the side of the metal tool box which was riding in there. The bulkhead actually pushed back far enough to lock the tool box in the bay, necessitating tearing apart the tool box to get it out.

NFPA 58 disallows placement interior to bulkheads/storage.

[richard5933]

NFPA 58 disallows placement interior to bulkheads/storage.

You're going to have to elaborate on what you mean here.

Are you saying that you are trying to mount the tank in a way that is totally open to the atmosphere and not inside a bay?

Nearly every commercial class A motor home I've seen has the tank mounted behind a bay door, although usually there is no floor in that bay to prevent trapping gas inside the bay. Lots of travel trailers and class C rigs where the propane tanks are stored in a bay, again with the required venting to the bottom.

Not enough clearance under a coach to mount a tank under the bays. Wouldn't want it on the front or rear either due to obvious collision concerns. On a bus the tank is going to have to be somewhere between bulkheads unless it's forward of the front axle or rear of the rear axle. Neither seems like a safe place for it.

I agree with your concern about fire, but most of those are going to be due to propane refrigerators. Regardless of where you mount the tank, you'll have to take proper precautions with the plumbing to provide a leak-free install, and you'll have to provide proper venting.

Without access to the NFPA code you referenced, I can't see the current edition. Are you sure that what you're looking at actually applies to RVs?

[windtrader]

By design a bus is many times structurally stronger than 99% of a run of the mill RV. That alone means no matter where you locate it inboard, it is protected far more. I'd not worry about it at all. Maybe an OG can recollect a bus conversion that caught on fire due to ruptured propane tank. It has to be very rare. Chances of blowing a steer and ending up off the road is a real concern.

[buswarrior]

If you are worried about propane, then why use it? There are alternatives.

Propane fires and lack of maintenance go hand in hand. No regular attention to lines and fittings, no cleaning of the burners, no adjustments or checking of anything.

Take care of your stuff, no need to worry.

Go all electric and worry even less?

Happy coaching!
Buswarrior

[windtrader]

Go all electric and worry even less?

BW - I am so close. If I run to Wally world and pick up a countertop induction plate and metal pan and pot, I'd be off the propane. Only thing running is the refrigerator which I simply flip to AC and off propane and the cooker and it's done.

In fact, one project is replace the 3-way Norcold with a 10cf residential to save a powerhouse full of wasted energy. Cooking with induction will draw some but easily accommodated with upgraded power system installed this summer.
Mini-split needs to use that space right behind driver now holding the propane tanks. So a practical reason to ditch the propane.

[Jim Blackwood]

A dent and a rupture are two very different things. Didn't someone post that the ASME tanks have a quarter inch wall? (and 3/8" end bells) Just shoving the wheel back into that is only going to shove it back too. You need something sharp and pointed to penetrate and rupture something that thick and that means hitting something big like a semi or bridge abutment. I don't think a fire would worry you too much after that.

But if it does, and you've ripped out the OTR HVAC, just put the tank in that location across from the fuel tank, in the middle of the bus. About as safe as you can get. Personally I think it's nonsense. Just stay away from the small flimsy portable tanks.

Jim

[richard5933]

You're probably correct about the tank itself not getting damaged easily. The plumbing going to the tank - that's a different story.

Wouldn't take much to sheer off a propane line or to pull one enough to cause a leak. Proper precautions do need to be made to have things securely mounted and properly shielded. Not that difficult, but it's amazing the amount of installations we see in buses where the propane tanks are pretty much an afterthought.