Can the bus handle the weight?

[bertoliann]

Originally Posted by Hvbuzz

When I started my bus project, I had full intention of putting water on the roof. Some day I would still like to, but so far, I havn't really needed to yet as I can keep my 40 gallon filled pretty easily. I wasn't going to use a tank. Sewer pipe. Either 6" or possibly 8"pipe. Sewer is cheaper then water pipe but is still has the orings to keep it sealed. The biggest difference is price, the bigger fittings get expensive.

Here is a picture of a friend of mines RAGBRAI bus.
Untitled by Hvbuzz, on Flickr

They used 4" pvc and painted it black for solar heat and runs the lenght of the bus. You can't see it in that pic but there is another pipe on the other side then both pipes are Tee'd together. Has worked well for many years. They don't have a water heater either and I hear the showers are decent. The deck on top holds a ton of bikes every year too. I would not be worried about the weight if it is evenly spaced out like the pipe does. The pipe also keeps the "sloshing" to a minimum. I drive Line bucket trucks at work. Talk about top heavy trucks with the booms clear up over the cabs. My bus has never felt top heavy and I would feel comfortable with the weight of the water on top.

We have actually been talking about doing 8 inch pc running the length of the bus on both sides and possible the front and back. It would get us over 100 gallons at least which is far better than what we'd be able to fit under our bed and we'd still have our gravity fed water. I guess we're selling out 250 gallon water tank and investing in pvc.

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[Hvbuzz]

Originally Posted by bertoliann

We have actually been talking about doing 8 inch pc running the length of the bus on both sides and possible the front and back. It would get us over 100 gallons at least which is far better than what we'd be able to fit under our bed and we'd still have our gravity fed water. I guess we're selling out 250 gallon water tank and investing in pvc.

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I was thinking a U shape for mine. Where the pipe would come past the end of the bus and use a 90* elbows to tie the two pipes together across the back of the bus. Then on the bottom side back there, to tap off a line to go into the bus.

[rensch26]

I like the pipe idea much more. Weight is evenly distributed front to back. I'd still try to keep them over half full to prevent water from sloshing during braking and accelerating. I still don't know if I'd try 250 gallons. 2000 lbs is just a crazy amount of weight up there in my opinion.

[bertoliann]

We'd definitely have them all connected with the elbows so it was just one out. It does disperse the weight and then there isn't so much in one spot. And I agree that they'd either need to be mostly full or mostly empty while driving so it doesn't slosh a lot of water weight. It will also still give us quite a bit of water still. We want to be as off the grid as possible or at least have the ability to do so if we want. It will be a little more pricy for parts though.

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[turf]

buses are strong, it'll hold it.

a roof top tank would have lousy pressure if you are counting on gravity feed.
pressure is determined by elevation change. so the number of feet from the sink to the waterlevel in the tank multiplied by a constant of .433 psi/ft.

with say a maximum of 10' drop (13' tank and pissing on the ground) you might make 4 psi. inside the bus at waist level will only be 2 psi.

not worth it imo.

[ACamper]

Right now my bus ceiling is bare, you can see what it is made of. Basically it is just angle iron every 3-4 ft with sheet metal over it. Obviously not designed for weight..

2000lbs crashing tru the roof or tipping over on someone would be the equivalent of a car falling off the lift on someone.

[Hvbuzz]

Originally Posted by ACamper

Right now my bus ceiling is bare, you can see what it is made of. Basically it is just angle iron every 3-4 ft with sheet metal over it. Obviously not designed for weight..

2000lbs crashing tru the roof or tipping over on someone would be the equivalent of a car falling off the lift on someone.

Buses are also designed to withstand a roll over. Pretty sure a bus on its lid is more then water weight of a few hundred gallons.

[bertoliann]

Originally Posted by Hvbuzz

Buses are also designed to withstand a roll over. Pretty sure a bus on its lid is more then water weight of a few hundred gallons.

That's what we read. That buses were designed to retain their shape in the event of a roll over so it would seem that the roof could support quite a bit of weight

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[Rusty]

Originally Posted by bertoliann

That's what we read. That buses were designed to retain their shape in the event of a roll over so it would seem that the roof could support quite a bit of weight

Rollover is 1-time deal in emergency situation where the bus is garbage after the incident vs continual dynamic stresses on the welds.

It'd work, until it didn't. Those South American buses are reinforced. The ones I rode in Ecuador had inner steel square tube added.

[Greatestrr]

You could definitely shur up your framing to hold a massive roof load. Think roll cage

[ACamper]

Originally Posted by Hvbuzz

Buses are also designed to withstand a roll over. Pretty sure a bus on its lid is more then water weight of a few hundred gallons.

They are designed to retain some shape in a roll. But a roll is a different type of weight distribution then dead weight sitting on top of something. Also like Rusty was saying after a roll the support system will be broken. Once a support system is broken it is just a matter of where it is collapsing.

I am not a structural metal engineer but my backyard mechanic self thinks it would be a very bad idea to put that much weight on top of a school bus.

[Versatile]

A lot cool things can be added that you cannot use while in motion.

[Iceni John]

That is the daftest idea I've heard on this forum for a long time! I have 220 gallons of water under the floor (where it needs to be), plus another 180 gallons of gray and poo tanks, and ten batteries in total (2 start and 8 house), and propane, and a generator, and a big pass-through storage bay, and god knows what else, all under the floor, so why are you even thinking of doing this? What's your objection to using pumps?

However, if the bus is permanently going to be up on blocks and driven at all, do it.

John

[Rusty]

Transit buses put CNG tanks on the roof, but it may be designed for the load.

[cowlitzcoach]

If you were to mount a tank on the roof I think that would be a super bad idea! If you retained the original steel ceiling I wouldn't be too concerned about the squashing factor. I would be more super concerned about the sloshing factor. I have driven water trucks with 3,000+ gallons of water in them. Even with baffles going into turns, coming up to a stop, or taking off from a stop can give you a real thrill. It is especially exciting when the tank is half full!

Mounting sewer pipe, even a couple of them on both sides, would eliminate the worst of the sloshing. But the added weight that high will tend to make the bus a bit tippy, especially on narrow roads with lots of turns or if you ever get into some serious side winds. The side loading of a bus is already pretty substantial when the wind gets to blowing. Adding more top hamper is going to just make the situation worse.

Most of the transit buses with roof mounted CNG tanks are also low floor buses. In other words, the floor of the major portion of the bus is about 24" lower than a conventional floor level bus. Moving that much weight lower (floor, floor support, and passengers) is going to counter the added weight on the roof a lot. But it still is going to be top heavy when the tanks are full. And they won't slosh.

If you have a school bus you have at least 24" of space under the bus where you can mount stuff outside of the frame rails. That is a lot of space to mount your tanks where the addition of 250 gallons of water is not going to adversely effect the handling of the bus.

[bertoliann]

Originally Posted by Iceni John

That is the daftest idea I've heard on this forum for a long time! I have 220 gallons of water under the floor (where it needs to be), plus another 180 gallons of gray and poo tanks, and ten batteries in total (2 start and 8 house), and propane, and a generator, and a big pass-through storage bay, and god knows what else, all under the floor, so why are you even thinking of doing this? What's your objection to using pumps?

However, if the bus is permanently going to be up on blocks and driven at all, do it.

John

Thank you for being insulting and not helpful. We have no objection to putting a pump in. We are throwing around ideas and it's already been decided not to put 250 gallons on the roof. It was a simple question that was answered many times in helpful ways.

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[MarkyDee]

If I wanted to take advantage of the black pipe on the roof for solar heating, I'd be sure to drain the water back to a tank between the wheels before moving. Then use a pump to get the water back up there when I'm stopped....

[Cabinbus]

i have seen 10 inch pvc pipe running the length of the bus filled with water on the roof paint it black its solar hot water and all gravity fed

[bertoliann]

Originally Posted by Cabinbus

i have seen 10 inch pvc pipe running the length of the bus filled with water on the roof paint it black its solar hot water and all gravity fed

Where do you even get pvc pipe that big? We looked at Menards and the biggest they had was 6 inch

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[mmoore6856]

Originally Posted by Rusty

Transit buses put CNG tanks on the roof, but it may be designed for the load.

Attachment 16222

i dont think they go on some of the curvy roads we do at the speeds we do i would worry about the roll factor sometimes i use that 85 mph speed limit in my truck (or bus)