Compressed air tank location - good or bad idea?

cahill

cahill

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Looking to add a 2.5g air tank to my Wit's End York OBA system. It is rated to 200 psi and would probably be kept at 135 psi or so. Had planned to mount it under the driver side step but it looks more complicated to design a bracket and was hoping not to drill into any of the frame and just use existing mounts.

This led me to the front between the frame behind the bumper and just in front of the paperclip - where I guess a winch would be mounted. There are plenty of available tapped holes and the parallel frame will make fabricating a plate easier. I am limited to an angle grinder, drill and hack saw for tools :( but it should be doable. The only thing I am unsure of is whether or not a compressed tank in the front of the vehicle and just in front of the radiator is a good idea in the event of an accident. I have seen others mount it there but they had a bullbar for added protection. I am running a stock front bumper. I also have the tire under the vehicle so that space isn't an option.

So, long background for a simple question - good idea or bad idea to mount an air tank behind a stock front bumper?
 
george_tlc

george_tlc

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Had my tank mounted there for 20 or so years.

airtank.jpg


ARB and the tank is sitting under my m12000. So, lots of room :)

cheers,
george.
 
cahill

cahill

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Thanks for the reply, I guess I am just unsure how much of a hit a stock front bumper can take in shielding impact to the tank directly. Maybe what I am really trying to get at is how likely is a compressed air tank to explode from an impact? I have no background in that field, so it may be a needless concern but a pressurized metal tank taking a hit seems like at least some potential for an explosion. There is a safety valve on the tank set for 185 psi but don't know how quickly it will release pressure in the event of a sudden impact or if it will even mitigate that type or scenario. My guess is that it wouldn't and is designed to prevent over pressurization from a compressor.
 
cahill

cahill

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Airbags aren't supposed to have shrapnel in them from what I understand :), but yes, the engine and firewall etc will likely protect the passengers in the event the tank explodes.

What I don't want is to be in a small fender bender or hit a rock/tree and have the tank cause more damage than the vehicle otherwise would have sustained - ie shrapnel destroying the radiator and fan preventing me from getting home when otherwise I would have only had a bent front bumper that I could still drive home with. If it was a big enough impact to destroy the radiator anyway than it doesn't matter, but want to get a sense of the risk of an accidental explosion. Just like a small fender bender can set off the real airbags when a seat belt would do just fine, would hate for the tank to pop and damage the vehicle when the bumper would have been sufficient to protect it. Again, I am running a stock bumper but it might be just fine considering that the tank is centered between the frame rails and the bumper has those two frame rails 30 inches apart centered and directly attached to it giving it quite a bit of bit of support.
 
cahill

cahill

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Why would it be pressurized all the time?

That is a good point. I guess it wouldn't be most of the time but figure it would be when I am off road or if I forgot to discharge it. I don't plan on running any air horns etc to need it pressurized all the time.
 
LINUS

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Why would it be pressurized all the time?

+1

if you’re just on a milk run (or beer) - sure, it’s a nothing burger.

And even if you ran around aired up alot, I can think of alot of funky mods over the yrs that people have done / mostly wires - that is sketchy AF.

I’d do this, but I already just have a CO2 bottle / end result - it only goe in when I need it, but it sits in the cab / rear quarterpanel - If I got tagged something fierce, your tank > my tank location.

:meh:
 
flintknapper

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Thanks for the reply, I guess I am just unsure how much of a hit a stock front bumper can take in shielding impact to the tank directly. Maybe what I am really trying to get at is how likely is a compressed air tank to explode from an impact? I have no background in that field, so it may be a needless concern but a pressurized metal tank taking a hit seems like at least some potential for an explosion. There is a safety valve on the tank set for 185 psi but don't know how quickly it will release pressure in the event of a sudden impact or if it will even mitigate that type or scenario. My guess is that it wouldn't and is designed to prevent over pressurization from a compressor.
^^^^

There is ZERO chance this will happen. It's NOT a bomb. The tank will not rupture. A fitting will fail letting a small stream of air escape. Ever drained a compressor tank. That is what will happen, nothing more.
 
LINUS

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^^^^

There is ZERO chance this will happen. It's NOT a bomb. The tank will not rupture. A fitting will fail letting a small stream of air escape. Ever drained a compressor tank. That is what will happen, nothing more.

Good point.

Even if ruptured it neither will be like an explosion nor would a flying fitting go very far as encased as that location is.

You’d need to intentionally overpressure using an impressive PSI o get to shrapnel-level results.

That said - compressed air builds humidity that the condensate needs a drain, esp for say running air tools.

But nut welded around /in a low-point spot & either a teflon taped allen set-screw or buttonhead allen bolt would be a stout drain.
 
dsmud4u

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Thanks for the reply, I guess I am just unsure how much of a hit a stock front bumper can take in shielding impact to the tank directly. Maybe what I am really trying to get at is how likely is a compressed air tank to explode from an impact? I have no background in that field, so it may be a needless concern but a pressurized metal tank taking a hit seems like at least some potential for an explosion. There is a safety valve on the tank set for 185 psi but don't know how quickly it will release pressure in the event of a sudden impact or if it will even mitigate that type or scenario. My guess is that it wouldn't and is designed to prevent over pressurization from a compressor.
A stock bumper, not very much. You’ve got much bigger issues then worrying about the air tank if you’re rocking a stock bumper.
 
flintknapper

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Good point.

Even if ruptured it neither will be like an explosion nor would a flying fitting go very far as encased as that location is.

You’d need to intentionally overpressure using an impressive PSI o get to shrapnel-level results.

That said - compressed air builds humidity that the condensate needs a drain, esp for say running air tools.

But nut welded around /in a low-point spot & either a teflon taped allen set-screw or buttonhead allen bolt would be a stout drain.


I've run a York Compressor and 3 gallon tank on my Early Model Bronco for about 20 yrs now. I have a safety valve (pop off valve, 150 psi) on the tank and a 1/4" ball valve to drain the tank of condensate and oil. The air pressure regulator has never failed me...but IF it did, the pop off valve would release any excess pressure.

IF 'properly' set up....an air tank will never experience a situation (from a wreck) that would cause it to explode.

All air tanks must meet certain minimum standards for certification. Rupturing one in an accident is neigh on to impossible.

Corrosion is your greater concern.
 
cahill

cahill

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Thanks guys. I appreciate the feedback and glad to have a consensus from all that have replied. Thanks @scottryana for the perspective on pressures of different tanks. Thanks @nukegoat, @flintknapper, and @LINUS as well. I have very little experience with pressurized tanks so I figured it would be best to ask before doing. It will have a drain valve, blow off valve and a regulator so it shouldn't ever get over-pressurized. Off to the metal supplier to see what they have that I can work with.
 
LandLocked93

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A fitting will fail letting a small stream of air escape.
Just for reference, OP, this is not the same as a pop-off valve event.
My tank (for now) rests in the rear cargo area, exposed to the sun.
Nearly shat myself when it's pop-off activated once.
It's alot funnier now. :facepalm:
 
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cahill

cahill

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Well, ran to the metal supply the other day and got started. Here are my kindergarden level skills for fab work and would love to hear some feedback for ways to up my skills.

Started with a sheet of paper and taped it up under the frame and rubbed with with chalk - not a good choice as it didn't leave distinct marks and switched to a carpenters pencil to get a tracing of the frame and bolt locations. I figured they would be off slightly as the paper had a little bit of flex in it to be able to touch the frame in all areas (the frame isn't all on the same plane), but hoped it would be close enough.

Air Tank Mount 1


I then transfed the holes and shape to a cardboard piece the same dimensions as the metal plate I had purchased and used this as a test fit before cutting into the metal.

Air Tank Mount 2


Air Tank Mount 3


Seemed to line up well enough - the fron passenger bolt location was off center by about 1/16" so I chose not to transfer the 2 foremost holes to the metal piece and take them direcly from the bolt hole locations with a center punch.

Air Tank Mount 4


I then mounted it up and transfered the 2 front bolt locations as stated above and tightened down the bolts. This caused the metal to bend and deform a bit to the contours of the frame. I used 14ga steel for the plate as it was thin enough to allow for the metal to mold a bit where it needed to. I then placed the tank on it and positioned it where it would hopefully not interfere with anything and marked the mounting hole locations for the tank.

I then took of the plate, drilled the holes and painted it.
Air Tank Mount 5
 

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