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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: mh0pe on November 18, 2020, 08:08:44 PM
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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#.
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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
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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.
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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
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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...
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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
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...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.
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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.
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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.
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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?
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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.
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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
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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.
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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
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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.
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Agree on cut hose causing the most havoc and it is pretty realistic to think upon impact the 5 gallon tanks secured with the flimsy hold downs letting loose, tank goes flying intact but the hose gets severed. In that case though, the tank probably is in the ditch somewhere so maybe the actual fire hazard from the cut hose really would not create increased fire in the bus.
Lately, this forum is starting to scare me. It's all FAKE busnut hysteria! Now back to regular bus news. LOL
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I'm part way through a bus conversion and would like some advice on the placement of a propane tank on my '91 102C3.
If you are worried about propane, then why use it?
Perhaps this photo is an excellent reason why the major conversion companies (Liberty, Marathon, Royale, etc.) tend to produce all-electric coaches?
Yes, it was a propane fire.
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Propane is only dangerous as a owner chooses to be damn look at the CNG buses, 18 wheelers,pickups and cars on the road today powered by CNG
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Perhaps this photo is an excellent reason why the major conversion companies (Liberty, Marathon, Royale, etc.) produce all-electric coaches?
Yes, it was a propane fire.
Just saying it was a propane fire doesn't tell us anything - what actually caused the fire? Was it a propane fire due to a faulty refrigerator? Did the regulator fail? Was the tank struck and damaged? Was this at all related to tank placement or failure?
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I wholeheartedly agree Richard. Despite safeguards that can be used, proper routing, protection, and good installation practices are paramount. Some tanks may have an outlet valve that shuts off in the event of a catastrophic leak but one of the best practices is to size the lines no larger than they have to be to feed the device using the propane. And of course never plumb to the liquid side. The corrugated stainless flex pipes are a good choice for any place where relative motion can occur, whether from vibration, normal use and maintenance or collision.
Jim
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If it was a propane fire the fridge wasn't the culprit the door is still intact, maybe a furnace fire those are usually caused by lint build up caused by the owner never cleaning it,and I don't about the big guys never using propane if the owner wants it,I know of a 2010 Liberty bought new with a propane cook top
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Well RJ at least the Solar panel in that picture you put up is in good condition..... ;)
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The location looks like where a battery fire would have stated
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One thing for sure is the propane tank did not blow up. LOL
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They rarely do. Really, that's a TV thing, that explosion business.
Jim
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Yeah, like tires screeching on sand and dirt, and locomotive blowing up in Unstoppable.
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Here's a class C motor home engulfed in flames. At about 2:20 you'll notice what appears to be a propane tank letting loose. Not really an explosion - more of a burst of propellant into the fire. My guess it wasn't the tank itself cutting loose, as much as a line or valve melting.
https://www.youtube.com/watch?v=3zSjZVlnKHg
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Sounded like a pressure relief valve. Could have been an air tank or even the fuel tank. Was there any indication that the fire was caused by propane? I don't think there was anything salvageable at that point in the video and if the occupants hadn't already gotten away safely they weren't going to.
Jim
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Sounded like a pressure relief valve. Could have been an air tank or even the fuel tank. Was there any indication that the fire was caused by propane? I don't think there was anything salvageable at that point in the video and if the occupants hadn't already gotten away safely they weren't going to.
Jim
No indication what started the fire. If you listen to the guy talking he makes the comment "there goes my propane tank" at one point. I doubt the fire was caused by the propane tank, but who knows.
I was really trying to show that even in a fire like this the propane tank doesn't explode, per se.
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I mounted ours in the middle bay. Put in 2 7 gal tanks, that way when one runs out just switch over to the other and go get the empty one filled. Don't have to move the bus.
ED
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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.
My opinion is to have the tank(s) off when on the move.
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My opinion is to have the tank(s) off when on the move.
Most tunnels have caution signs about having pilot lights out while traveling through the tunnels. The newer style LP valves & hoses which we just upgraded to prevent the flow of LP weather the breech is at the valve or at the end of a hose "before the regulator". That's where the high pressure is but there is no flow prevention after the regulator. FWIW
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I'm of the opinion that the water heater should have a pilot light, and is the only thing on the RV that needs it. The rest can run sparkers, but the hot water is best with the pilot. This is because that way you will always have pretty warm water at the hot water tap without very much expense at all. I'm not really willing to give up that convenience.
You may say, why not go electric? There are reasons. Cost of course but disregarding that, as it's true that campground hookups are unmetered, there is the whole issue of sizing your water heater to your shower time. Yes you can install a bigger unit, or two of them but why do that if you don't have to? A typical RV shower will work acceptably well with a 5 gallon heater, but if you want to extend your shower time you can do that by adding an electric element to the propane burner and firing up both before your shower. Now here is where the pilot control helps. Say you've been out all day with just the pilot lit. You want a shower so you flick on the switch for the electric element and turn the gas control from pilot to on. You already have pretty warm water so by the time you can finish a beer the main burner has shut off and your shower is ready. Shortly after starting your shower the main burner will come back on, Meanwhile the electric element is also heating water. So you now have maybe 50% more shower time than before, with the same 5 gallon water heater.
I like that. I especially like always having warm water for washing hands or doing dishes and only having to turn the hot water tap to get it. Or if you are boondocking you can use only the propane to cut back on water usage by taking shorter showers and there is no drain on the batteries.
Jim
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Two of our favorite & always dependable conversion appliances is our vintage water heater & furnace. Great for boon-docking, they are basic pilot light units, no electronics of any kind including the radiant heat furnace. Sure we have a second 19 gal. electric water heater & a primary Atwood Excalibur forced air ducted furnace too but when you get right down to basics & want to sit still & static those two vintage appliances will maintain our comfort zone just fine...
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Gotta agree on the low-tech vintage propane furnace. Ours is a 30,000 BTU forced air furnace, but there are no electronics and it has a standing pilot. Pretty much fool proof if the fan keeps working and the thermocouple doesn't burn out.
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I'll go your bid and drop it one degree of simplicity. I'm still using the Dup-Therm gravity flow heater I riffled from an 80" 5 th wheeler. It has a pilot light that must be lit before initial usage but then stays on. It produces 12,000 BTU and absolutely turns my little bus into an oven. The only modification I've made to it was to install a house style thermostat so I don't have to get on hands and knees to adjust it. That did require replacing the original gas regulator but it was an easy task. I've considered adding a couple of computer fans but just haven't gotten desperate enough for something to do to do it yet.
I should add that while under way I never leave my propane tank on and the tank is mounted securely to the frame rails mid way between the axles on the driver's side--though the passenger side is less likely to be "T-Boned". Jack